REPRODUCIBLE ARC-PVD PROCESS MANAGEMENT UNDER VARIOUS REACTIVE GASES

During the last few years, hard protective coatings on cutting tools or metal-forming dies have gained steadily increasing importance. The PVD processes in particular have found a wide range of applications, owing to their low coating temperatures. Reactive arc evaporation is a very efficient PVD process, but highly stable process management is needed to ensure reproducible deposition of new complex hard coatings on complex substrate geometries. The production of carbide and carbonitride coatings is particularly critical as compared with the deposition of nitrides. Detailed studies have therefore been made of typical problems. The paper describes the behaviour of various gas atmospheres in the arc-PVD process and discusses the resulting influences on cathode evaporation and coating deposition. Depending on the gas used or the process status required, it is necessary to control either gas pressure or gas flow. The paper also discusses the influence of a number of evaporator characteristics and a variety of process parameters on growth conditions for thin films. It shows that process parameters may need to be adapted to specific evaporator conditions in order to ensure constant process behaviour.