Patent Application
20170121808
The present invention refers to the technical field of spraying materials, particularly to a method for enhancing the anti-fatigue performance of coating.
Because sprayed coating per se has relatively high porosity, and has the defects such as impurities or fiber cracks, the sprayed coating is prone to form crack propagation during the service, resulting in reduced working life. The enhancement of the coating performance of an existing surface mainly relies on the secondary process technology such as laser remelting and surface strengthening after the coating has been formed. Although these technological means have certain effects on the enhancement of the coating performance, these technologies can not significantly enhance the service performance of a coating which has been formed with fixed internal structures in nature since the macroscopical performances are the external characterizations of internal structures and qualities of the materials.
Sprayed coating is prone to be subjected to failure behaviors at the coating's interfaces during its service due to the weak binding strength thereof. Therefore, a lot of means have been applied to pre-spraying treatment, such as shot blasting, chemical degreasing, and the like.
However, degreasing by a chemical method can induce chemical reactions at surfaces, introduce new oxides, and result in changes of chemical components of a matrix surface; moreover, the employed chemical reagents are harmful to both human bodies and environment. Furthermore, after the completion of spraying, the matrix surface will deform to some extent, and the resulting cavities are arranged irregularly, the sizes and arrangements of the cavities can not be controlled effectively. Therefore, it is necessary to explore a new method as a pre-spraying treatment process to enhance the bonding force between the coating and the matrix.
Supersonic plasma spraying technology is widely applied in practical engineering field, because it can be used to prepare a relatively thick coating on large-scale parts. Plasma spraying technology can achieve coating of different systems by different kinds of materials, such as metal, alloy, ceramics, metal ceramics and plastics, and the sprayed coating also reflects different functions, such as wear resistance, thermal barrier, electrical conductivity, radiation protection, and the like. However, because sprayed coating per se has relatively high porosity, and has the defects such as impurities or fiber cracks, the sprayed coating is prone to form crack propagation during the service, resulting in reduced working life.
Texturing has been widely used in the research of antiwear and friction reduction. Through the method of texturing, the material performances have been greatly improved. The main reason why texturing can improve the tribological properties of materials is that it can store debris and lubricating oil, thereby provide continuous lubrication on the friction surface. Up to date, there are few researches on performing texturing of sprayed coating and thereby enhancing the anti-fatigue performance of the sprayed coating by various textured morphologies to change contact conditions. In addition, there are also few researches on using texturing as a pre-spraying treatment means to enhance the binding force of the sprayed coating or as a post-processing means to enhance the anti-fatigue performance of the sprayed coating, and matching the textured patterns with light and dark phase structures of sprayed coating to achieve the three-in-one textured locking effect and to finally achieve the enhancement in the service performance of the coating. Surface texture is a kind of bionic surface microstructure, which is a process technology that changes the geometry of the surface to further enhance the friction performance of a mechanical system. Through a variety of advanced surface microprocessing technologies (such as reactive ion etching, surface shot blasting treatment, electron beam lithography, mechanical micro-engraving and laser surface processing), the surface texturing or structure patterning possesses micro geometrical configurations (dot matrix) with particular and regular arrangement and size structures in a manner of bionic structure processing with special functions, so as to reduce the effective contact area of two friction surfaces, which shows unique advantages in terms of tribological properties of materials especially due to the reduced friction. Therefore, it is widely used to change the surface roughness of the parts, and then enhance the wear resistance and anti-fatigue performance of the surface of parts.
To enhance the working life of a coating, expand the performances of the coating, an object of the present invention is to provide a method for enhancing the anti-fatigue performance of the coating.
Another object of the present invention is to provide a textured pattern which can effectively enhance the anti-fatigue performance of sprayed coating.
To achieve the above objects, the present invention provides the following various embodiments.
In a first embodiment according to the present invention, the present invention provides a method for enhancing the anti-fatigue performance of coating by controlling the internal structure of the coating, which method is carried out by controlling the parameters during the spraying process such that the sprayed coating possesses certain spacing structure of light and dark layers.
The light and dark layers are also referred to as white and black layers, which are coating structures with alternate white layers and black layers; wherein the light layer (i.e. white layer) is the part that looks brighter, and the dark layer (i.e. black layer) is the part that looks darker.
Specifically, the method according to the first embodiment is carried out by spraying a matrix using the supersonic plasma spraying process; and adjusting the spraying process parameters constantly during the spraying process such that the entire coating possesses a spacing structure of light and dark layers with certain thickness.
Preferably, the matrix in this method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, the coating selected for the spray coating is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
Preferably, the process parameters of spraying are: spraying power 45-85 kW; wherein, for the black layer, the spraying distance is 80-140 mm, and the spraying speed is 6-10 g/min; and for the white layer, the spraying distance is 120-160 mm, and the spraying speed is 9-12 g/min.
More preferably, for the black layer, the spraying distance is 140 mm, and the spraying speed of black layer is 10 g/min; and for the white layer, the spraying distance is 100 mm, and the spraying speed is 8 g/min.
Preferably, the thickness of white layer and black layer is 1-7 μm.
More preferably, the thickness of white layer is 4-6 μm, and the thickness of black layer is 2-7 μm. Most preferably, the white layer is 5 μm, and the black layer is 4 μm.
