涡轮增压器用无铅止推轴承材料摩擦学性能研究

Study on Tribological Properties of Lead-Free Thrust Bearing Material for Turbocharger

针对涡轮增压器用止推轴承材料的无铅化,采用粉末冶金工艺分别制备Cu Sn6.5P0.1无铅和Cu Sn10Pb10含铅止推轴承材料,并对比研究2种材料的微观组织结构及油润滑和乏油条件下材料的摩擦学性能。结果表明:微观组织结构上,Cu Sn6.5P0.1区别于Cu Sn10Pb10的硬基体(Cu合金基体)+软相(Pb)"两相"组织,呈"单相"组织;Cu Sn6.5P0.1的力学性能要优于Cu Sn10Pb10;在油润滑条件下,Cu Sn6.5P0.1和Cu Sn10Pb10的摩擦学性能基本一致,在乏油润滑条件下,Cu Sn6.5P0.1的摩擦因数更加平稳;乏油润滑条件下Cu Sn10Pb10形成了富Pb和Fe的润滑膜使摩擦因数保持平稳,Cu Sn6.5P0.1则形成Fe氧化物膜保证材料稳定的摩擦因数。Cu Sn6.5P0.1材料各项性能相当或优于Cu Sn10Pb10,满足涡轮增压器用止推轴承材料的无铅化要求。

According to the lead-free of thrust bearing material for the turbocharger lead-free CuSn6.5P0.1 and lead-containing CuSn10Pb10 thrust bearing materials were prepared by powder metallurgy process.Microstructures and tribological properties of two materials under oil-lubricated and oil lack condition were comparatively investigated.The results show that CuSn6.5P0.1 is consisted of single phase instead of two phases in CuSn10Pb10,which is composed of hard matrix(Cu-Sn matrix)and soft phase(Pb).The mechanical property of CuSn6.5P0.1 is better than that of CuSn10Pb10.Variation of friction curves of two materials under oil lubrication almost keep consistent.The stability of CuSn6.5P0.1 is better under oil lack condition.The stability of these materials could be remained due to generation of friction filmsunder oil lack condition.CuSn10Pb10 friction film was mainly composed of Pb and Fe,and iron oxide film formed CuSn6.5P0.1 friction film.As a consequence,CuSn6.5P0.1 material the performance is comparable or superior to CuSn10Pb10,which can meet operating requirements thrust bearing materials for turbochargers.