High temperature behavior of nanolayered CrAlTiN coating: Thermal stability, oxidation, and tribological properties
High temperature behavior of nanolayered CrAlTiN coating: Thermal stability, oxidation, and tribological properties
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DOI：
10.1016/j.surfcoat.2014.07.053
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发表时间：
2014-10
影响因子：
5.4
通讯作者：
T. Polcar;A. Cavaleiro
中科院分区：
文献类型：
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作者：
T. Polcar;A. Cavaleiro
硬质保护氮化物涂层常应用于在高温下工作的刀具。为了进一步开发和优化其性能，需要对其在高温下的结构、氧化、力学和摩擦学性能进行原位研究。在本研究中，我们重点研究了阴极电弧蒸发沉积在WC衬底上的纳米层CrAlTiN涂层的高温行为。采用电子探针显微分析和x射线光电子能谱（XPS）对涂层的化学成分和键合状态进行了表征。利用x射线衍射分析了沉积态和退火态样品的结构。采用划痕试验研究了材料的附着力，采用纳米压痕深度传感技术研究了材料的力学性能。这项工作的主要目的是在20-800°C的温度范围内，用高温摩擦计（销盘式）测试氧化铝球的摩擦和磨损性能。采用聚焦离子束制备磨迹截面，透射电镜分析；用XPS（化学深度剖面）和拉曼光谱对磨损轨迹进行了研究。涂层表现出优异的热稳定性和耐磨性。摩擦在500°C时达到最大值，然后下降，而磨损率在600°C时可以忽略不计，然后在更高温度下显着增加。即使在最高温度下，磨损表面的氧化程度也低得惊人，证实了氧化试验的结果。确定的主要磨损机制是抛光结合纳米级薄涂层分层；纳米多层材料是阻碍垂直裂纹扩展的重要因素。
Hard protective nitride coatings are often applied to cutting tools operating at high temperature. To further develop and optimize their performance, in-situ investigation of structure, oxidation, mechanical and tribological properties at elevated temperature is required. In this study we focus on the high temperature behavior of a nanolayered CrAlTiN coating deposited on WC substrates by cathodic arc evaporation. The coating's chemical composition and the bonding state were evaluated by electron probe microanalysis and by X-ray photoelectron spectroscopy (XPS). The structure of as-deposited and annealed samples was analyzed using X-ray diffraction. The adhesion was investigated by scratch test and the mechanical properties were studied by depth sensing nanoindentation. The main objective of this work was to have a detailed analysis of friction and wear properties tested by high temperature tribometer (pin-on-disc) with alumina balls as counterparts in the temperature range of 20–800 °C. Selected wear track cross-sections were prepared by focused ion beam and analyzed by transmission electron microscopy; the wear track was investigated as well by XPS (chemical depth profile) and by Raman spectroscopy. The coating showed an excellent thermal stability and wear resistance. The friction reached a maximum at 500 °C and then decreased, whereas the wear rate was negligible up to 600 °C and then increased significantly for higher temperatures. Oxidation of the worn surfaces was surprisingly low even at the highest temperature corroborating results of oxidation tests. The main identified wear mechanism was polishing combined with a nanoscale delamination of thin coating layers; nanoscale multilayer proved to be a vital factor blocking vertical crack propagation.