Structure and properties of gradient PVD coatings deposited on the sintered tool materials
L. A. Dobrzanski; L. W. Zukowska
Journal of Achievements in Materials and Manufacturing Engineering
Abstract
Purpose: Investigate the structure and properties of sintered tool materials, including cemented carbides, cermets and oxide ceramics deposited with single-layer and gradient coatings (Ti, Al)N and Ti(C, N), and to determine the dependence between the substrate type, coating material or linear variation of chemical composition and the structure and properties of the obtained tool material. Design/methodology/approach: Analysis of the structure (SEM, TEM), analysis of the mechanical and functiona...Morel properties: surface roughness, microhardness tests, scratch tests, cutting tests. The Ti(C, N) and (Ti, Al)N gradient coating was investigated by XPS and AES method. X-ray qualitative phase analysis and the grazing incidence X-ray diffraction method (GIXRD) was employed to collect the detailed information about phase composition of investigated material's surface layer. Computer simulation of stresses was carried out in ANSYS environment, using the FEM method and the experimental values of stresses were determined basing on the X-ray diffraction patterns. Findings: Results of the investigation the influence of PVD coatings structure (single-layer or gradient) and kind on properties of coated tool materials. Coatings are characterized by dense, compact structure. The coatings were deposited uniformly onto the investigated substrate materials and show a characteristic columnar, fine-graded structure. The coatings deposited onto the investigated substrates are characterised by good adhesion and causes increasing of wear resistance. Gradient coatings are characterized by a linear change of chemical composition in the direction from the substrate to the coating surface. A more advantageous distribution of stresses in gradient coatings than in respective single-layer coatings yields better mechanical properties, and, in particular, the distribution of stresses on the coating surface has the influence on microhardness, and the distribution of stresses in the contact area between the coating and substrate has the influence on the adhesion of coatings. Practical implications: Deposition of hard, thin, gradient coatings on materials surface by PVD method features one of the most intensely developed directions of improvement of the working properties of materials. Originality/value: The grazing incidence X-ray diffraction method (GIXRD) and using the XPS and AES method in the investigated coatings were used to describe the gradient character of the coatings. The computer simulation is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution.
keywords:Materials; Tool materials; Gradient coatings; PVD; Finite Element Method
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