Adhesion of PVD and CVD hard coatings as an essential parameter that determines the durability of coated tools

Abstract

Purpose: The work is connected with the current trend related to the modification of tool surfaces with PVD and CVD methods through the deposition of coatings to increase their durability. The research results of coated tools tests that are carried out in industrial conditions are presented in details. Design/methodology/approach: Structure, chemical and phase composition investigations related to the mechanical and tribological properties of coatings produced on tool substrates and analysis of the results are included. Investigations of the properties of deposited coatings on the following tool materials were made: high speed steels, hot work tool steel, sintered carbides and SiAlON tool ceramics. Findings: Interpretation of production tests results of coated tools and an analysis of the wear mechanisms of tool blades in relation to the properties of coatings and their adhesion, in particular characterized in the scratch test, were described. Research limitations/implications: Adhesion scratch test cannot be the only and final method of such evaluation. For example a direct comparison of the results of the scratch tests of coatings is possible when adhesion is being examined of different coatings yet on the same type of the substrate. Practical implications: Based on the adhesion test results using the scratch test, the suitability of the coatings produced on the cutting tools can be quickly assessed. Originality/value: It was sought those parameters which characterize the properties of coatings, ones which would permit to effectively/practically assess the performance of tools with coatings produced, with an exclusion or limitation of long-term and expensive durability tests of tools that are carried out in industrial conditions.