PLASMA NITRIDING IN LOW-PRESSURE IN AN ECR MICROWAVE PLASMA

Pure iron and 38CrMoAl samples have been plasma-nitrided by using elec tron cyclotron resonance (ECR)-microwave (2.45 GKz) N-2-H-2 discharge plasmas at low pressures (4-8 x 10(-2) Pa) and at a temperature of 500 degrees C. The experiment results show that both phases of gamma'- an d epsilon-iron nitrides are formed on the surface of the nitrided samp les. The thickness of the compound layer depends on the plasma nitridi ng time. After 4 h of nitriding, a 5-6-mu m iron nitride layer and 200 mu m diffusion layer are formed. The surface microhardness of the nit rided sample is increased. (C) 1998 Elsevier Science S.A.