Plasma nitriding in low pressure in an ECR microwave plasma

Abstract

Pure iron and 38CrMoAl samples have been plasma-nitrided by using electron cyclotron resonance (ECR)-microwave (2.45 GHz) N 2–H 2 discharge plasmas at low pressures (4–8×10 −2 Pa) and at a temperature of 500 °C. The experiment results show that both phases of γ′- and ϵ-iron nitrides are formed on the surface of the nitrided samples. The thickness of the compound layer depends on the plasma nitriding time. After 4 h of nitriding, a 5–6-μm iron nitride layer and 200 μm diffusion layer are formed. The surface microhardness of the nitrided sample is increased.