The tribological behaviors of silicon nitride (Si₃N₄) sliding against sintered polycrystalline diamond (PCD) were investigated by varying the relative humidity (RH) in the testing atmosphere. The results indicated that higher RH corresponds to higher wear loss of Si₃N₄ and the wear loss of PCD almost fell close to zero. Especially in the case of 85% RH, both a maximum wear loss of Si₃N₄ and a maximum friction coefficient were achieved. In addition, this study revealed insights into the interface chemistry effects on the wear behavior of Si₃N₄ under humidity. When water molecules were introduced into the testing atmosphere, the hydrolysis reaction occurred on the Si₃N₄ surface with the formation of the Si‐O‐Si bond across the sliding interface. And then, the hydration reaction dominated the process, during which Si‐OH was formed through the bond fracture of the Si‐O‐Si. The X‐ray photoelectron spectroscopy results showed that the ratios of Si‐OH/Si‐O and Si‐N/Si‐OH+Si‐O bonds increased as the relative RH levels increased. As a consequence, the wear loss of Si₃N₄ significantly increased. Thus, due to the hydrolysis and hydration reactions, the tribological behaviors of Si₃N₄ against sintered polycrystalline diamond can be essentially controlled via varying RH levels.

中文翻译：

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氮化硅通过改变湿度在烧结多晶金刚石上滑动的可控磨损行为

通过改变测试气氛中的相对湿度（RH），研究了氮化硅（Si ₃ N ₄）相对于烧结多晶金刚石（PCD）滑动的摩擦学行为。结果表明，较高的RH对应于较高的Si ₃ N ₄磨损损耗，而PCD的磨损损耗几乎下降到接近零。尤其是在相对湿度为85％的情况下，Si ₃ N ₄的最大磨损损失和最大摩擦系数都达到了。此外，这项研究还揭示了界面化学对Si ₃ N ₄磨损行为的影响的见解。在湿度下。当将水分子引入测试气氛时，水解反应在Si ₃ N ₄表面发生，并在整个滑动界面上形成Si-O-Si键。然后，水合反应主导了整个过程，在此过程中，Si-O-Si的键断裂形成了Si-OH。X射线光电子能谱分析结果表明，Si-OH / Si-O和Si-N / Si-OH + Si-O键的比例随着相对RH水平的增加而增加。结果，Si ₃ N ₄的磨损损失显着增加。因此，由于水解和水合反应，Si ₃ N ₄的摩擦学行为 基本上可以通过改变相对湿度水平来控制抗烧结多晶金刚石的性能。