钛合金基材表面粗糙度对Ti/TiN/Zr/ZrN多层膜性能的影响

为提高钛合金的抗冲蚀性能,采用真空阴极电弧离子镀技术在不同表面粗糙度(Ra)的TC4钛合金表面制备了Ti/TiN/Zr/ZrN多层膜。采用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、划痕仪和砂粒冲刷试验仪分析了多层膜的截面形貌、微观结构、厚度、显微硬度、结合力和抗砂粒冲刷性能。重点研究了基体表面粗糙度对多层膜的结合力和抗砂粒冲刷性能的影响。结果表明,所得Ti/TiN/Zr/ZrN多层膜厚度约为12μm,显微硬度大于3000 HV,能显著地提高TC4钛合金基材的抗砂粒冲刷性能。在相同工艺条件下,基体表面粗糙度越小,其表面膜层的结合力和抗砂粒冲刷性能越佳。为获得综合性能良好的Ti/TiN/Zr/ZrN多层膜,TC4钛合金基体的表面粗糙度必须控制在≤1.60μm。

Effects of surface roughness of substrate on properties of Ti/TiN/Zr/ZrN multilayer coatings

Ti/TiN/Zr/ZrN multilayer coatings were deposited on Cr_17Ni_2 steel substrates with different surface roughnesses by vacuum cathodic arc deposition method. Microstructure, micro-hardness, adhesion strength and cross-sectional morphology of the obtained multilayer coatings were investigated. The results show that the Vickers hardness of Ti/TiN/Zr/ZrN multilayer coating, with a film thickness of 11.37 μm, is 29.36 GPa. The erosion and salt spray resistance performance of Cr_17Ni_2 steel substrates can be evidently improved by Ti/TiN/Zr/ZrN multilayer coating. The surface roughness of Cr_17Ni_2 steel substrates plays an important role in determining the mechanical and erosion performances of Ti/TiN/Zr/ZrN multilayer coatings. Overall, a low value of the surface roughness of substrates corresponds to an improved performance of erosion and salt spray resistance of multilayer coatings. The optimized performance of Ti/TiN/Zr/ZrN multilayer coatings can be achieved provided that the surface roughness of Cr_17Ni_2 steel substrates is lower than 0.4μm.