Physical vapor deposition coating Physical Vapor Deposition (PVD) belongs to the field of new materials and advanced manufacturing research. It is an effective method for surface treatment. Its performance characteristics include: (1) High hardness, wear resistance (HV2500-4000);(2) Ultra-thin (1.5-5 microns on one side);(3) High temperature resistance (200-1200℃);(4) Self-lubricating (friction coefficient 0.05-0.35);(5) No pollution, zero emission (compared with other coatings and plating layers). Since the use of PVD process can greatly improve the performance of tools, molds, mechanical parts and friction and wear parts, this technology has very broad market application value and prospects. This project relies on the Institute of Surface Engineering of Shanghai University of Applied Technology. The multi-layer nano-micron superhard coating technology developed has won the first prize for Excellent Exhibits at the Shanghai City Industry Expo, and the amount of funding received by various projects exceeds 7 million yuan.
Most domestic PVD coatings use a single layer coating (TiN) as the base layer and a binary or ternary alloy layer hard film as the surface layer, such as a single layer of TiN coating, CrN coating, and TiAlN coating. In the field of hard cutting, TiAlN coating is a single-layer coating that is commercialized and widely used. It mainly uses Ti+TiN as the base layer and then deposits a TiAlN layer. It can be used to cut hardened molds with a hardness below HRC45. However, the coating will often flake off during use. So on the overall technical level, although PVD coatings are in use, there are still many areas that need to be improved.
Through the continuous implementation of a series of research topics, this project has achieved technological breakthroughs in the following aspects:
(1) Developed multilayer nano-micron thin film technology. Multi-layer film technology is innovatively used in the coating preparation process to solve the shortcomings of high stress in the coating and poor adhesion between the coating and the substrate. TiAlN, TiAlSiN, CrN and diamond-like carbon (DLC) coatings with a total thickness of about 3.5 microns were prepared and widely used in different manufacturing industries, truly achieving the nanoscale thickness of each film (35-44 nm/layer).
(2) Developed low-temperature coating technology. Excessive coating temperature will cause serious damage to the coated substrate, which may cause the substrate to be annealed, deformed, and even scrapped. In this study, the problem of stress concentration in the coating was successfully solved by using multilayer film technology, and the adhesion of the coating was improved. For this reason, for multi-layer TiAlN, TiAlSiN and Ti-based CrN coatings, the coating temperature can be less than 400℃; for diamond-like coating and CrN coating, the coating temperature is less than 100℃.
(3) Developed superhard coating technology. A quaternary high-silicon TiAlSiN coating was prepared on the basis of multilayer TiAlN coatings by adding oxidation-resistant Si elements. The coating has a Vickers hardness of more than HV4000 and a high temperature resistance of more than 1200℃. It can dry cut stainless steel, titanium alloy, and other difficult to machine materials, and the cutting hardness of hardened steel exceeds HRC65.
The results have been used in Shanghai City high-tech enterprise Shanghai Nagoya Precision Tools Co., Ltd.(knives), listed company Shanghai Ziri Packaging Co., Ltd.(bottle making mold), Shanghai City high-tech enterprise Shanghai Gaoluo Conveying Equipment Co., Ltd.(mechanical parts), Yuyao City Chaojie Metal Products Co., Ltd.(molds), Shanghai Yingshu Power Station Parts Co., Ltd.(knives), Shanghai Zhongchao Tools Co., Ltd.(knives), Companies such as Shanghai Nengcheng Precision Machinery Co., Ltd.(mold) and Shanghai Xinhuyuan Coating Technology Co., Ltd.(coating process) have been widely used, with an added output value of more than 300 million yuan.