类金刚石薄膜对轴承钢表面机械性能和滚动接触疲劳寿命的影响

Effect of diamond-like carbon films on the bearing steel surface mechanical properties and rolling contact fatigue life

使用等离子体浸没离子注入与沉积(PⅢ&D)技术在轴承钢基体表面合成类金刚石(DLC)薄膜,研究了薄膜的结构和性能.结果表明,所制备的DLC薄膜主要是由金刚石键(sp^3)和石墨键(sp^2)组成的混合无定形碳,且sp^3键含量大于10%.DLC膜层致密均匀,与基体结合良好.DLC膜具有很高的硬度和杨氏模量,分别达到40 GPa和430 GPa;其最低摩擦系数由基体的0.87下降到0.2.被处理薄膜试件在90%置信区间下的L_(10)、L_(50)、L_a和平均寿命L较基体分别延长了10.1倍、4.2倍、3.5倍和3.4倍.PⅢ&D轴承钢滚动接触疲劳寿命的分散性得到了显著改善.

Microstructure and properties of plasma immersion ion implantation and deposition （PIII＆D） diamond-like carbon （DLC） films on bearing steel substrate were investigated. PIII＆D DLC consists of a mixture of amorphous and crystalline phases, with a variable ratio of sp^2/sp^3 carbon bonds, and the sp^3 bonds content more than 10%. The DLC film has extremely smooth area, good adhesion, high uniformity and efficiency of space filling over large areas. The nanohardness （H） and the elastic modulus （E） of DLC films measurement indicates that the maximum H（E） value is 40 GPa （430 GPa）, increases by 263.6% （95.5%）. The friction and wear behaviors and rolling contact fatigue （RCF） life of these samples have also been investigated by ball-on-disc and three-ball-rod fatigue testers. Results show that the friction coefficient decrease from 0.87 to 0.2; the L10, L50, La and mean life L of treated sample in 90% confidence level increases by 10.1, 4.2, 3.5 and 3.4 times, respectively. The RCF life scatter extent of treated samples is improved significantly.