Abstract
Surfaces of metals, such as Ta and Ti, have been changed successfully to a new type of ceramic layers having the compositional gradient by means of the plasma processing at high temperature above 900°C. Surfaces of Ta and Ti were transformed to thick layers of ceramics, i.e. TiC, TiN, TaC or TaN components, respectively, by carburizing or nitriding. Resultantly, a Vicker’s hardness of each modified sample surface remarkably increased over 3000 kg/mm2. The density of carbides or nitrides in the modified layer and at the interface was measured to decrease with depth. The width of interface was wide about 7 \\micron, in the case of TiC . Additionally, the irradiation of 20 MeV-electron beam to samples as the pretreatment before the plasma processing was effective to increase the thickness of modified layer.
