TC4合金表面磁控溅射W-Al-N复合膜的摩擦磨损和高温抗氧化性能

Friction-Wear and High Temperature Oxidation Resistance of W-Al-N Films Deposited on TC4 Alloy by Reactive Magnetron Sputtering Technique

目前,在WN中加入Al制备多元复合膜的研究国内外报道较少。通过射频磁控溅射法,以不同Al靶功率在Si(100)和TC4合金上制备了不同Al含量的W-Al-N复合膜。采用扫描电镜、能谱仪、X射线衍射仪、纳米压痕仪(CSM)、摩擦磨损试验机、高温氧化试验研究了W-Al-N复合膜的微结构、力学性能、摩擦磨损性能及高温抗氧化性能。结果表明:随着Al含量的增加,W-Al-N复合膜的择优取向发生变化,(111)和(220)衍射峰逐渐消失,复合膜主要呈(200)择优取向生长;复合膜的硬度先增加后减小,当Al含量为32.40%(原子分数,下同)时硬度达到最大值37 GPa,此时表征复合膜抵抗塑性变形能力的变量H^3/E^(*2)也达到最大值0.308;室温下,随Al含量的增加,W-Al-N复合膜的摩擦系数与单层WN薄膜的相比变化不大,磨损率先降低后增大,在硬度最大处得到磨损率最低值9×10^(-9)mm^2/N;W_(0.676)Al_(0.324)N复合膜的摩擦系数在200℃时降低,随后随温度的升高先增大后减小;Al的加入提高了复合膜的高温抗氧化性能,起始氧化温度由WN单层膜的400℃提高到复合膜的800℃。

W-Al-N composite films with different Al contents were deposited on silicon(100) wafers and TC4 alloy by reactive magnetron sputtering technique.The microstructures,mechanical properties,friction-wear properties and high temperature oxidation resistance were investigated by SEM-EDS analysis,X-ray diffraction,nano-indentation,friction wear testing machine and oxidation test at high temperature.Results indicated that(200) preferred orientation was formed and the hardness of the films was increased and then decreased with the increase of Al content.The maximum value of hardness was 37 GPa when the Al content was 32.40%and H^3/E^(*2) reached the maximum value(0.308).At room temperature,friction coefficient of W-Al-N films was similar to that of WN films whereas the wear rate was decreased firstly and then increased with increasing Al content.The minimum value of the wear rate was 9×10^(-9)mm^2/N under the maximum value of hardness.The friction coefficient of W_(0.676)Al_(0.324)N composite films was decreased to 0.332 1 when the temperature reached 200℃.After that,the friction coefficient was increased and then decreased.The adding of Al improved the high temperature oxidation-resistance of the composite films and the initial oxidation temperature was improved to 800℃,compared with 400℃ for the WN films.