According to the first embodiment, the present invention provides a textured pattern that can effectively enhance the anti-fatigue performance of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape, and the like.
More preferably, the density of the textured pattern is greater than 0% and less than 50%; the density means the area ratio of the textured pattern with respect to the surface of matrix or coating.
The advantageous effect of the first embodiment is as follows: by controlling the spacing and thickness of light and dark layers of the coating, the performances of coating can be optimized, such that the service performance and anti-fatigue performance of the entire sprayed coating is enhanced.
In a second embodiment according to the present invention, the present invention provides a method for enhancing the anti-fatigue performance of coating, which method is carried out by preparing textured patterns with different geometrical morphologies on the surface of sprayed coating through biological bionics simulation. The present invention uses the method of texturing after spraying, with the hope of providing continuous lubrication by means of texturing, changing the slip ratio of rolling contact fatigue, thereby investigating the contact fatigue performance of coating, and with the hope of optimizing the textured pattern based on this, thereby prolonging the service performance of coating.
Specifically, the method according to the second embodiment includes the following steps:
(1) spraying a matrix using a supersonic plasma spraying process; and
(2) subjecting a coating surface to texturing treatment using a laser process.
Preferably, the matrix in step (1) of the method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, in step (1), the process parameters of spraying are: spraying voltage of 120 V, spraying current of 440 A, spraying power of 55 kW, and spraying distance of 100 mm. The coating selected for spraying is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
Preferably, the specific process parameters of the laser process in step (2) are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth of the selected texture through controlling the laser energy, a regular textured pattern with certain size and certain density can be obtained by laser texturing method.
In this embodiment, the laser used is pulse laser, the energy and the processing times used determine the depth of the textured pattern; by the drawing software that comes with the system, the desired textured pattern with certain size and certain shape according to certain spacing can be drawn in advance, then the specimen surface can be possessed to obtain the textured pattern with fine size structure.
According to the second embodiment, the present invention provides a textured pattern that can effectively enhance the anti-fatigue performance of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as one or more of round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape.
More preferably, the textured pattern has an arrow shape.
More preferably, the density of the textured pattern is greater than 0% and less than 50%; and the density means the area ratio of textured pattern with respect to the surface of matrix or coating.
The advantageous effect of the second embodiment is as follows: the coating surface is textured; due to the fact that the difference in morphologies of textured pattern can change the contact conditions, and thereby results in the change in the contacting force, it can effectively enhance the anti-fatigue performance of coating.
In a third embodiment according to the present invention, the present invention provides a method for enhancing the bonding strength of coating, which method is carried out by preparing a textured pattern on a matrix surface through biological bionics simulation; and then preparing a coating on the matrix surface with the textured pattern.
Specifically, the method according to the third embodiment includes the following steps:
(1) preparing a textured pattern on a matrix surface using a laser process; and
(2) subjecting the matrix obtained in step (1) to spraying using s supersonic plasma spraying process.
Preferably, the matrix in step (1) of above method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, in step (1), the specific process parameters of laser process are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. The process controls the depth of the selected texture by controlling the processing times. The processing times are 3-7 times. A regular textured pattern with certain size and certain density can be obtained by laser texturing method.
Preferably, in step (2), the process parameters of spraying are: spraying voltage of 120V, spraying current of 440 A, spraying power of 55 kW, and spraying distance of 100 mm. The coating selected for spraying is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
In this embodiment, the laser used is pulse laser, and the energy and the processing times used determine the depth of textured pattern; by the drawing software that comes with the system, the desired textured pattern with certain size and certain shape according to certain spacing can be drawn in advance, then the specimen surface can be possessed to obtain the textured pattern with fine size structure.
According to the third embodiment, the present invention provides a textured pattern that can effectively enhance the bonding strength of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape, and the like.
Preferably, the density of the textured pattern is greater than 0% and less than 50%; and more preferably 30%.
The advantageous effect of the third embodiment is as follows: texturing is used as a pre-spraying treatment means; by texturing, the bonding strength of sprayed coating is enhanced, thereby the service performance of coating is prolonged.
In a fourth embodiment according to the present invention, the present invention provides a method for enhancing the fatigue strength of coating by double-layer texture coupling effect, which method is carried out by preparing a textured pattern on matrix surface and coating surface by biological bionics simulation. Surface texture is a type of biomimetic surface microstructure, which is a process technology that alters surface geometric configuration, thereby enhancing the friction property of mechanical system. Before spraying, the matrix surface is subjected to texturing because the textured pattern increases the contacting area of the coating and provides more locking point for the coating, it improves the bonding strength of sprayed coating, and texturing of coating surface improves the friction property of the material because it can increase the storage degree.
Specifically, the method according to the Fourth includes the following steps:
(1) preparing a textured pattern on a matrix surface using a laser process;
(2) subjecting the matrix obtained in step (1) to spraying using a supersonic plasma spraying process; and
(3) subjecting a coating surface obtained in step (2) to texturing treatment using a laser process.
Preferably, the matrix in step (1) of above method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, in step (1), the specific process parameters of laser process are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. The process controls the depth of the selected texture by controlling the processing times. The processing times are 3-7 times. A regular textured pattern with certain size and certain density can be obtained by laser texturing method.
