Patent Application
20110305893
This application is one of the two related co-pending U.S. patent applications listed below. All listed applications have the same assignee. The disclosure of each of the listed applications is incorporated by reference into another listed application.
1. Technical Field
The present disclosure relates to aluminum alloy-and-resin composites, particularly to an aluminum alloy-and-resin composite having high bonding strength between aluminum alloy and resin and a method for making the composite.
2. Description of Related Art
Adhesives, for combining heterogeneous materials in the form of a metal (such as light metals) and a synthetic resin are demanded in a wide variety of technical fields and industries, such as the automotive and household appliance fields. However, adhesives are generally only effective in a narrow temperature range of about −50° C. to about 100° C., which means they are not suitable in applications where operating or environmental temperatures may fall outside the range.
Therefore, other bonding methods have been applied that do not involve the use of an adhesive. One example of such methods is by forming bonds through injection molding or other similar process. However, the bonding strength of the metal and resin can be further improved.
Therefore, there is room for improvement within the art.
Many aspects of the aluminum alloy-and-resin composite can be better understood with reference to the following figures. The components in the figures are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the aluminum alloy-and-resin composite. Moreover, in the drawings like reference numerals designate corresponding parts throughout the several views.
Referring to
The resin compositions 13 may be coupled to the surface of the substrate 11 having the nano-pores 111 by molding. During the molding process, molten resin coats the surface of the substrate 11 and fills the nano-pores 111, thus strongly bonding the resin compositions 13 to the substrate 11. Compared to the conventional injection molding process in which the aluminum alloy substrate is not electrochemically etched, the composite 100 in this exemplary embodiment has a much stronger bond between the resin compositions 13 and the substrate 11 (about quintuple the bonding force). The resin compositions 13 may be made up of crystalline thermoplastic synthetic resins having high fluidity. In this exemplary embodiment, polyphenylene sulfide (PPS) and polyamide (PA) can be selected as the molding materials for the resin compositions 13. These resin compositions 13 can bond firmly with the substrate 11.
It is to be understood that auxiliary components may be added to the resins to modify properties of the resin compositions 13, for example, fiberglass may be added to PPS. The fiberglass may have a mass percentage of about 30%.
A method for making the composite 100 may include the following steps:
The aluminum alloy substrate 11 is provided.
The substrate 11 is degreased. The degreasing process may include the step of dipping the substrate 11 in a sodium salt water solution for about 5-15 minutes. The sodium salt solution may include sodium carbonate having a concentration of about 30-50 grams per liter (g/L), sodium phosphate having a concentration of about 30-50 g/L, and sodium silicate having a concentration of about 3-5 g/L. The temperature of the sodium salt solution may be about 50-60° C. Once degreased, the substrate 11 is removed from the sodium salt solution and rinsed in water.
The surface of the substrate 11 is smoothened. The smoothening of the substrate 11 may include the step of alkaline eroding. The alkaline eroding process may include the step of dipping the substrate 11 in an alkaline water solution for about 3-5 minutes. The alkaline solution may include sodium hydroxide having a concentration of about 10-50 g/L. The alkaline eroding process smoothes the surface of the substrate 11 so that the smoothed surface of the substrate 11 will be more uniformly electrochemically etched to obtain a narrower range of diameters of the nano-pores 111 of the substrate 11. Next, the substrate 11 is removed from the alkaline solution and rinsed in water.
The substrate 11 is electrochemically etched to form the nano-pores 111. The electrochemical etching process may be carried out in an acid water solution containing sulfuric acid and phosphoric acid, with the substrate 11 being an anode, and a stainless steel board or a lead plate being a cathode. The sulfuric acid may have a concentration of about 30-50 ml/L, and the phosphoric acid may have a concentration of about 20-60 ml/L. The electric current density through the acid solution is about 2-4 ampere per square decimeter (A/dm2). Electrochemical etching the substrate 11 may last for about 8-15 minutes, which is considerably less time and more effective than an anodizing process (about 20-60 minutes) for forming nano-pores. Next, the substrate 11 is rinsed in water and then dried.
During the electrochemical etching process, Al on the surface of the substrate 11 loses electrons to form aluminum ions in the acid solution (Al-3e=Al3+), as such, the substrate 11 is etched and nano-pores 111 are formed.
In the exemplary embodiment, the electrochemical etching process is substantially different from the anodizing process for aluminum alloy, which is substantially the process of forming alumina having nano-pores on the aluminum alloy.
Furthermore, compared to conventional chemical etching process, the electrochemical etching process in the exemplary embodiment is effective in forming nano-pores in the substrate 11, and the nano-pores 111 are of a more uniform shape, with a narrow range of diameters, and are evenly distributed in the substrate 11.
Referring to
Tensile strength and shear strength of the composite 100 have been tested. The tests indicate that the tensile strength of the composite 100 is greater than 10 MPa, and the shear strength of the composite 100 is greater than 20 MPa. Furthermore, the composite 100 has been subjected to a temperature humidity bias test (72 hours, 85° C., relative humidity: 85%) and a thermal shock test (48 hours, −40˜85° C., 4 hours/cycle, 12 cycles total), such testing did not result in decreased tensile strength and shear strength of the composite 100.
It is believed that the exemplary embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its advantages, the examples hereinbefore described merely being preferred or exemplary embodiment of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010197108.6 | Jun 2010 | CN | national |
| 201110058897.X | Mar 2011 | CN | national |
