【摘 要】
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Recent studies have shown that interface tribochemistry, that is, the formation and breaking of chemical bonds across sliding interfaces, is closely related to the wear and friction behavior at the na
【机 构】
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School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, Chi
【出 处】
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第十一届全国表面工程大会暨第八届全国青年表面工程学术会议
论文部分内容阅读
Recent studies have shown that interface tribochemistry, that is, the formation and breaking of chemical bonds across sliding interfaces, is closely related to the wear and friction behavior at the nanoscale. In reality, under different relative humidity (RH) levels, the surface dangling bond density (SDBD) at sliding surfaces can vary greatly. In this study, we address these issues by studying the wear and frictional behavior of PCD sliding with Si3N4 sphere by controlling SDBD via changing the relative humidity levels in testing atmosphere (55%-85%RH and water lubrication conditions). The present work reveals insights into the effect of interface chemistry on the friction and wear, and it provides guidelines for effective antiwear design. With the increase of RH levels, a mechanism transition from an atom-by-atom to cluster detachments is observed. Remarkably, a fully saturated surface covered by water molecule lubricant film can exhibit a wearless tribological behavior in water lubrication condition. When water molecules are introduced in testing atmosphere, the silicon nitride surface can occur in hydrolysis reaction with the formation of the Si–O–Si bond across the sliding interface. And then, the hydration reaction can act on the Si–O–Si bond by forming Si-OH, which may cause different wear loss. The XPS measurement revealed that the ratio of Si-N/Si-OH/Si-O is increased with the increasing of relative RH levels, which can demonstrate that higher concentration water molecules larger Si-OH/Si-O ratio, thus, the wear loss increased with the increasing of RH levels. Consequently, different water molecule concentrations dependence on the wear loss has been systematic investigated via exploring the interfacial tribochemical reaction and mechanism of humidity dependence on wear of silicon nitride sliding against sintered polycrystalline diamond is demonstrated.
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