Preferably, in step (2), the process parameters of spraying are: spraying voltage of 120 V, spraying current of 440 A, spraying power of 55 kW, and spraying distance of 100 mm. The coating selected for spraying is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
Preferably, in step (3), the specific process parameters of laser process are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth of the selected texture through controlling the laser energy, a regular textured pattern with certain size and certain density can be obtained by laser texturing method.
In this embodiment, the laser used is pulse laser, and the energy and the processing times used determine the depth of textured pattern; by the drawing software that comes with the system, the desired textured pattern with certain size and certain shape according to certain spacing can be drawn in advance, then the specimen surface can be possessed to obtain the textured pattern with fine size structure.
According to the fourth embodiment, the present invention provides a textured pattern that can effectively enhance the anti-fatigue performance of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape, and the like.
Preferably, the density of the textured pattern is greater than 0% and less than 50%; and the density means the area ratio of textured pattern with respect to the surface of matrix or coating.
The advantageous effect of the fourth embodiment is as follows: texturing is used as combined means of pre-spraying treatment and post-treatment of spraying; the bonding strength of sprayed coating is enhanced by texturing, and the anti-contact fatigue performance of sprayed coating is improved by surface texturing, thereby the service performance of the coating is prolonged.
In a fifth embodiment according to the present invention, the present invention provides a method for enhancing contact fatigue performance by optimized combination of texturing and coating process, which method is carried out by controlling the parameters during the spraying process such that the sprayed coating possesses certain spacing structures of light and dark layers, and then preparing a textured pattern with different morphologies on a surface of sprayed coating by biological bionics simulation. The light and dark layers are also referred to as white and black layers, which are coating structures with alternate white layers and black layers; wherein the light layer (i.e. white layer) is the part that looks brighter, and the dark layer (i.e. black layer) is the part that looks darker.
Specifically, the method according to the fifth embodiment includes the following steps:
(1) spraying a matrix using a supersonic plasma spraying process and adjusting the spraying process parameters constantly during the spraying, such that the entire coating possesses spacing structures of light and dark layers with certain thickness; and
(2) subjecting the surface of the coating to texturing treatment using a laser process.
Preferably, the matrix in step (1) of the method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, The coating selected for spraying is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
Preferably, the process parameters of spraying are: spraying power of 45-85 kW; wherein, for the black layer, the spraying distance is 80-140 mm, and the spraying speed is 6-10 g/min; and for the white layer, the spraying distance is 120-160 mm, and the spraying speed is 9-12 g/min.
More preferably, for the black layer, the spraying distance is 140 mm, and the spraying speed is 10 g/min; and for the white layer, the spraying distance is 100 mm, and the spraying speed is 8 g/min.
Preferably, the thickness of white layer and black layer is 1-7 μm.
More preferably, the thickness of white layer is 4-6 μm, and the thickness of black layer is 2-7 μm.
Preferably, the specific process parameters of the laser process in step (2) are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth of the selected texture through controlling the laser energy, a regular textured pattern with certain size and certain density can be obtained by laser texturing method.
In the embodiment, the laser used is pulse laser, and the energy and the processing times used determine the depth of textured pattern; by the drawing software that comes with the system, the desired textured pattern with certain size and certain shape according to certain spacing can be drawn in advance, then the specimen surface can be possessed to obtain the textured pattern with fine size structure.
According to the fifth embodiment, the present invention provides a textured pattern that can effectively enhance the anti-fatigue performance of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape, and the like.
Preferably, the textured pattern has an arrow shape.
More preferably, the density of the textured pattern is greater than 0% and less than 50%; and the density means the area ratio of textured pattern with respect to the surface of matrix or coating.
The advantageous effect of the fifth embodiment is as follows: by controlling the spacing and thickness of light and dark layers of the coating, the performance of the coating can be optimized; meanwhile, by use of the method of matching the spacing of the internal light and dark layers of the coating and the texturing of coating surface, the service performance and anti-fatigue performance of the entire sprayed coating can be enhanced.
In a sixth embodiment according to the present invention, the present invention provides a method for enhancing the anti-fatigue performance of coating by the coupling effect of three layer patterning, which method is carried out by preparing a textured pattern on matrix surface and coating surface by biological bionics simulation; controlling the parameters during the spraying process such that the coating possesses light and dark phases with certain thickness therein; and enhancing the anti-fatigue performance of the coating by the mutual coupling effect of surface texturing of the matrix, thickness of the pattern of light and dark phases of the coating and surface texturing of the coating.
Specifically, the method according to the sixth embodiment includes the following steps:
(1) subjecting a matrix surface to texturing treatment using a laser process;
(2) spraying the matrix using a supersonic plasma spraying process; and
(3) adjusting the parameters during the spraying process such that the coating possesses a certain structure of light and dark phases; and
(4) subjecting the coating surface to texturing treatment using a laser process.
Preferably, the matrix in step (1) of above method is further subjected to cleaning and polishing treatment. The matrix is preferably stainless steel, and particularly FV520B.
Preferably, in step (1), the specific process parameters of laser process are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. The process controls the depth of the selected texture by controlling the processing times. The processing times are 3-7 times. A regular textured pattern with certain size and certain density can be obtained by laser texturing method.
Preferably, in step (2), the process parameters of spraying are: spraying voltage of 120 V, spraying current of 440 A, spraying power of 55 kW, and spraying distance of 100 mm. The coating selected for spraying is NiCrBSi ceramic coating, which is a sprayed coating with a thickness of 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder is 50-60 μm.
