Study On Process Of Al-Sn-Cu Bearing Coating Preparation By Magnetron Sputtering And Its Performance

Nowadays,many industries have been developed rapidly such as automobile,steamship and aerospace.It also promoted the development of the high-speed engine.The requirements for engine is get higher and higher.Bearing bush is an easy-loss part of operation mechanical which been used in large quantities.So they put forward higher requirements on bearing materials.Aluminum alloy bearing have been widely used in the bearing shell material,because its fatigue strength is high,its bearing capacity is strong,its compliance and its mosaicism is good.Also because of its pollution to the environment is small.At present about 70% of the bearing shell is aluminum alloy bearing in our country.But with the improvement of various performance indicators requirements to the bearings,aluminum alloy bearing bush also cannot meet the requirements of the modern industrial production to bearing materials gradually.Therefore,this paper will study the problems caused by low hardness leading to poor wear resistance and short service life of aluminum alloy bearing.The aluminum alloy bearing shell AlSn20 Cu bearing is been dealt with surface treatment method in this paper,in order to change the content of each component and the coating structure,to improve the surface hardness and wear resistance of aluminum alloy bearing shell,but do not affect the original compliance,embedded and anti-seizure premise of bearing surface.Research dc magnetron sputtering process parameters impact on the coating composition,structure and hardness.And on this basis optimize the parameters of magnetron sputtering.In the first part of this paper,by adopting control variable method carried out single factor experiment.By adjusting the parameter of magnetron sputtering in the process,such as sputtering power,sputtering time substrate temperature,vacuum degree,sputtering negative bias,sputtering pressure and other process parameters,to study influence on the organization structure,the sputtering rate and hardness of the coating,and the of the substrate binding force and so on of various parameters.Surface morphology with the substrate temperature change is obvious,and deposition rate with the sputtering power changes obviously.Through the test get the better parameters range for sputtering aluminum tin copper plating,and analyzed the experiment process and sputtering theoretical in magnetron sputtering process(substrate temperature of 60? to100?,sputtering time of 4h to 6h,sputtering pressure of 0.1Pa to 0.3Pa,sputtering power of 60 w to 80 w,target distance of 12 mm,the bottom vacuum more than 5×10-4).Secondly,in the best range of magnetron sputtering parameters design a group of orthogonal tests,and analyzed of the test results of the coating.Through comparing the primary and secondary factors and the optimal level of each evaluating index,analyzed and determined the optimum process parameters of magnetron sputtering.The best process parameters obtained by orthogonal experiment of dc magnetron sputtering is substrate temperature 80? + sputtering time 6h + sputtering pressure 0.2Pa + sputtering power 80 w.Compare sputtering coating with substrate,the hardness of sputtering coating reached the expected value.The organization of sputtering coating is more dense,compact,small granularity than the substrate.Performance is improved greatly than that of the substrate.