Patent Application
20100227141
The present disclosure relates generally to a protective coating for industrial parts.
Currently, the working surfaces of industrial dies are often coated to increase their useful life. Such coated industrial dies are used in production operations until the coating established thereon fails, such as by breaking, delaminating or totally wearing off the underlying die in certain areas. In such instances, the dies have to be taken out of production for resurfacing and recoating of the working surfaces. This may be undesirable, at least in part because it may cause disruption of the production schedule, cost increases due to the reworking of the die working surfaces, and general loss in production time.
A protective coating for industrial parts is disclosed herein. The protective coating includes a first protective portion and at least one additional protective portion positioned on the first protective portion. The first protective portion includes marker particles in a first coating matrix. The marker particles make up from 5 to 40 volume percent of the first protective portion, and each marker particle has an average diameter ranging from 0.01 microns to 100 microns. The at least one additional protective portion includes a second coating matrix, and, in the second coating matrix, either i) a decreased amount of marker particles in comparison to an amount of the marker particles in the first protective portion or ii) no marker particles.
Features and advantages of embodiments of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear.
The present disclosure relates generally to protective coatings for industrial parts, and various methods of making the same on such parts. In a non-limiting example, the industrial parts may be dies. Other non-limiting examples of such parts include general metal-forming tools, heaters, pre-heaters, presentation tables, and/or any metallic part in contact with forming sheet metal at any stage of the forming process. The protective coatings disclosed herein enable a user to determine, by simple visual examination of a color change on the coated surface of the industrial part surface, that the end of the useful life of the coated surface is approaching. This allows for the scheduling of recoating and/or resurfacing of industrial part surfaces before the current coating fails during operation. It is believed that such a warning system allows for better control of production scheduling and production times. By enabling the user to make the determination that the coating is near the end of its useful life, the use of the coated part can be stopped before damage to the part surface occurs. In some instances, this may reduce cost by eliminating the need for complete resurfacing of the tool.
The protective coating disclosed herein may be made via multiple methods. Embodiments of the protective coating and its subsequent wear after use are shown in
The phantom line in
In a non-limiting embodiment, the coating matrix used in the coating composition (or, when separate layers are included, in the composition of each layer) may be one or more of the following: fluorocarbon polymers, gold, gold alloys, aluminum, silicon, carbon fiber, carbon nanofiber, carbon filament, carbon nanotube, silicon dioxide, silicon-germanium, tungsten, silicon carbide, silicon nitride, silicon oxynitride, titanium nitride, zirconium oxide, aluminum bronze, calcium zirconate, pure aluminum, cobalt-molybdenum, chromium cobalt, aluminum oxide, tungsten carbide, copper-aluminum alloys, copper-nickel alloys, copper-tin alloys, copper-zinc alloys, chromium carbide, nickel graphite, 316 stainless steel, fused nickel chromium, high carbon-iron-molybdenum composite, fused nickel-cobalt, fused tungsten carbide, white aluminum oxide, zinc, copper, aluminum oxide-titanium nickel aluminide, molybdenum, fused nickel-cobalt, nickel chromium, chromium oxide, titanium dioxide, stainless steel, low carbon steel, oxide coatings on steel, phosphate conversion, tin alloys, vitreous enamels, nickel alloys, aluminum-titanium dioxide, and tungsten. It is to be understood that in embodiments including separate layers, the coating matrix of each layer may be formed of the same material or different materials.
In another non-limiting embodiment, the marker particles 120 can include either a) particulates which change color upon exposure to air, the particulates including metals selected from the group consisting of magnesium, copper, zinc, aluminum, silica and combinations thereof; b) encapsulated metal particles selected from the group consisting of carboxy-functionalized silver, carboxy-functionalized titanium dioxide, amine-functionalized gold, carboxy-functionalized cerium (IV) oxide, carboxy-functionalized Fe2O3, carboxy-functionalized CdS-capped CdTe, carboxy-functionalized palladium, carboxy-functionalized zinc oxide and combinations thereof, c) encapsulated solid dye particles selected from the group consisting of fluorescent colored particles, carboxyl colored particles, carboxyl fluorescent colored particles, carboxyl-polystyrene colored particles, dimethylamino fluorescent particles, fluorescent carboxyl colored particles, fluorescent carboxyl colored particles, fluorescent polymethylmethacrylate colored particles, colored polystyrene particles; and combinations thereof. The marker particles 120 can also include a combination of any of a), b) and c) above.
It is to be understood that the previously listed materials may also be used in each of the other example embodiments disclosed herein and discussed hereinbelow.
In another embodiment, similar to that shown in
The protective coating(s) 126, 226 disclosed herein used for surface modification and protection for an industrial part 112, 212 includes marking particles 120, 220 of nano or micro dimensions incorporated therein. Such particles 120, 220 enable the determination and warning of the end of the useful life of the treated working surface 114 (i.e., the coating 126, 226). The wear of the coating 126, 226 therefore warns of the need for resurfacing work before failure of the working surface 114. Such a warning system combined with an outer protective layer 118 (substantially without marking material 120, 220 therein) provides a way to assure proper servicing of industrial parts before catastrophic failures occur. It is believed that this system does not require specially trained personnel to make direct measurements on the working surface 114, 214 of the die 112, 212. Increased surface quality of the formed parts may be achieved, as well as a reduction in surface finishing costs.
