Effect of ion flux parameters on the rate of austenitic stainless steel nitriding in electron beam generated plasma

Abstract

Nitriding of metals in electron beam generated plasma provides change of ion current density j and ion energy E over a wide range, the constant temperature of a sample being sustained by change of electron beam parameters. Broad (100 cm2) electron beam (5-20 A, 60-500 eV) was generated by electron source with a plasma cathode. 12X18 10 stainless steel was nitrided at 500 during 1 h. Dependences of nitriding layer thickness on j (1,6-6,2 m/cm2), E (100-300 eV), pressure of Ar-N2 gas mixture (1-10 Pa) were obtained. Nitrided layer thickness was measured in cross-sections with the use of microhardness meter and SEM micropictures. The layer thickness decreases with the rate 4-5 microns per 100 eV with E growth and rises from 19 up to 33 microns with j increase. Character of nitriding rate dependence on j contradicts conclusions of the theory concerning restriction of the layer thickness by ion sputtering with j growth. The value of effective diffusion coefficient is an order of magnitude higher than the one known from literary data. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20843