Preferably, in step (3), the process parameters of spraying are: spraying power of 45-85 kW; wherein, for the black layer, the spraying distance is 80-140 mm, and the spraying speed is 6-10 g/min; and for the white layer, the spraying distance is 120-160 mm, and the spraying speed is 9-12 g/min; the thickness of light and dark layers of the coating is white layer of 4-6 μm and black layer of 2-7 μm, respectively. More preferably, the white layer is 5 μm, and the black layer is 4 μm.
Preferably, in step (4), the specific process parameters of laser process are: laser power of 80-120 W, scanning speed of 600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth of the selected texture through controlling the laser energy, a regular textured pattern with certain size and certain density can be obtained by laser texturing method.
According to the sixth embodiment, the present invention provides a textured pattern that can effectively enhance the anti-fatigue performance of sprayed coating. The pattern includes any of geometric patterns or combination of several geometric patterns, such as round, triangle, hexagon, groove shape, grid shape, arrow shape or stripe shape, and the like.
More preferably, the density of the textured pattern is greater than 0% and less than 50%; and the density means the area ratio of textured pattern with respect to the surface of matrix or coating.
In this embodiment, the laser used is pulse laser, and the energy and the processing times used determine the depth of textured pattern; by the drawing software that comes with the system, the desired textured pattern with certain size and certain shape according to certain spacing can be drawn in advance, then the specimen surface can be possessed to obtain the textured pattern with fine size structure.
The advantageous effect of the sixth embodiment is as follows: texturing of coating surface can effectively enhance the anti-fatigue performance of coating, because difference in the morphologies of textured pattern can change the contact conditions, thereby resulting in changes of contacting force; texturing of coating interfaces can effectively enhance the bonding strength of the coating, because the introduction of texturing can provide more anchor points for the coating; and the three-dimensional integrated textured pattern formed by matchment of texturing and the structure of the light and dark phases of the coating itself can enhance the service performance of coating. Therefore, the coupling effect of the three layer patterns regarding surface texturing of matrix, surface texturing of coating and structures of internal light and dark phases of coating can significantly enhance the anti-fatigue performance of coating.
The advantageous effect of the present invention is further described by Examples hereinafter.
It should be appreciated that these Examples are only used for the purpose of illustration, and they are by no means used to limit the protection scope of the present invention.
The Example refers to the preparation of coating according to the above first embodiment of the present invention.
Step 1:
The matrix was subjected to cleaning and polishing treatment at first. The matrix is preferably stainless steel, and particularly FV520B.
Step 2:
A high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment; the process parameters of spraying were: spraying voltage 120 V, spraying current 440 A, spraying power 55 kW, and spraying distance 100 mm. A coating with certain thickness was eventually obtained. The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
The process parameters of spraying were as follows: the spraying power is 80 kW, the spraying distance of black layer was 140 mm, the spraying speed was 10 g/min; the spraying distance of white layer was 100 mm, the spraying speed was 8 g/min; the thickness of light and dark layers of the obtained coating was: white layer of 5 μm, and black layer of 4 μm.
The coating prepared in Example 1 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Variation of Coating Hardness with the Thickness of White Layer in Light and Dark Phases of Coating
Coatings in which the white layer in the coating had a thickness of 1-3 μm, 2-4 μm, 3-5 μm, 4-6 μm, and 5-7 μm respectively were subjected to fatigue test using fatigue testing machine, and the testing results were shown in
2. Variation of the Anti Fatigue Strength with the Hardness of Coating
Coatings with different hardness were subjected to fatigue test using a rolling contact fatigue testing machine. It was found that, the fatigue strength of coating was increased with the increase of the hardness of the coating, as shown in
The Example refers to the preparation of textured coating according to the above second embodiment of the present invention.
Step 1:
A matrix was subjected to cleaning and polishing treatment at first. The matrix is preferably stainless steel, and particularly FV520B.
Step 2:
The matrix was sprayed using the supersonic plasma spraying method.
In the step (2), a high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment, the process parameters of spraying were: spraying voltage 120 V, spraying current 440 A, spraying power 55 kW, and spraying distance 100 mm. A coating with certain thickness was eventually obtained.
The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
Step 3:
The coating surface was subjected to texturing treatment using a laser process.
The laser power was 80 W, the scanning speed was 600 mm/s, and the frequency was 20 HZ. By laser texturing method, a textured pattern could be obtained with a depth of 60 m and a density of 30%. The specific patterns were: round and stripe shapes, hexagon, triangle, arrow shape, and stripe shape, as shown in
Among these, the stripe shape had a width of 50 μm and a strip spacing of 70 μm, as shown in
the combination of round and stripe shapes, wherein the stripe shape had a width of 50 μm and a strip spacing was 70 μm; the round shape was evenly distributed in the stripe shape texture, with a diameter of 50 μm, as shown in
the arrow shape had a width of 60 μm, wherein the width was the vertical distance of two sides, and the spacing of each arrow was 70 μm, as shown in
the hexagon had a side length of 60 μm and a spacing of 70 μm, as shown in
the triangle had a side length of 95 μm, and the spacing between fixed points of bases of two triangles was 70 μm, which were not shown in the Figure.
