J Mater Sci Technol ›› 1992, Vol. 8 ›› Issue (2): 103-106.

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Stability of Phases in SiC and Si_3N_4 Whisker Formation

CHEN Shengqi ZHOU Yanchun XIA Fei ** Institute of Metal Research,Academia Sinica,Shenyang,110015,China+ To whom correspondence should be addressed.   

  • Received:1992-03-28 Revised:1992-03-28 Online:1992-03-28 Published:2009-10-10

Abstract: The stability of the phases in equilibrium is calculated and discussed in order to analyse and predict the reactions in SiC and Si_3N_4 whisker formation.Equilibria among SiC,Si_3N_4,Si_2N_2O,SiO_2 and the gas phase are evaluated at different C activity,N_2 pressure,and temperature.According to the phase stability diagrams,Si_3N_4 whisker was formed with the increase of N_2 pressure and decrease of C activity;SiC whisker was stable with the increase of C activity and decrease of N_2 pressure.In order to control the impure phases during the whisker formation,O_2 partial pressure is the most important factor.

Key words: whisker, phase stability, thermodynamic calculation