In the embodiments disclosed herein, the marker particles 120, 220 constitute from 5 to 40 volume percent of the first protective portion/layer 116. Each marker particle 120, 220 has, in one embodiment, an average diameter ranging from 0.01 microns to 100 microns. It is to be understood that the additional protective portions/layers 118, 218, 224 formed on the first protective portion/layer 116 includes a decreased amount of the particles 120, 220 or none of the marker particles 120, 220 in a coating matrix.
An example of the method for forming an embodiment of the coating 126, 226 including separate layers is described herein. Different coating compositions are formed for each of the desirable layers. For each layer 116, 216, 224, 118, 218, the respective coating matrix is provided in a powder or liquid form. The desirable amount, if any, of the marker particles 120, 220 are added to the coating matrix. For example, the composition for the first layer 116, 216 will include the coating matrix and marker particles 120, 220 present in an amount ranging from 5 to 40 volume percent of the coating matrix. Similarly, the composition for the additional layer(s) 118, 224, 218 will include the coating matrix and less marker particles 120, 220 (than the layer 116, 216) or no marker particles 120, 220.
The next step is to apply the composition to form the first protective layer 116 to the industrial part working surface 114. The composition for the additional protective layer(s) 118, 224, 218 is then applied on the first protective layer 116, 216. As previously mentioned, the at least one additional protective layer 118, 224, 218 has either a lesser amount of the marker particles 120, 220 in comparison to the first protective layer 116, 216, or none of the marker particles 120, 220. The at least two protective layers 116, 216, 118, 218, 224 are applied to the industrial part working surface 114, 214 by one of several methods. These methods can be electroless metal plating, plating, physical vapor deposition, chemical vapor deposition, spraying, plasma spraying, burnishing, dripping, or combinations of any of the above.
In yet another embodiment, the method for forming the coating 126, 226 utilizes a single composition, as opposed to multiple separate layers. The method includes the following steps. Initially, a composition of the coating matrix (in a powder or liquid form) and marker particles 120 is generated. The next step is to apply the composition to the industrial part working surface 114, 214 to form the protective layer 126, 226. The marker particles 120, 220 in the protective layer 126, 226 sediment toward the region of the protective layer 126, 226 closest to the industrial part working surface 114, 214, thereby forming the first protective portion 116, 216 (i.e., the bottom half of the protective layer 126, 226). The settling of the particles 120, 220 causes a division within the protective layer 126, 226 to form the various portions 116, 216, 224, 118, 218. The protective layer 126, 226 is applied to the industrial part working surface 114, 214 by an applying method selected from the group consisting of electroless metal plating, plating, physical vapor deposition, chemical vapor deposition, spraying, plasma spraying, burnishing, dipping, and combinations thereof. In this example, the embodiment with the gradient may be formed by virtue of the fact that not all of the particles 120, 220 will settle into the same area of the coating.
In the embodiments disclosed herein, the total thickness of the protective coating 126, 226 on the industrial part work surface 114, 214 is from about 5 to 500 microns.
In one non-limiting example, the first protective layer 116, 216 includes from about 20 to 40 volume percent of the marker particles 120, 220, where the marker particles 120, 220 have an average diameter ranging from about 0.01 to 1 micron. In this non-limiting example, the total thickness of the coating 126, 226 ranges from about 5 to 50 microns.
In yet another non-limiting example, the first protective layer 116, 216 includes from about 5 to 20 volume percent of the marker particles 120, 220, where the marker particles 120, 220 have an average diameter ranging from about 1 to 100 microns. In this non-limiting example, the total thickness of the coating 126, 226 ranges from about 50 to 500 microns.
To further illustrate embodiment(s) of the instant disclosure, various examples are given herein. It is to be understood that these are provided for illustrative purposes and are not to be construed as limiting the scope of the disclosed embodiment(s). Where units are given as “parts” in the examples, they are all in weight parts, unless specified otherwise.
A protective layer was applied to the work surface of a die. The protective layer components applied by electroless plating included nickel, polytetrafluoroethylene (PTFE), and polystyrene fluorescent particles. The coated die was used to form aluminum parts. The color of the polystyrene fluorescent particles was not visible until the time when the outermost layer on the die work surface had begun to wear away. This occurred after a certain number of parts were formed. With continued use of the coated die work surface, an obviously different color appeared on the surface of the coating. In the experiment, the thickness of the initial coating on the die, the number of parts formed up to when the change in color was detected, and the coating thickness on the die at the moment when color was detected, were correlated to determine the number of possible parts to be formed by the coated die before the coating wore off completely. The useful life of the die coating was thus detected.
A protective layer was applied to the work surface of a die. The protective layer components applied by plasma spray included CrC/NiCr and silica particles. The resulting protective layer's silica particles were not visible until after the protective layer on the die work surface had begun to wear away. With continued use of the die work surface, an obviously different color appeared on the work away surface of the protective layer.
While several examples have been described in detail, it will be apparent to those skilled in the art that the disclosed examples may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