Except for the absence of texturing, experimental comparison was carried out under the same condition parameters as in Example 3.
The coating prepared in Example 3 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Fatigue Strength of Coating when the Coating Surface has Different Shapes of Textures
To test the influence of textured pattern of coating on the bonding strength of coating, the textured coating was subjected to fatigue strength test, the equipment used was conventional fatigue testing machine. The testing results are shown in
2. Variation of Fatigue Strength with Angles of Arrow Shape Texture
To test the influence of angles of arrow shape texture on the fatigue strength of coating, the angles of arrow shape were changed: the angles of prepared arrow shape were 15 degree, 25 degree, 35 degree, and 45 degree. The prepared patterns with different angles of arrow shape were subjected to fatigue test, and the used testing machine was the conventional testing machine.
The testing results are shown in
The Example refers to the preparation of coating according to the above third embodiment of present invention.
Step 1:
A matrix was subjected to cleaning and polishing treatment at first. The matrix was preferably stainless steel, and particularly FV520B.
Step 2:
Textured pattern was prepared on matrix surface using a laser process.
Firstly, patterns of combined texture of round and triangle, combined texture of round and groove shape, grid texture, and hexagon texture were drawn with drawing software, then textured patterns were prepared on matrix surface using a laser processing, as shown in
Among these, hexagon texture had a side length of 150 μm and a spacing of 200 μm, as shown in
Combined texture of round and groove shape, wherein the width of groove was 150 μm and the spacing was 200 μm; within the spacing of groove, rounds with a diameter of 100 μm and a lengthwise spacing of 200 μm were arranged, is shown in
combined texture of round and triangle, wherein the round had a diameter of 150 μm and a center spacing of 200 μm, and triangles with a side length of 100 μm were prepared in the gaps between rounds, as shown in
grid texture was distributed with grooves in both transverse and longitudinal direction, wherein the width of grooves was 150 μm and the spacing was 200 μm, as shown in
the specific process parameters of laser processing process: the used laser power was 90 W, the scanning speed was 700 mm/s, and the frequency was 20 HZ. The depth of textured pattern was controlled by the processing times, and the processing times was 6. Textured pattern with a depth of 80 μm was obtained, and the density of the textured pattern was 30%.
Step 3:
Spraying was carried out using a supersonic plasma spraying process.
A high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment in step (3). Process parameters of spraying were: spraying voltage 120 V, spraying current 440 A, spraying power 55 kW, and spraying distance 100 mm. A coating with certain thickness was eventually obtained. The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
Except for the absence of texturing, experimental comparison was carried out under the same condition parameters as in Example 5.
The coating prepared by Example 5 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Bonding Strength Between Coating and Matrix in Case of Different Shapes of Texture on Matrix Surface
A tensile tester was used to test the bonding strength of coating, in which the model number of the used tensile tester was MTS809 type electronic universal material testing machine. The manufacturer was MTS Company (USA). The textured patterns with different shapes prepared by Example 5 were then subjected to spraying, then subjected to tensile test. The final bonding strength was obtained by dividing the force for the coating to break from the matrix with the area of coating, and the testing results are shown in
2. Variation of Bonding Strength with the Density of Textured Pattern
The density means the area ratio of textured pattern with respect to the surface of matrix or coating. To test the influence of the density of textured pattern on bonding strength, the density of grid shape textured pattern was selected. The prepared texturing degree was 15%, 20%, 25%, 30%, and 35%. The prepared grid shape patterns with different densities were subjected to fatigue test, and the used testing machine was conventional testing machine. The testing results are shown in
The Example refers to the preparation of the double-layer texture coupled coating according to the above fourth embodiment of the present invention.
Step 1:
A matrix was subjected to cleaning and polishing treatment at first. The matrix was preferably stainless steel, and particularly FV520B.
Step 2:
Textured pattern was prepared on matrix surface using a laser process.
Firstly, patterns of combined texture of round and triangle, combined texture of round and groove shape, grid texture, and hexagon texture were drawn with drawing software, then textured patterns were prepared on matrix surface using a laser processing.
Among these, for combined texture of round and triangle, the round had a diameter of 150 μm and a center spacing of 200 μm, triangles with a side length of 100 μm were prepared in the gaps between rounds;
combined texture of round and groove shape, wherein the width of groove was 150 μm and the spacing was 200 μm; within the spacing of groove, rounds with a diameter of 100 μm and a lengthwise spacing of 200 μm were arranged;
grid texture was distributed with grooves in both transverse and longitudinal direction, wherein the width of grooves was 150 μm and the spacing was 200 μm; and
hexagon texture had a side length of 150 μm and a spacing of 200 μm.
The specific process parameters of laser processing process were as follows: the used laser power was 90 W, the scanning speed was 700 mm/s, and the frequency was 20 HZ. The depth of textured pattern was controlled by the processing times, and the processing times was 6. Textured pattern with a depth of 80 μm was obtained; and the density of the textured pattern was 30%.
Step 3:
Spraying was carried out using a supersonic plasma spraying process.
A high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment in step (3). Process parameters of spraying were: spraying voltage 120 V, spraying current 440 A, spraying power 55 kW, and spraying distance 100 mm. A coating with certain thickness was eventually obtained. The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
Step 4:
Coating surface was subjected to texturing treatment using a laser process.
