Ferrosilicon nitride plays a crucial role as an additive in the steelmaking process of special steels, significantly enhancing steel properties and broadening its application fields. Typically, Ferrosilicon nitride is produced through the nitridation reaction of ferrosilicon alloy. However, the details of this reaction process require further investigation and detailed elucidation. In this study, a combined approach of experimentation and simulation calculations was employed to deeply explore the N 2 adsorption on and reaction with the ferrosilicon alloy. The research findings indicate that granular α -Si 3 N 4 is primarily formed in the initial stage of the nitridation reaction. As the reaction progresses, the granular α -Si 3 N 4 gradually transforms into the long columnar β -Si 3 N 4 . β -Si 3 N 4 becomes the dominant form and continues to grow, with both its length and diameter constantly increasing. To comprehensively understand the kinetic characteristics of this reaction, we compared the fitting effects of various kinetic models, finding that the 1-D diffusion model provided the best fit. When the particle size increased from 0.075-0.1 mm to 0.3-0.5 mm, the apparent activation energy rose from 122.74 kJ·mol −1 to 130.92 kJ·mol −1 . An adsorption model of N 2 on ferrosilicon alloy was constructed based on first-principles calculations, and its adsorption behavior was subsequently analyzed. The results showed that the average adsorption energy of Si(111) for N 2 was −0.52 eV, while that of β -FeSi 2 (220) was 0.08 eV. These findings clarify the nitridation characteristics of ferrosilicon alloy and provide a solid theoretical foundation for their nitriding applications. • The morphological transformation from granular α -Si 3 N 4 to long columnar β -Si 3 N 4 during the nitriding process of ferrosilicon alloy. • With the progress of the nitriding reaction, Fe 4 N has a tendency to be further nitrided and transformed into Fe 3 N. • It was verified that the optimal kinetic fitting model for the nitriding of ferrosilicon alloy is a 1-D diffusion model. • Based on first-principles calculations, it was verified that the adsorption of N 2 on Si(111) is stronger than that on β -FeSi 2 (220).
Peng et al. (Wed,) studied this question.