钐铁合金熔体渗氮实验研究

Experimental Study on Nitriding of Sm-Fe Melt

采用静置渗氮与底吹氮气渗氮两种工艺对钐铁熔体进行渗氮,通过XRD、SEM、EDS等手段分别研究渗氮合金样品的物相、形貌及成分,对比了两种工艺的渗氮效果。结果表明,钐铁合金熔体静置渗氮过程中,表面易形成高熔点难熔物质氧化钐,由于氧化钐覆盖在钐铁合金表面阻碍了N原子向熔体内部扩散,静置渗氮法未能达到理想的渗氮效果;底吹氮气渗氮试样的Sm_2Fe_(17)相中存在N元素,同时Sm_2Fe_(17)相主峰向小角度方向发生偏移,表明N原子进入Sm_2Fe_(17)相中,且渗氮效果良好。

The static nitriding and bottom-blown nitrogen nitriding processes of Sm-Fe melt were re- searched. The phase, morphology and composition of nitrided alloy samples were investigated through XRD,SEM and EDS, respectively. And the effects of the two nitriding processes were compared. The results show that during static nitriding of Sm-Fe alloy melt,the surface of the sample is easy to form highmelting-point refractory Sin2O3. Sm2O3 covers Sm-Fe alloy surface to hinder the diffusion of N atoms into the melt,and therefore the static nitriding method fails to achieve the desired nitriding effect. The nitrogen element is found in Sm2Fe17 phase of the alloy sample after bottom-blown nitrogen nitriding,and the main peak of Sm2Fe17 phase shifts to a smaller angle,indicating that N atoms enter Sm2Fe17 phase and the nitriding effect is good.