The laser power was 80 W, the scanning speed was 600 mm/s, and the frequency was 20 HZ. By laser texturing method, textured pattern with a depth of 60 μm and a density of 40% can be obtained. The specific patterns were: round and stripe shapes, hexagon, triangle, arrow shape, and stripe shape.
For the combination of round and stripe shapes, the stripe shape width was 50 μm, the stripe spacing was 70 μm, rounds having a diameter of 50 μm were evenly distributed in the stripe shape texture;
hexagon had a side length of 60 μm, and a spacing of 70 μm;
triangle had a side length of 95 μm, and the spacing of fixed points of bases of two triangle was 70 μm;
arrow shape had a width of 60 μm; the width is the vertical distance of two sides, and the spacing of each arrow was 70 μm;
stripe shape had a width of 50 μm, and a spacing of 70 μm.
Among these, the schematic drawing of double-layer texture coupled coating with the matrix surface being coating surface of grid shape and the coating surface being arrow shape is shown in
Using the same condition parameters as Example 7, sprayed coating was prepared on non-textured matrix to conduct experimental comparison.
The coating prepared by Example 7 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Bonding Strength Between Coating and Matrix in Case of Different Shapes of Texture on Matrix Surface
A tensile tester was used to test the bonding strength of coating, the model number of the used tensile tester was MTS809 type electronic universal material testing machine. The manufacturer was MTS company (USA). The textured patterns with different shapes prepared by Example 7 were then subjected to spraying, and then subjected to tensile test. The final bonding strength was obtained by dividing the force for the coating to break from the matrix with the area of coating. The results indicated that, compared with non-textured matrix surface, textured pattern significantly enhanced the bonding strength of coating, and the bonding strength of coating varied with the shape of textured pattern. Among the selected patterns, grid pattern had the best bonding strength.
2. Fatigue Strength of Coating when the Coating Surface has Different Shapes of Textures
To test the influence of textured patterns of coating on the bonding strength of coating, the textured coating was subjected to fatigue strength test, and the used equipment was conventional fatigue testing machine. The results indicated that, compared with non-textured coating surface, coating surface with textured pattern possessed better anti-fatigue strength, and the fatigue strength of coating varied with the shape of textured pattern. Among the selected patterns, arrow shape texture had the best fatigue strength.
3. Variation of the Fatigue Strength with Bonding Strength of Coating
To test the variation of fatigue strength with bonding strength of coating, variation of fatigue strength of coating with bonding strength (i.e., the bonding strength of coating obtained in point 1) were tested on the basis of the textured patterns on matrix surface in step 1. The used equipment was fatigue testing machine, whose model number and manufacturer are the same as in point 2.
The testing results are shown in
4. Variation of Fatigue Strength with the Angles of Arrow Shape Texture
To test the influence of angles of arrow shape texture in point 2 of Example 8 on the fatigue strength of coating, the angles of arrow shape were changed: the angles of prepared arrow shape were 15 degree, 25 degree, 35 degree, and 45 degree. The prepared arrow shape patterns with different angles were subjected to fatigue test, and the used testing machine was the same as that in point 2 of Example 8. The results indicated that, the fatigue strength of coating varied with texturing angles, and texturing angles had an optimal value: when arrow texture angles were at 35 degree, and the fatigue strength of coating was the highest.
The Example refers to the preparation of coupled coating according to the above fifth embodiment of the present invention.
Step 1:
A matrix was subjected to cleaning and polishing treatment at first. The matrix was preferably stainless steel, and particularly FV520B.
Step 2:
A high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment in the step (2). The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
The process parameters of spraying were: spraying power 80 kW; the spraying distance of black layer was 140 mm, the spraying speed was 10 g/min; and the spraying distance of white layer was 100 mm, the spraying speed was 8 g/min; the thickness of light and dark layers of the obtained coating was: white layer of 5 μm, and black layer of 4 μm.
Step 3:
Coating surface was subjected to texturing treatment using a laser process.
The laser power was 80 W, the scanning speed was 600 mm/s, and the frequency was 20 HZ. By laser texturing method, textured pattern with a depth of 60 μm and a density of 40% can be obtained. The specific patterns were: round and stripe shapes, hexagon, triangle, arrow shape, and stripe shape.
For the combination of round and stripe shapes, the width of stripe shape was 50 μm, the stripe spacing was 70 μm, and rounds having a diameter of 50 μm were evenly distributed in the stripe shape texture;
hexagon had a side length of 60 μm, and a spacing of 70 μm;
triangle had a side length of 95 μm, and the spacing of fixed points of bases of two triangle was 70 μm;
arrow shape had a width of 60 μm; the width is the vertical distance of two sides, and the spacing of each arrow was 70 μm;
stripe shape had a width of 50 μm, and a spacing of 70 μm.
Except for the absence of texturing, experimental comparison was carried out under the same condition parameters as in Example 9.
The coating prepared by Example 9 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Variation of Coating Hardness with the Thickness of White Layer in Light and Dark Phases of Coating
The coating wherein the white layer in the coating had a thickness of 1-3 μm, 2-4 μm, 3-5 μm, 4-6 μm, and 5-7 μm, respectively, was subjected to fatigue test using fatigue testing machine. It was found that, the fatigue strength of coating varied with the thickness of white layer in the coating; when the thickness of white layer in coating was 4-6 μm, the fatigue strength of coating was the maximum, 780 HV.
