Effects of Hydrogen and Temperature on the Kinetics of the Fluidized‐Bed Nitridation of Silicon

Silicon nitride was produced via direct nitridation of silicon powder, using nitrogen with 10–40 vol% hydrogen, in a fluidized‐bed reactor, 55 mm in diameter, operated at temperatures in the range of 1200–1390°C. Hydrogen enhanced the nitridation of silicon toward its completion. The overall conversion of silicon as well as the yield of α‐silicon nitride increased with an increase in reaction temperature, while the yield of β‐silicon nitride decreased. In nitridation at 1300°C with 40 vol% hydrogen in nitrogen, 99% of silicon was nitrided in 24 h with a yield of α‐silicon nitride of about 90% in the product. When the reactor temperature was raised stepwise from 1300° to 1390°C along with the progress of nitridation, 99% of silicon was nitrided in 2.5 h and 85% of the product was α‐form.