Orthogonal test was used to study the sliding bearing (also called bearing) content and process parameters on the composition of reducing friction layer in plating solution on the properties of the coating, the electroplating process has been further optimized, significantly improve thequality of coating, the host plant on the quality of new type bearing sliding shaft requirements.
1 is used in internal combustion engines (also known as sliding bearing bush) is a key part ofthe vulnerable
Mechanical processing is completed, the general matrix on the inner surface of the first plating 1~ 3 μ m thick nickel (Ni) gate barrier layer, followed by electroplating 15 ~ 30 μ m thick Pb Sn Cu(PbSnCu) three element alloy antifriction layer, finally in all surface plating 1 ~ 2 μ m thick tin (Sn)or tin (PbSn) alloy protection lay
Provided in the inner surface of the Bush antifriction layer is designed to improve the Bushantifriction, wear resistance, corrosion resistance, mosaic, compliance, running, scuffing resistance, fatigue strength, compressive strength, bearing capacity, so as to improve their work performance, prolong the service life, and ultimately ensure high performance run the host.
According to the general requirements choose coating types. Bearing small engine generally use PbSn6 ~ 20 two element alloy, also have the use of lead and copper (PbCu), Pb Ag (PbAg) two alloys. With the passage of time and development of science and technology, the bearing use large, medium-sized diesel engine, internal combustion engine, with large load capacity, long service life, and should with lubrication, corrosion resistance, wear resistance, good performance. Practice has proved, in the traditional tin lead (PbSn6 ~ 20) two element alloyminus third group abrasive coating by adding a small amount of Mn copper (Cu) can significantly improve the properties of the coating. When the tin (PbSn6 ~ 20) adding 2 ~ 3% copper alloy coatings were two yuan, on the one hand because of copper and tin has certain dear lad, to a certain extent, inhibited the tin to the lining (i.e., matrix diffusion), to ensure the tin content andmicrostructure in the coating stability; on the other hand, due to the addition of copper, the hardness of the coating from the original HV8 ~ 10 to ~ 15 HV13, greatly improve the wear resistance of the coating and anti fatigue strength, thereby significantly improving the load capacity of bearing, service life is greatly prolonged.
If the lining metal directly electroplating antifriction coating, the coating of tin is easy to spread thebearing lining, after working for a period of time, the tin content in the film decreased to less than 6% (mass). And both copper base alloy lining or aluminum alloy liner, which contain a certain amount of copper, diffusion into the lining of tin and copper brittleness of intermetallic compounds (Cu3Sn). So not only the mechanical properties of the coating decreases, and the destruction of the lining structure, to make the overall mechanical properties of the lower bearing.To solve the problem is the electroplating a layer of nickel or nickel alloy barrier layers between the lining material and antifriction layer (also called the gate layer and barrier layer), to suppress the tin to the lining diffusion.
Tin or tin alloy layer of protection in addition has a certain role in corrosion, bearing the period can also spread way to supplement the content of antifriction layer of tin, to make the contents of each component in a relatively stable state. In addition, because of the protective layer does not contain copper, relatively soft, so bearing in initial stage can reach a good run for work.
Electroplating process this paper examines Bush antifriction layer.
The development process of the 2
Reduction of friction coating started early in foreign countries. 1920 by Gro AF (J.Grooff) proposed the first patent electroplating tin lead alloy, used in electroplating and surface naval torpedo gas cylinders, electroplating to twentieth Century forty years for bearing bush. In 1952 Schultz(Schults) proposed in aluminium and aluminium silicon (AlSi) electroplated tin copper alloypatent three yuan. In 1953 Scherf (Schoefe) review published using tin copper alloy bush. In 1976, Jong-Sang Kim, Pyun and Hyo-Geun Lee Su- iota iota published "crystal orientation tincopper plating and microstructure of the thesis". In 1980 Beebe (Beebe) proposed copper containing 2 ~ 3% (mass), tin is 9 ~ 12% (mass), the remaining three element alloy electroplatingproduction process of copper, plating thickness of 15 μ M. In 1982 Wortmann (Waterman), three element alloy plating bath copper ion (Cu2+) replacement solutions to problems
The antifriction alloy coating research and application of late. At the beginning of 1960, WuhanResearch Institute of materials protection and hailing the first parts factory first developed and used for the production of brush plating Pb Sn alloy plating process has been used for boatengine. In twentieth Century seventy time metaphase, Shanghai alloy bush factory and ShanghaiHudong Shipyard on the bearing of Cu Sn alloy plating process are studied in detail.
In 1985, Harbin Institute of Technology electrochemical department and company Chinashipbuilding factory four six six joint research lead bronze bearing on electroplating tin copperalloy three yuan reduction process friction layer, and has been used in production. In 1989,Dusanka Radoric published "in fluoborate bath to hydroquinone (on a benzenediol) for lead tin alloy plating additive paper". At the end of twentieth Century, Nantong bearing factory, Fan Jiahua,Jiang Zhidong, Wuhan Research Institute of materials protection of Ceng Liangyu, Yang Xiangui,<
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