The Structure and Mechanical Properties of Me/MeN/TiAlN Trilaminar Coatings Deposited by a Hybrid PVD Coating Technique

Abstract

The purpose of this study is to investigate the microstructure, mechanical properties and adhesion of Ti/TiN/TiAlN and Zr/ZrN/TiAlN trilaminar coatings, which were deposited on the high-speed steel substrate and cement carbide substrate by a hybrid PVD coating technique. X-ray diffraction technique (XRD) was used to reveal the structure of coatings. The fracture appearance of coatings was presented by scanning electron microscopy (SEM) and the element content was characterized by energy dispersive X-ray (EDX). Hardness and Yong's modulus were measured by using a nanoindentation technique and the adhesion of coatings was carried out with Rockwell HRC indentations. The results showed that all the coatings present a fcc B1 (NaCl type) structure and the TiN (111) is the dominant orientation. The TiAlN coatings with Ti/TiN interlayer presented a typical columnar structure, while the columnar structure became ambiguous in TiAlN coatings with Zr/ZrN interlayer. The chemical composition of TiAlN coatings is almost unacted on the inner interlayer. The hardness of the coatings on CC substrate is greater than that of on HSS substrate. However, the Ti/TiN/TiAlN coatings on HSS substrate has the maximum theH3/E*2ratio at 0.178 with a lowest hardness. The adhesion of Ti/TiN/TiAlN and Zr/ZrN/TiAlN coatings on CC substrate is remarkable greater than the adhesion of same coatings on HSS substrate.