本文研究了在气体氮化渗剂中加入微量稀土元素对渗层组织和疲劳性能的影响。结果表明:稀土在氮化时被渗入到钢的表层起了微合金化作用,改善了渗层组织,稀土氮化处理后的弯曲疲劳极限,较普通氮化处理的有所提高。借助于扫描电镜观察,探讨了氮化层疲劳的机制。 In this paper, the effects of adding rare earth elements on the microstructure and fatigue properties of infiltrated layers were investigated. The results show that the rare earth is infiltrated into the steel surface during nitridation and plays a role of micro-alloying, which improves the bending fatigue limit of nitrided layer and nitrided layer, which is higher than that of ordinary nitrided layer. With the help of SEM observation, the mechanism of fatigue of nitride layer was discussed.