Combined Effect of Aluminum Content and Layer Structure on the Oxidation Performance of Ti_1-xAl_xN Based Coatings

Jihua Peng¹，Chengxi Wang¹

1. School of Materials Science and Engineering,South China University of Technology

摘 要：TiN,Ti_1-xAI_xN single layer coatings and TiN/Ti_1-xAI_xN multilayer coatings were deposited on SKH51 tool steel substrate by arc ion plating.The coatings were annealed in air to study the effect of aluminum and film structure on the oxidation performance.The surface morphology and structure were characterized by scanning electron microscopy and X-ray diffraction.The element distribution on the cross section was analyzed by electron probe microscopy.It is found that the oxidation resistance of these Ti_1-xAl_xN based coatings is mainly attributed to aluminum content in them.In comparison with the Ti_1-xAl_xN single layer coating,the TiN layer inserting into the Ti_1-xAl_xN in a multilayer coating increases the tendency of Ti diffusion toward the surface and forms a Ti-enriched top surface oxide layer,thus degrades the oxidation resistance.As far as the oxidation resistance is concerned in this study,Ti_0.33Al_0.67N single layer coating performs the best among all coatings.The kinetic of oxidation behavior of all coatings presents two definite stages.One is a slow oxidation growth which conforms to parabolic law,and the other presents severe mass gain with oxidation duration.The annealing time for severe oxidation initiation is responsible to Fe₂O₃formation in the oxide scale.

关键词：