Ionic nitriding of austenitic and ferritic steel with the aid of a high aperture hall current accelerator

Ionic implantation technologies play an important role for the surface modification of materials. Recently, a novel Hall current accelerator has been developed. The accelerator has a large aperture of 1400 mm and a power up to 10 kW. High ionic currents up to 1 mA/cm(2) permit to use the source both for ion implantation and for ionic cleaning of substrates. Various gases can be used for both purposes: argon, nitrogen, oxygen, etc. The current-voltage characteristics for nitrogen at various pressures are presented. The ionic nitriding of austenitic stainless steel and ferritic low-carbon steel has been studied. The influence of ionic current, energy of ions and implantation time are determined. The depth profiles measured with the aid of secondary-ion mass spectroscopy are presented. The hardness after ionic nitriding is characterized, the mechanism of the irradiation-enhanced nitrogen penetration in the austenitic stainless steel is discussed.