Abstract: In this paper, the effect of the micro-addition of race earth elements (RE) to the nitriding process on the diffusion kinetics and properties of 38CrMoAl steel were studied. The experimental results indicate: the nitriding process of 38CrMoAl is accelerated under the acting of activity and catalysis of RE, its rate of permeation is increased 25%～30%; the wear resistance and bending fatigue of specimens increases some too. The SEM energy spectum analysis denote: the RE La has been permeated with the nitrogen together, which improves the properties of surface layer through microalloying.

Key words: 氮化, 铬钼钢, 稀土元素