| Title |
Mechanical, Electrical Properties and Manufacture of the β-SiC-ZrB_2 Electroconductive Ceramic Composites by Pressureless Sintering |
| Authors |
신용덕(Shin, Yong-Deok) ; 권주성(Kwon, Ju-Sung) |
| Keywords |
Electroconductive ceramic composites ; Pressureless sintering ; Fracture toughness ; PTCR |
| Abstract |
The effect of Al_2O_3 additives to β-SiC+39vol.%ZrB_2 electroconductive ceramic composites by pressureless sintering on microstructural, mechanical and electrical properties were investigated. The β-SiC+39vol.%ZrB_2 ceramic composites were pressureless sintered by adding 4, 8, 12wt.% Al_2O_3 powder as a liquid forming additives at 1950^{ cire}C for 1h. Phase analysis of composites by XRD revealed mostly of α-SiC(6H), ZrB_2 and weakly α-SiC(4H), β-SiC (15R) phase. The relative density of composites was lowered by gaseous products of the result of reaction between β-SiC and Al_2O_3, therefore, porosity was increased with increasing Al_2O_3 contents, and showed the maximum value of 1.4197MPa.m^{1/2} for composite with 4wt.% Al_2O_3 additives. The electrical resistivity of β-SiC+39vol.%ZrB_2 electroconductive ceramic composite was increased with increasing Al_2O_3 contents, and showed positive temperature coefficient resistance (PTCR) in the temperature range of 25^{ cire}C to 700^{ cire}C. |