2. Variation of the Anti Fatigue Strength with Hardness of Coating
Coatings with different hardness were subjected to fatigue test using a rolling contact fatigue testing machine. It was found that, the fatigue strength of coating was increased with the increase of the hardness of coating. Therefore, the thickness of light and dark layers corresponding to the maximum hardness, i.e. white layer 4-6 μm, was selected to obtain better anti-fatigue performance.
3. Fatigue Strength of Coating when the Coating Surface has Different Shapes of Textures
To test the influence of textured pattern of coating on the bonding strength of coating, the textured coating was subjected to fatigue strength test, and the used equipment was conventional fatigue testing machine. The results indicated that, the bonding strength of non-textured coating surface was 500 MPa, and the fatigue strength of coating surface with different shapes of texture was between 500 MPa and 600 MPa. Compared with non-textured coating surface, coating surface with textured pattern possessed better anti-fatigue strength, and the fatigue strength of coating varied with the shape of textured pattern. Among the selected patterns, arrow shape texture had the best fatigue strength, 590 MPa.
4. Variation of Fatigue Strength with Angles of Arrow Shape Texture
To test the influence of angles of arrow shape texture in point 3 of Example 10 on the fatigue strength of coating, the angles of arrow shape were changed: the angles of prepared arrow shape were 15 degree, 25 degree, 35 degree, and 45 degree. The prepared arrow shape patterns with different angles were subjected to fatigue test, and the used testing machine was the same as that in point 2. The results indicated that, the fatigue strength of coating varied with texturing angles, and texturing angles had an optimal value: when arrow texture angles were at 35 degree, the fatigue strength of coating was the highest.
The Example refers to the preparation of three-layer texture coupled coating according to the above sixth embodiment of present invention.
Step 1:
A matrix was subjected to cleaning and polishing treatment at first. The matrix was preferably stainless steel, and particularly FV520B.
Step 2:
The matrix surface was subjected to texturing treatment using a laser process.
Firstly, patterns of combined texture of round and triangle, combined texture of round and groove shape, grid texture, and hexagon texture were drawn with drawing software, then textured patterns were prepared on matrix surface using a laser processing.
Among these, for combined texture of round and triangle: the round had a diameter of 150 μm and a center spacing of 200 μm, triangles with a side length of 100 μm were prepared in the gaps between rounds;
combined texture of round and groove shape, wherein the width of groove was 150 μm and a spacing was 200 μm; within the spacing of groove, rounds with a diameter of 100 μm and a lengthwise spacing of 200 μm were arranged;
grid texture was distributed with grooves in both transverse and longitudinal direction, wherein the width of grooves was 150 μm and the spacing was 200 μm; and
hexagon texture had a side length of 150 μm, a spacing of 200 μm.
The specific process parameters of laser processing process were as follows: the used laser power was 90 W, the scanning speed was 700 mm/s, and the frequency was 20 HZ. The depth of textured pattern was controlled by the processing times, and the processing times was 6. Textured pattern with a depth of 80 μm was obtained; and the density of the textured pattern was 30%.
Step 3:
Spraying was carried out using a supersonic plasma spraying process.
A high-efficiency GTV F6 plasma spraying equipment from General Research Institute of mining and metallurgy was selected as the spraying equipment in the step (3). Process parameters of spraying were: spraying voltage 120 V, spraying current 440 A, spraying power 55 kW, and spraying distance 100 mm. A coating with certain thickness was eventually obtained. The coating selected for spraying was NiCrBSi ceramic coating, which was a sprayed coating with a thickness of about 100 μm obtained by supersonic plasma spraying, wherein the particle size of the NiCrBSi powder was 56 μm.
Step 4:
The parameters during the spraying process were adjusted, such that the coating had a certain structure of light and dark phases.
The process parameters of spraying in step (4) were as follows: the spraying power was 80 kW, the spraying distance of black layer was 140 mm, the spraying speed was 10 g/min; and the spraying distance of white layer was 100 mm, the spraying speed was 8 g/min; the thickness of light and dark layers of the obtained coating was: white layer of 5 μm, and black layer of 4 μm.
Step 5:
Coating surface was subjected to texturing treatment using a laser process.
The laser power was 80 W, the scanning speed was 600 mm/s, and the frequency was 20 HZ. By laser texturing method, textured pattern with a depth of 60 μm and a density of 40% can be obtained. The specific patterns were: round and stripe shapes, hexagon, triangle, arrow shape, and stripe shape.
For the combination of round and stripe shapes, the width of stripe shape was 50 μm, the stripe spacing was 70 μm, rounds having a diameter of 50 μm were evenly distributed into the stripe shape texture;
hexagon had a side length of 60 μm, and a spacing of 70 μm;
triangle had a side length of 95 μm, and the spacing of fixed points of bases of two triangle was 70 μm;
arrow shape had a width of 60 μm; the width is the vertical distance of two sides, and the spacing of each arrow was 70 μm;
stripe shape had a width of 50 μm, and a spacing of 70 μm.
Among these, matrix surface was coating surface of grid shape. The schematic drawing of three-layer texture coupled coating with the coating surface of arrow shape is shown in
Under the circumstances of the same condition parameters as Example 11, sprayed coating was prepared on non-textured matrix to conduct experimental comparison.
