Desulfurization phenomenon of Ni-base superalloy using a solid CaO was identified by adjusting the temperature of melt. Ni-base superalloy and NiS powder were heated together at 1400 °C, 1500 °C, and 1600 °C. Dense and porous CaO rods were inserted into the melts individually. After the rods were pulled out, CaO, CaS, and calcium aluminates were detected on the rods by X-ray diffraction analysis. Electron probe microanalysis showed that only Ca, O, Al, and S distributed at the melt/CaO interfaces. At 1500 °C and 1600 °C, Al and S were also detected at particle boundaries in the rods. S contents in the alloys decreased as the desulfurization time passed and the temperature was raised. There was no prominent correlation between the rod porosity and the S contents. The desulfurization reaction was suggested to be that CaO, Al, and S react to generate CaS and calcium aluminates. When the temperature is high enough, the calcium aluminates form a solid–liquid coexisting state. Effective diffusion coefficient, which shows the S diffusivity in the generated layer at the melt/CaO interface, depends on the temperature and can be expressed by the Arrhenius equation. It has been supposed that the desulfurization reaction mainly occurs on CaO, and a macroscale surface area controls the desulfurization rate.

通过调节熔体温度确定了使用固态CaO的Ni基高温合金的脱硫现象。Ni基高温合金和NiS粉末一起在1400℃，1500℃和1600℃下加热。将致密且多孔的CaO棒分别插入熔体中。拔出棒后，通过X射线衍射分析在棒上检测到CaO，CaS和铝酸钙。电子探针显微分析表明，只有Ca，O，Al和S分布在熔体/ CaO界面。在1500°C和1600°C下，在棒中的颗粒边界处也检测到Al和S。随着脱硫时间的增加和温度的升高，合金中的S含量降低。棒的孔隙率和S含量之间没有显着的相关性。有人认为脱硫反应是CaO，Al，和S反应生成CaS和铝酸钙。当温度足够高时，铝酸钙会形成固液共存状态。有效扩散系数取决于温度，可以通过Arrhenius方程表示，该系数表示熔体/ CaO界面生成层中S的扩散系数。可以认为脱硫反应主要在CaO上发生，并且宏观表面积控制了脱硫速率。