【摘要】 试验表明,08钢氮化时表面首先出现γ′,然后发生ε相的成核与成长。软氮化时首先形成的可能是Fe₃C+ε层,尔后在内侧生成（ε+γ′）层。ε晶粒呈柱状与试样表面垂直。ε的晶粒度与氮化时间有关。随着氮势变化,γ′分别有连续薄层、密集块状、分散的多边形等形态,γ′的形态及数量也和钢的含碳量有关。化合物层与扩散层交界处的组织比较复杂。表面疏松似与化合物层向空间方向生长有联系。耐磨试验与声发射试验表明,渗层成份及组织形态影响其性能。看来,通过控制炉气的氮势和碳势、控制化合物层的成份和组织,有可能获得性能最佳的渗层。另一方面,采用无公害的短时氮化代替软氮化也是有可能的。更多还原

【Abstract】 The experimental results has shown that within the surface layer,γ′ phase is formed first,and then ε phase starts to nucleate and grow during the nitriding of 08 steel.However,during nitrocarburizing,the （Fe₃C+ε） layer would be first formed and then （ε+γ′）layer is formed beneath.The grains of of ε phase exist: as columns perpendicular to the free surface of the specimen.The grain size of ε phase is related to the nitriding time. With change of carbon potential,the morphology of γ′ may be formed in a continuous thin layer or an intermittent thin layer,densely massive forms or dispersed polygons.The morphology and the amount of γ′ phase are also related to the carbon content of steel tested. The structures of the boundary between compound layer and diffusion layer are rather complex.It is likely that the surface porosity formed is related to the fact that the compound layer was expanded along the directions perpendicular to the specimen surfaces,both inward and outward. The present preliminary test has shown that the properties of specimen tested were affected by the compound layer composition and morpholoy of penetrating layer. The best properties of penetrating layer could be obtained through the controlling of nitrogen and carbon potential of the atmosphere used,chemical composition of specimen and structure of the compound layer formed.It is probable to adopt the short time nitriding without pollution to replace the nitrocarburizing.更多还原