Function mechanism of Y ₂ O ₃ additive in silicon powder nitridation

Abstract Effect of sole Y ₂ O ₃ additive on the nitridation behavior of silicon powder was systematically studied using thermo gravimetry, differential thermal analysis, particle size analysis, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, scanning electron microscope and thermodynamic analysis in this paper. The thermo gravimetry results showed that Y ₂ O ₃ additive can significantly decrease the initial nitriding temperature and increase the nitriding rate. This phenomenon can be attributed to the much lower reaction temperature of the silica film and Y ₂ O ₃ additive than that of the silica film and silicon. In addition, Y ₂ O ₃ additive has little effect on the nitridation of silicon powder at 1300°C. However, it can obviously enhance the nitridation of silicon powder and the formation of β‐Si ₃ N ₄ at 1400°C, which is evidenced by the fact that the overall conversion increases from 58.1% to 100% and the fraction of β‐Si ₃ N ₄ in generated Si ₃ N ₄ increases from 7.9% to 68.2% with increasing the content of Y ₂ O ₃ additive from 0 to 10 wt%.