Evaluation of Local Mechanical Properties in Depth in MoDTC/ZDDP and ZDDP Tribochemical Reacted Films Using Nanoindentation
Evaluation of Local Mechanical Properties in Depth in MoDTC/ZDDP and ZDDP Tribochemical Reacted Films Using Nanoindentation
复制标题
使用纳米压痕评估 MoDTC/ZDDP 和 ZDDP 摩擦化学反应膜的局部机械性能
DOI：
10.1023/a:1016559807453
复制
发表时间：
2002
影响因子：
3.2
通讯作者：
Y. Yasuda
中科院分区：
文献类型：
--
作者：
Jiping Ye;M. Kano;Y. Yasuda
采用纳米压痕技术结合原位原子力显微镜（AFM）观察，研究了MoDTC/ZDDP和ZDDP摩擦膜在销-盘摩擦试验中摩擦系数明显不同的深度和近表面的局部力学性能。轻敲模式的AFM观察表明，MoDTC/ZDDP膜是比ZDDP膜粗糙得多。纳米压痕测试结果表明，MoDTC/ZDDP和ZDDP摩擦膜在离表面几个纳米的深度处具有不同的弹塑性，但除了表面区域外，两种膜的硬度和模量深度分布相同。相同的机械深度分布表明，这两种摩擦膜的功能梯度材料，也就是说，它们包括一个层的表面附近具有较低的硬度和模量，并提供润滑和基层具有较高的硬度和模量，并用于修改性能差异的接口。最重要的是，不同的弹塑性附近的摩擦膜表面显示，MoDTC/ZDDP摩擦膜具有较低的剪切屈服应力比ZDDP摩擦膜。本研究的结果表明，MoDTC/ZDDP薄膜表面下方存在一些固体润滑剂（例如MoS 2）可以降低边界摩擦系数。
Local mechanical properties in depth and near the surface of MoDTC/ZDDP and ZDDP tribofilms, which exhibited obviously different friction coefficients in a pin-on-disc test, were determined by using a nanoindentation technique combined with in-situ atomic force microscopy (AFM) observation. Tapping-mode AFM observation revealed that the MoDTC/ZDDP film was much rougher than the ZDDP film. Nanoindentation measurement revealed that the MoDTC/ZDDP and ZDDP tribofilms possessed different elasto-plasticities around a depth of several nanometers from the surface, although both films showed the same hardness and modulus depth distributions except in the surface area. The same mechanical depth distributions indicated that both kinds of tribofilm were functionally graded materials; that is, they consisted of a layer near the surface with lower hardness and modulus and providing lubrication and a base layer with higher hardness and modulus and serving to modify property differences at the interface. Most importantly, the different elasto-plasticities near the tribofilm surfaces revealed that the MoDTC/ZDDP tribofilm possessed lower shearing yield stress than the ZDDP tribofilm. The results of this study suggest that the presence of some solid lubricants such as MoS2 just below the MoDTC/ZDDP film surface reduced the boundary friction coefficient.