Because of the special properties of aluminum, the electroplating of die-cast aluminum parts requires special pre-treatments, and these pre-treatments need to be adjusted due to different aluminum materials and different parts. It cannot simply follow the general process. Therefore, for workers engaged in electroplating of die-cast aluminum parts, sometimes it is necessary to do a test of electroplating treatment of die-cast aluminum parts. To carry out this test, the first step is the selection of the pretreatment process and the design of an improved method.
Die-casting aluminum parts china's electroplating pre-treatment includes four important processes including degreasing, acid etching, chemical plating or replacement plating, and pre-plating. The key is electroless plating or displacement plating, so the tests often done are concentrated on this process. Of course, different aluminum materials and different processing methods have different requirements for pre-treatment.For example, the pre-treatment of die-cast aluminum parts and rolled aluminum parts are very different, and even the same processing method, different aluminum materials are different. The pretreatment process, such as the amount of copper in aluminum, directly affects the adhesion of its coating. The test of the pretreatment scheme for the electroplating of die-cast aluminum parts is also a systematic comparison test, which requires the sample to be treated with different selected pretreatment processes, and then subjected to the same electroplating process, and then the binding force is tested. The main point of the test is to ensure that all processes are the same except for the different process points, otherwise there is no comparability and no evaluation can be made.
Die-Casting Aluminum Parts China
There are four common methods for plating of die-casting aluminum parts:
1. Phosphating of aluminum
The effects of promoters, fluorides, Mn2 +, Ni2 +, Zn2 +, PO4; and Fe2 + on the phosphating process of aluminum were studied in detail by using SEM, XRD, potential-time curve, and film weight changes. Studies show that: guanidine nitrate It has the characteristics of good water solubility, low dosage and fast film formation.It is an effective promoter for aluminum phosphating: fluoride can promote film formation, increase film weight, and refine grains; Mn2 + and Ni2 + can significantly refine grains. Make the phosphating film uniform and dense and can improve the appearance of the phosphating film; when the Zn2 + concentration is low, the film cannot be formed or the film formation is poor. As the Zn2 + concentration increases, the film weight increases and the content of O4 has a greater effect on the weight of the phosphating film. The content of PO4. Increases the weight of the phosphating film.