CrCuAgN PVD Nanocomposite Coatings: Effects of Annealing on Coating Morphology and Nanostructure
CrCuAgN PVD Nanocomposite Coatings: Effects of Annealing on Coating Morphology and Nanostructure
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DOI：
10.1016/j.apsusc.2016.09.011
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发表时间：
2017-01
影响因子：
6.7
通讯作者：
Xingguang Liu;Chanon Iamvasant;Chang Liu;A. Matthews;A. Leyland
中科院分区：
文献类型：
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作者：
Xingguang Liu;Chanon Iamvasant;Chang Liu;A. Matthews;A. Leyland
采用脉冲直流非平衡磁控溅射法制备了CrCuAgN纳米复合PVD涂层。本研究着重于涂层后退火对涂层表面形貌、相组成和纳米结构的影响。在氮含量高达16原子%的涂层中，即使在300 °C和500 °C涂层后退火之后，铬也以金属Cr与N在过饱和固溶体中存在。在300 °C退火没有明显改变无氮和含氮涂层的相组成;然而，500 °C退火导致含氮涂层的显著转变。Ag聚集体的形成与（Cu + Ag）/Cr原子比（阈值约0.2）有关，而Cu聚集体的形成与（Cu + Ag + N）/Cr原子比（阈值约0.5）有关。主要的退火引起的变化是减少溶解度的Cu，Ag和N的Cr，和组合物改变从混合的超细纳米晶和部分非晶相构成的粗，但仍然主要是纳米晶结构。还发现，在足够的Cu含量（>12原子%）下，在适度高温（例如500 °C）下退火导致Cu和Ag的迁移（即使在相对低浓度的Ag下，≤ 3at.%）从涂层内部到涂层表面，这导致摩擦系数显著降低，与基底相比降低超过50%（半球形金刚石压头从0.31到0.14，氧化铝球配合面从0.83到0.40）。结果表明，除了Cu和Ag（在适当的浓度），含氮的铬是一个可行的策略，为发展的“自我补充”含银薄膜结构的温度依赖性固体润滑的要求或抗菌涂层应用。
CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also found that, with sufficient Cu content (>12 at.%), annealing at a moderately high temperature (e.g. 500 °C) leads to transportation of both Cu and Ag (even at relatively low concentrations of Ag, ≤3 at.%) from inside the coating to the coating surface, which resulted in significant reductions in friction coefficient, by over 50% compared to that of the substrate (from 0.31 to 0.14 with a hemispherical diamond indenter, and from 0.83 to 0.40 with an alumina ball counterface, respectively). Results indicate that the addition of both Cu and Ag (in appropriate concentrations) to nitrogen-containing chromium is a viable strategy for the development of ‘self-replenishing’ silver-containing thin film architectures for temperature-dependent solid lubrication requirements or antimicrobial coating applications.