液氮介质中Si3N4/9Cr18配副摩擦磨损性能研究

超低温介质中工作的轴承由于不能采用润滑油或脂润滑,其球环材料配副摩擦磨损特性将对轴承的工作性能产生很大影响。采用球盘点接触形式,在5 N载荷和0.4 m/s相对滑动速度下试验研究了超低温全钢轴承和混合式轴承中9Cr18/9Cr18和Si3N4/9Cr18两种球环配副在常温干摩擦和液氮环境中的摩擦磨损性能。结果表明9Cr18/9Cr18配副在低温下由于粘着趋势减弱而使摩擦因数和磨损均低于常温下。Si3N4/9Cr18配副在低温介质中由于试件表面吸附、氧化和摩擦化学反应受到抑制使摩擦因数高于常温下,同样由于无摩擦化学磨损发生,而只是以脆性断裂为主,其磨损低于常温下。Si3N4/9Cr18在常温下摩擦因数低于9Cr18/9Cr18配副,而在低温下则高于9Cr18/9Cr18配副。2种环境中陶瓷/钢配副的磨损均小于相应条件下钢/钢配副的磨损。

Friction and Wear Behavior of Si3N4/9Cr18 Pairs in Liquid Nitrogen

Since no oil or grease lubrication can be used for the bearings which operating in cryogenic liquids,the friction and wear behavior between bearing balls and rings would play a great role on the operating performance of bearings.The friction and wear properties of 9Cr18/9Cr18 and Si3N4/9Cr18 pairs,which represented the materials of balls and rings in all-steel bearings and hybrid bearings,were studied at normal temperature and in liquid nitrogen with point contact between ball and disk at normal force of 5 N and sliding velocity of 0.4 m/s.The results show that the friction coefficient and wear of 9Cr18/9Cr18 in liquid nitrogen are lower than those at normal temperature because of the decreasing of adhesion tendency.When the pair of Si3N4/9Cr18 tested in liquid nitrogen,the adsorb and oxidization ability and tribochemistry reaction of material surfaces are hindered and no tribochemistry wear occurs.So friction coefficient is higher and wear,which exhibited mainly brittle fracture,is lower than those at normal temperature.The friction coefficient of Si3N4/9Cr18 is lower than that of 9Cr18/9Cr18 at normal temperature but the relationship is reversed in liquid nitrogen.The wear for Si3N4/9Cr18 is lower than that for 9Cr18/9Cr18 at both conditions.