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离子软氮化是一项化学热处理新工艺,它渗速快、渗层质量好、表面硬度高、脆性小。对于4Cr14Ni14W2M_0奥氏体耐热钢,在同一温度下,离子软氮化的保温时间只是纯氨离子氮化的一半。而且试样的耐磨性提高两倍,耐蚀性提高一倍。该钢离子软氮化的表层组织主要是Fe_2N,Fe_3N和Cr_2(C,N)化合物。离子软氮化的渗层生长速度服从抛物线规律。氮在化合物层和扩散层的扩散系数分别为:D_Ⅰ=1.848×10~(-9)厘米~2/秒和D_Ⅰ=1.695×10~(-9)厘米~2/秒。氮在化合物层和扩散层的扩散激活能分别是:Q_Ⅰ=1.68×10~4卡/克分子和Q_Ⅰ=3.15×10~4卡/克分子。
Ionic nitriding is a new chemical heat treatment process, it seeps fast, permeable layer of good quality, high surface hardness, small brittleness. For 4Cr14Ni14W2M_0 austenitic heat-resistant steel, at the same temperature, the ion nitriding heat preservation time is only half of pure ammonia ion nitriding. Moreover, the wear resistance of the sample is doubled and the corrosion resistance is doubled. The soft nitrocarburized surface layer of the steel is mainly composed of Fe 2 N, Fe 3 N and Cr 2 (C, N) compounds. The growth rate of ion nitriding layer obeys the parabolic law. The diffusion coefficients of nitrogen in the compound layer and the diffusion layer are respectively D_I = 1.848 × 10 -9 cm -2 / sec and D_I = 1.695 × 10 -9 cm -2 / sec. The diffusion activation energies of nitrogen in the compound layer and the diffusion layer are respectively: Q_I = 1.68 × 10 ~ 4 cal / mol and Q_I = 3.15 × 10 ~ 4 cal / mol.