Si_3N_4+Cの反応によるSiCウイスカー生成条件に関する考察

概要

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In order to obtain SiC whisker dispersed Si_3N_4, the reaction mechanism and the condition of SiC whiskerizing through the reaction between Si_3N_4+C was studied thermodynamically. In this work, Si_3N_4+C mixture was heat treated in 0.1 MPa of Ar at temperatures from 1350 to 1750℃. SiC whiskers were obtained in the powder mixture heated above 1600℃. By using the Si_3N_4 powder heat treated at 1100℃ for 24h in air, however, no SiC whiskers were obtained in the carbon mixed powder, indicating that the surface oxide of Si_3N_4 powder does not take part in the SiC whisker formation reaction. The experimentally measured nitrogen partial pressure during SiC wiskerizing was in good agreement with the equilibrium nitrogen partial pressure between Si and Si_3N_4, and it suggests that Si vapour is in equilibrium with Si_3N_4. Supersaturation for the carbothermal reduction of Si_3N_4 was calculated as a function of temperature. Supersaturation took value 10 to 20 during SiC whiskerizing.
社団法人日本セラミックス協会の論文
1998-07-01