Investigation of the influence of the manufacturing conditions and the design on the tribo-mechanical properties and residual stresses of PVD multilayer systems

PVD涂层多层体系中存在的残余应力对其最终的摩擦力学行为有很大影响。在以往的实验中，通过DCMS沉积不同的Ti/TiAlN多层体系，已经证明了高压缩残余应力的集中促进了涂层裂纹和剥落的产生。此外，残余压应力随DCMS沉积金属层厚度的增加而增加，从而影响化合物多层/基板的摩擦学和力学性能。我们认为这种行为是由于钛夹层的微观结构差异造成的。在此基础上，利用hiims技术有选择地改变Ti/TiAlN多层涂层的微观结构。将这些涂层与上述涂层进行比较，可以证明不同的微观结构和生长机制对PVD多层涂层残余应力的影响。为此，采用XRD对Ti/TiAlN HiPIMS涂层设计进行了评价，并通过x射线纳米束衍射分析生成了其残余应力深度分布图。此外，由于采用DCMS沉积的Ti/TiAlN涂层的残余应力高，摩擦力学响应差，因此提出了一种新的材料组合TiAlN/TiAlCN。由于碳的掺入，两种材料结合在一起，表现出很强的耐腐蚀性和高热稳定性，并改善了摩擦力学性能。此外，在热残余应力方面，两种新材料都是陶瓷，两者的热膨胀系数相似，这对它们的热膨胀系数也有很大影响。因此，系统中的热致残余应力显著降低。最后，通过纳米压痕实验、球盘实验、划痕实验和冲击实验等摩擦力学实验，得出多层体系中涂层结构和材料组合的结论，并与前人的实验结果进行比较。

The residual stresses present in the PVD coatings multilayer systems have high influence in their final tribo-mechanical behaviour. In previous experiments where different multilayer systems of Ti/TiAlN where deposited by means of DCMS, has been proved that the concentration of high compressive residual stresses promote the generation of cracks and spallation of the coatings. Additionally, was evidenced that compressive residual stresses increased with increasing thickness of the metallic interlayers deposited by means of DCMS, and thus, affecting tribological and mechanical properties of the compounds multilayer/substrate. It is assumed that this behavior is due to the microstructural differences of the Ti-interlayers.On this basis, the microstructure of Ti/TiAlN multilayer coatings should be varied selectively by means of HiPIMS technology. The comparison of these coating with the above mentioned, allow demonstrating the influence of different microstructures and growing mechanisms on the residual stresses of PVD multilayer coatings. For this purpose, Ti/TiAlN HiPIMS coating designs are evalu-ated by XRD and their residual stresses depth profiles generated through cross- sectional X-ray nanobeam diffraction analysis. Moreover, due to the high residual stresses and poor tribo-mechanical response of the Ti/TiAlN coatings deposited by means of DCMS, a new combination of materials are proposed for these section of the project, TiAlN/TiAlCN. The combination of two materials which exhibit great corrosion resistant and high thermal stability together with improved tribo-mechanical behavior, because of the incorporation of carbon. Besides, and in terms of thermal residual stresses, the similarity between the new two materials, both are ceramics, has a great effect in their thermal expansion coefficients, which are also similar. Thus, thermal induced residual stresses in the system are re-duced notably.Finally and to draw conclusions about the coating architecture and combinations of materials in multilayer systems, tribo-mechanical experiments as nanoindentation, ball-on-disk experiments, scratch tests and impact tests are conducted and compared between them and the results from previous experiments.