氮化硅陶瓷球与轴承钢的微动摩擦磨损特性与损伤行为研究

Si₃N₄陶瓷球具有高承载、轻质、减振降噪以及化学性质稳定等特点，作为滚动体广泛用于高速高精密轴承中. 针对轴承球与滚道间的微动摩擦磨损行为，以不同烧结工艺制备的具有不同烧结助剂配方的Si₃N₄陶瓷球为研究对象，开展其与轴承钢的微动摩擦磨损试验，分析比较了Si₃N₄陶瓷球烧结工艺和助剂配方对摩擦状态与损伤程度的影响. 结果表明:无润滑条件下，5AlEr和3AlY助剂配方的Si₃N₄陶瓷球具有更稳定的摩擦状态和更低的磨损程度；提高气压烧结温度可缓解微动损伤行为，降低损伤程度；热等静压工艺的引入虽然进一步缓解磨损行为，但总体减弱了Si₃N₄陶瓷球的耐磨性能，从而为轴承用Si₃N₄陶瓷球制备工艺的优化提供依据. 并进一步揭示了Si₃N₄陶瓷球摩擦损伤、剥落和疲劳裂纹的损伤行为与磨粒磨损、黏着磨损和疲劳损伤，以及摩擦化学反应相结合的损伤机制. 

Fretting Friction and Wear Characteristics and Damage Behaviors of Si3N4 Ceramic Balls Sliding against Bearing Steel

Si₃N₄ ceramic balls are widely used in high speed and high precision bearings as the rolling bodies, because of their excellent performances, such as high bearing capacity, light weight, vibration and noise reduction, and stable chemical properties. As the rotating rolling bodies in service process, Si₃N₄ ceramic balls greatly reduce the friction behaviors in bearings, but there are still complex fretting friction and wear phenomena between the rolling bodies and ball tracks. The surface damage of Si₃N₄ ceramic balls caused by fretting wear, impact and fatigue may greatly increase the friction resistance, energy loss and loss of bearing accuracy. Meanwhile, that will accelerate the surface damage of themself, ball tracks and bearing retainer, thereby accelerating the bearing failure, or causing major mechanical accidents. Sintering additives are the essential parts of Si₃N₄ ceramics, which must have certain influence on the tribological properties of Si₃N₄ ceramic balls. In consideration of the fretting friction and wear behaviors between the bearing balls and ball tracks, the fretting friction and wear experiments of the Si₃N₄ ceramic balls with various sintering aids sintered under different processes were carried out by sliding against bearing steel, to analyze and compare the effects of sintering aids and sintering processes on the friction state and damage degree, by proposing a method for detecting surface damage degree of bearing balls. Results showed that the Si₃N₄ ceramic balls with 5AlEr and 3AlY aids exhibited more stable friction state and lower wear degree under non-lubricated conditions. Increasing sintering temperature of GPS process can alleviate the fretting damage behaviors and reduce the damage degree. The introduction of HIP technology could further alleviate the wear behaviors, but generally weakened the wear resistance of Si₃N₄ ceramic balls. The results provided a basis for the optimization of the formulas and preparation processes of Si₃N₄ ceramic balls as bearing rolling bodies. Meanwhile, the microstructures, morphologies and chemical composition of worn surfaces of Si₃N₄ ceramic balls and wear debris were characterized and analyzed by 3D profilometer, scanning electron microscope, elemental energy spectrometer and Raman spectrometer. And then the damage characteristics of friction damage, micro exfoliation and fatigue cracks of Si₃N₄ ceramic balls combined with the damage mechanisms consisting of abrasive wear, adhesive wear, fatigue damage and tribochemical reactions were further revealed.