CERAMIC CATHODES FOR ARC-PHYSICAL VAPOR-DEPOSITION - DEVELOPMENT AND APPLICATION

Cathodes for reactive and non-reactive d.c.-arc physical vapour deposition were developed using sintering and high-pressure HIP techniques and commercial TiB2 powders. High-purity basic materials were doped with traces of various additives to improve HIP processing behaviour, resulting in pycnometric density, thermal and electrical conductivity beneficial to arc evaporation. Examinations of thermal and electrical properties, density and homogeneity were carried out on cathode materials, which were previously tested in arc-evaporation equipment with respect to various parameters (particle emission, thermal and electrical behaviour, spot movement characteristics, bias current, behaviour under reactive and non-reactive gas atmospheres of various pressures). Tests revealed a dependence between physical properties of cathode material and behaviour during evaporation testing, with good results for thermally and electrically conductive materials of high density. Furthermore, coatings (reactive Ti-B-N as well as non-reactive Ti-B) were deposited onto several substrates with cathodes that showed good results in previous evaluation tests. The coatings were analysed by measuring the deposition rate, microhardness, critical scratch load, and structural parameters (using X-ray diffractometry as well as REM). The dominant coating properties were high hardness and low droplet yield at favourable deposition characteristics.