The coating prepared by Example 11 was subjected to rolling contact fatigue test, and the slip ratios of contact fatigue were changed to investigate the anti-fatigue performance of coating under the conditions of different slip ratios.
To measure various performances of the coating, Nova NanoSEM450 type scanning electron microscope was used to observe the geometrical morphology of the texture after spraying.
To measure the influence of different textured patterns on the anti-fatigue performance of sprayed coating, a rolling contact fatigue testing machine was used to test the fatigue performance of sprayed coating.
1. Bonding Strength Between Coating and Matrix in Case of Different Shapes of Texture on Matrix Surface
A tensile tester was used to test the bonding strength of coating, and the model number of the used tensile tester was MTS809 type electronic universal material testing machine. The manufacturer was MTS company (USA). The textured patterns with different shapes prepared by Example 11 were then subjected to sprayed coating, then subjected to tensile test. The final bonding strength was obtained by dividing the force for the coating to break from the matrix with the area of coating. The results indicated that, the bonding strength of the non-textured matrix surface was 50 MPa, but when the matrix surface had different shapes of textures, the bonding strength between coating and matrix was between 60 MPa and 70 MPa. Compared with non-textured matrix surface, textured pattern significantly enhanced the bonding strength of coating, and the bonding strength of coating varied with the shape of textured pattern. Among the selected patterns, grid pattern had the best bonding strength, which was 68 MPa.
2. Variation of Bonding Strength with the Density of Textured Pattern
To test the influence of the density of textured pattern on bonding strength, the density of grid shape textured pattern was selected. The prepared texturing densities were 15%, 20%, 25%, 30%, and 35%. The prepared grid shape patterns with different densities were subjected to fatigue test, and the used testing machine was conventional testing machine. The results indicated that, the bonding strength of coating varied with texturing density, and bonding strength showed the trend of first increasing and then decreasing, and texturing density had an optimal value; when grid texture density was at 30%, the bonding strength of coating was the highest.
3. Fatigue Strength of Coating when the Coating Surface has Different Shapes of Textures
To test the influence of textured pattern of coating on the bonding strength of coating, the textured coating was subjected to fatigue strength test, and the used equipment was conventional fatigue testing machine. The results indicated that, the bonding strength of non-textured coating surface was 500 MPa, and the fatigue strength of coating surface with different shapes of texture was between 500 MPa and 600 MPa. Compared with non-textured coating surface, coating surface with textured pattern possessed better anti-fatigue strength, and the fatigue strength of coating varied with the shape of textured pattern. Among the selected patterns, arrow shape texture had the best fatigue strength, 590 MPa.
4. Variation of the Fatigue Strength of Coating with Bonding Strength
To test the variation of fatigue strength with bonding strength of coating, variation of fatigue strength of coating with bonding strength (i.e., the bonding strength of coating obtained in point 1) was preferably tested on the basis of the textured patterns on matrix surface in step 1. The used equipment was fatigue testing machine, whose model number and manufacturer was the same as in point 2. The results indicated that, the fatigue strength of coating was increased with the increase of bonding strength, i.e. the coupling effect of three layer textures can significantly enhance the fatigue strength of coating.
5. Variation of Fatigue Strength with the Angles of Arrow Shape Texture
To test the influence of angles of arrow shape texture in point 3 on the fatigue strength of coating, the angles of arrow shape were changed: the angles of prepared arrow shape were 15 degree, 25 degree, 35 degree, and 45 degree. The prepared arrow shape patterns with different angles were subjected to fatigue test, and the used testing machine was the same as that in point 2 of Example 12. The results indicated that, the fatigue strength of coating varied with texturing angles, and texturing angles had an optimal value: when arrow texture angle was at 35 degree, the fatigue strength of coating was the highest.
6. Variation of the Fatigue Strength of Coating with Light and Dark Phases of Coating
The coating wherein the white layer in the coating had a thickness of 1-3 μm, 2-4 μm, 3-5 μm, 4-6 μm, and 5-7 μm, respectively, was subjected to fatigue test using fatigue testing machine. The results indicated that, the fatigue strength of coating varied with the thickness of white layer in the coating; and when the thickness of white layer in coating was 4-6 μm, the fatigue strength of coating was the maximum, 780 HV.
7. Variation of Coating Hardness with the Thickness of White Layer in Light and Dark Phases of the Coating
The hardness of the coating was tested by microhardness tester, and variation of coating hardness with the thickness of the light and dark layers was explored. The results indicated that, when the thickness of white layer in coating was 4-6 μm, the hardness of coating was the maximum, 780 HV.
8. Variation of the Anti-Fatigue Strength of Coating with Hardness
Coatings with different hardness were subjected to fatigue test using a rolling contact fatigue testing machine, and the testing results were shown in
The above described are only the preferred embodiments of the present invention. It should be noted that, those skilled in the art can also make several changes and modifications without departing from the technical principles of the present invention, and these changes and modifications should also be regarded as within the protection scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201510740875.X | Nov 2015 | CN | national |
| 201510740882.X | Nov 2015 | CN | national |
| 201510740891.9 | Nov 2015 | CN | national |
| 201510740995.X | Nov 2015 | CN | national |
| 201510741002.0 | Nov 2015 | CN | national |
| 201510741011.X | Nov 2015 | CN | national |
