| Effect of Si/α-Si3N4 Ratio on the Shape of Silicon Nitride Particles Produced by SHS Method |
| Min-Sung Kim, Dong-Soo Park1, Byung-Dong Han1, Hai-Doo Kim1, Chan Park |
Dept. of Materials Science and Engineering, Pukyong Nat'l Univ.
1Ceramic Materials Group, KIMM |
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| ABSTRACT |
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Si and ${alpha}-Si_3N_4$ powder mixtures added with 3 wt% $Y_2O_3$ were reacted under 5 MPa nitrogen pressure. The reaction products contained ${alpha}-Si_3N_4$ particles with elongated shapes. Length and width of the elongated grains were the maximum when the starting powder mixture of 50 wt% Si - 47 wt% ${alpha}-Si_3N_4$ and 3 wt% $Y_2O_3$ was used. Aspect ratio of the elongated grains were between 4.4 and 5. When the starting powder mixture contained 70 wt% Si, large particles with irregular shapes appeared. Meanwhile, the reaction did not proceed when the starting powder mixture contained 30 wt% Si and less. The SHS product was easy to crush and the elongated particles obtained from the starting powder mixtures of 40 wt% Si - 57 wt% ${alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ and 50 wt% Si - 47 wt% ${alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ were good candidates for the seeds. |
| Key words:
SHS, Silicon nitride, Elongated grains |
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