Obrosov Aleksei, Sutygina Alina N, Volinsky Alex A, Manakhov Anton, Weiß Sabine, Kashkarov Egor B
Chair of Physical Metallurgy and Materials Technology, Brandenburg Technical University, Cottbus 03046, Germany.
Department of General Physics, National Research Tomsk Polytechnic University, Tomsk 634050, Russia.
Materials (Basel). 2017 May 20;10(5):563. doi: 10.3390/ma10050563.
In the current study, the properties of the CrN coatings deposited on the Inconel 718 superalloy using direct current reactive magnetron sputtering are investigated. The influence of working pressure on the microstructure, mechanical, and tribological properties of the CrN coatings before and after high-temperature hydrogen exposure is studied. The cross-sectional scanning electron micrographs indicate the columnar structure of the coatings, which changes from dense and compact columns to large columns with increasing working pressure. The Cr/N ratio increases from 1.4 to 1.9 with increasing working pressure from 300 to 900 mPa, respectively. X-ray diffraction analysis reveals a change from mixed hcp-Cr₂N and fcc-CrN structure to approximately stoichiometric Cr₂N phase. After gas-phase hydrogenation, the coating deposited at 300 mPa exhibits the lowest hydrogen absorption at 600 °C of all investigated coatings. The results indicate that the dense mixed cubic and hexagonal structure is preferential for hydrogen permeation resistance due to the presence of cubic phase with higher packing density in comparison to the hexagonal structure. After hydrogenation, no changes in phase composition were observed; however, a small amount of hydrogen is accumulated in the coatings. An increase of coating hardness and elastic modulus was observed after hydrogen exposure. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient up to 20%-30%. The best value of 0.25 was reached for hydrogen exposed CrN coating deposited at 300 mPa.
在当前研究中，对采用直流反应磁控溅射法沉积在Inconel 718高温合金上的CrN涂层的性能进行了研究。研究了工作压力对CrN涂层在高温氢暴露前后的微观结构、力学性能和摩擦学性能的影响。横截面扫描电子显微镜图像显示了涂层的柱状结构，随着工作压力的增加，其从致密紧凑的柱状结构变为粗大的柱状结构。随着工作压力从300 mPa增加到900 mPa，Cr/N比分别从1.4增加到1.9。X射线衍射分析表明，涂层结构从混合的hcp - Cr₂N和fcc - CrN结构转变为近似化学计量比的Cr₂N相。在气相氢化后，在300 mPa下沉积的涂层在所有研究涂层中于600 °C时表现出最低的吸氢量。结果表明，由于立方相的堆积密度高于六方结构，致密的立方和六方混合结构对氢渗透具有更好的抗性。氢化后，未观察到相组成的变化；然而，涂层中积累了少量氢。氢暴露后观察到涂层硬度和弹性模量增加。摩擦学测试表明，氢化导致摩擦系数降低达20% - 30%。在300 mPa下沉积的经氢暴露的CrN涂层达到了最佳的0.25摩擦系数值。
