All along, direct PVD coating on the surface of aluminum alloy has been a difficult industry problem.
In aluminum alloy materials, due to the strong activity of aluminum elements, it is difficult for aluminum alloy materials to pass corrosion resistance tests such as salt spray and artificial sweat after PVD vacuum coating.
If you have to do PVD coating on the aluminum alloy surface, you need to do about 30um thick water plating treatment on the aluminum alloy material surface, and then do PVD treatment on the water plating layer surface. However, this treatment method has the problems of complicated process, low yield, and water plating pollution.
If the aluminum alloy can be directly PVD coated, it has obvious advantages in yield, cost (especially in combination with die casting), environmental protection, and performance.
In view of this, the team of Professor Hu Zhudong of the School of Materials and Energy, Foshan University of Science and Technology has been committed to the research and development of direct aluminum alloy material PVD projects for more than four years. "After working hard in many aspects of materials, processes and equipment, we finally made a breakthrough, ending the history of aluminum alloy materials that could not be directly PVD coated for many years." Recently, Hu Zhudong said excitedly.
According to him, compared with the water electroplating (or anodizing) method, this technology has a strong metal texture and good customer experience; the product yield is high; the treatment method is environmentally friendly and non-polluting. With the more polluting water plating treatment, it is gradually banned The advantage of this treatment method is more obvious; this technology can also handle some products that cannot be processed by water electroplating. Such as die castings. The comprehensive treatment cost is currently equal to or slightly higher than that of water electroplating.
By comparing the aluminum alloy material PVD with the stainless steel material PVD, it can be found that after some brands of aluminum alloy PVD, the surface hardness can reach or be slightly higher than that of stainless steel PVD. Other properties and test levels are comparable to those of stainless steel PVD. And the replacement of stainless steel with aluminum alloys can reduce the overall processing cost by more than 30%.
Specific performance indicators of aluminum alloy materials after PVD treatment:
1. Can pass load-bearing vibration and wear resistance test for 2 hours (load-bearing varies from 80g to 160g according to requirements);
2. Can pass the neutral salt spray test for 48 hours, some can pass more than 100 hours (depending on the type of aluminum alloy);
3. Can pass drop test, artificial sweat test and other electronic product related package tests;
4. The hardness after PVD can be increased by more than 3.5 times; the hardness of some hard coatings can be increased to about 8 times of the hardness of the materials; the hardness of the coatings of some brands of aluminum alloys after PVD can reach or be slightly higher than that of stainless steel materials after PVD Hardness (here refers to Vickers hardness).
At present, the technical hand is mainly used in machine frame, camera bracket; smart wearable watch case, earphone parts; notebook case and other aluminum alloy products. "Samples have passed the package test of many first-line brands in the mobile phone industry. Among them, a camera bracket project for a certain mobile phone brand has been mass-produced on a small scale." Hu Zhudong introduced.
Smart Wearable Watch Case Headphone Parts
In the future, this technology may be applied to the surface coating treatment of metal parts such as automobiles and airplanes. "At the same time, with the tightening of environmental protection policies, this technology should gradually replace the currently polluting water electroplating, anodizing and other surface treatment methods should be a trend of choice."