DEPOSITION, PROPERTIES AND PERFORMANCE BEHAVIOR OF CARBIDE AND CARBONITRIDE PVD COATINGS

In recent years, significant improvements in the performance and quality of many machining processes have been achieved through physical vapour deposition hard coating of high speed steels and carbides. Under machining parameters with low machining process temperatures, e.g. in interrupted cutting, the Ti-C-N coating has proved particularly effective, firmly establishing itself in the market. However, industrial coating practice reveals that a variety of problems with the process and materials occur during deposition of Ti-C-N. Process instabilities are observed and the carbonitride films tend to spall. Coating properties also deteriorate markedly at low coating temperatures. A comprehensive study of this complex problem has indicated that the properties of the carbon-carrier gas used in the process greatly affect the process behaviour and coating properties. The paper presents the results of experimental work with four carbon-carrier gases. Ethane is characterized by its balanced reaction behaviour, as compared with acetylene, ethylene and methane.