Liu Y, Gubisch M, Spiess L, Schaefer J A
Institut für Physik und Zentrum für Mikro- und Nanotechnologien, Technische Universität, Ilmenau, PF 100565, Germany.
J Nanosci Nanotechnol. 2009 Jun;9(6):3499-505. doi: 10.1166/jnn.2009.ns23.
The transfer film on steel spheres formed in reciprocating sliding against nanocomposite coatings based on nanocrystalline WC1-x in amorphous carbon matrix is characterized and correlated with the tribological properties measured by a precision microtribometer. With the presence of transfer film, a coefficient of friction approximately 0.13 and a depth wear rate approximately 0.35 x 10(-10) m/N.Pass were obtained. The central zone of the transfer film covering approximately 25% of the Hertz contact area is intact while cracks and wear debris are found in the vast peripheral area. It is also heavily oxidized due to the absence of carbon, which is located at the peripherals and acts as lubricants. We propose that the oxidation of WC and adhesion of the oxides to the surface of sphere is the main mechanism for the buildup of the transfer films. With the thickening of the film, the internal stress increases. Under the shear stress, spalling and cracking of the transfer film take place. The overall tribological performance of the coatings is therefore a competing process of buildup and spalling of transfer films.
对在非晶碳基体中基于纳米晶WC1-x的纳米复合涂层上往复滑动形成的钢球表面转移膜进行了表征，并将其与精密微摩擦计测量的摩擦学性能相关联。在存在转移膜的情况下，获得了约0.13的摩擦系数和约0.35×10(-10) m/N·Pass的深度磨损率。覆盖约25%赫兹接触面积的转移膜中心区域完好无损，而在广阔的周边区域发现了裂纹和磨损碎屑。由于位于周边且起润滑剂作用的碳的缺失，转移膜也被严重氧化。我们认为WC的氧化以及氧化物在球体表面的粘附是转移膜形成的主要机制。随着膜的增厚，内应力增加。在剪切应力作用下，转移膜发生剥落和开裂。因此，涂层的整体摩擦学性能是转移膜形成和剥落的竞争过程。
