| Title |
Effects of Boride on Microstructure and Properties of the Electroconductive Ceramic Composites of Liquid-Phase-Sintered Silicon Carbide System |
| Authors |
신용덕(Shin, Yong-Deok) ; 주진영(Ju, Jin-Young) ; 고태헌(Ko, Tae-Hun) |
| Keywords |
YAG(Al_5Y_3O_{12}) ; Liquid-Phase-Sintered(LPS) ; Electroconductive Ceramic Composite ; PTCR ; Transition Metal TiB_2 ; ZrB_2 |
| Abstract |
The composites were fabricated, respectively, using 61[vol.%] SiC-39[vol.%] TiB_2 and using 61[vol.%] SiC-39[vol.%] ZrB_2 powders with the liquid forming additives of 12[wt%] Al_2O_3+Y_2O_3 by hot pressing annealing at 1650[°C] for 4 hours. Reactions between SiC and transition metal TiB_2, ZrB_2 were not observed in this microstructure. The result of phase analysis of composites by XRD revealed SiC(6H, 3C), TiB_2, ZrB_2 and YAG(Al_5Y_3O_{12}) crystal phase on the Liquid-Phase-Sintered(LPS) SiC-TiB_2, and SiC-ZrB_2 composite. β rightarrowα-SiC phase transformation was occurred on the SiC-TiB_2 and SiC-ZrB_2 composite. The relative density, the flexural strength and Young's modulus showed the highest value of 98.57[%], 249.42[MPa] and 91.64[GPa] in SiC-ZrB_2 composite at room temperature respectively. The electrical resistivity showed the lowest value of 7.96×10^{-4}[Ω·cm] for SiC-ZrB_2 composite at 25[°C]. The electrical resistivity of the SiC-TiB_2 and SiC-ZrB_2 composite was all positive temperature coefficient resistance (PTCR) in the temperature ranges from 25[°C] to 700[°C]. The resistance temperature coefficient of composite showed the lowest value of 1.319×10^{-3}/[°C] for SiC-ZrB_2 composite in the temperature ranges from 100[°C] to 300[°C] Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites. |