沉积气压与脉冲频率对内花键齿表面Si-DLC薄膜性能的影响

Effects of Deposition Pressure and Pulse Frequency on Properties for Si-DLC Films Prepared on Surface of Internal Spline Tooth

花键齿严重的磨损失效制约了机械传动部件的可靠性和使用寿命,传统表面处理技术如渗碳、渗氮等无法满足花键齿减摩耐磨的需求。为提高内花键齿表面的耐磨性,采用等离子体增强化学气相沉积(PECVD)技术,利用空心阴极放电(HCD)产生的高密度等离子体,在大长径比内花键表面制备多层结构Si-DLC薄膜。分别研究薄膜制备过程中,沉积气压和脉冲频率对花键齿廓方向上薄膜的截面形貌、相结构、厚度均匀性和力学性能的影响。结果表明,沉积气压及脉冲频率是影响内花键齿表面薄膜性能及厚度均匀性的关键参数。沉积气压从8 Pa增加到10 Pa时,花键齿齿顶、齿中及齿根处的Si-DLC薄膜厚度均随之增大,而薄膜的硬度和弹性模量却随之降低。当脉冲频率从300 Hz增加到500 Hz时,花键齿表面薄膜厚度均随之减小。薄膜在花键齿廓方向上的厚度均匀性因等离子体密度增加,鞘层之间交叉重叠减少而变优。研究结果为耐磨强化涂层材料在动力传输系统上的发展与应用提供了基础。

Severe wear failure of spline tooth limits reliability and service life for mechanical transmission parts,traditional surface treatments like carburization and nitriding are incapable to meet the requirements of friction reduction and wear resistance for spline tooth.To improve the wear resistance of internal spline tooth,high density plasma generated by hollow cathode discharge(HCD)is used for the deposition of multi-layer Si-DLC films on inner surface of internal spline with a high aspect ratio by plasma enhanced chemical vapor deposition(PECVD).Effects of deposition pressure and pulse frequency on cross-section morphology,microstructure,thickness distribution and mechanical properties for films are studied,respectively.The results show that deposition pressure and pulse frequency are both significant parameters which affect the performance and thickness distribution for films prepared on internal spline tooth.The film’s thickness at tooth top,middle and root are all increased with the increasing deposition pressure from 8 Pa to 10 Pa,however,the hardness and elastic modulus are both decreased.The film’s thickness decreased while the pulse frequency increased from 300 Hz to 500 Hz.The thickness distribution along tooth profile optimized when the density of plasma increases which resulted reduced overlapping of cathode sheath.This paper provides foundations for development and application for wear-resistant coatings for power transmission system.