| Title |
Properties and Manufacture of the β-SiC-ZrB_2 Composited Densified by Liquid-Phase Sintering. |
| Authors |
신용덕(Sin, Yong-Deok) ; 주진영(Ju, Jin-Yeong) |
| Keywords |
Fracture toughness ; Elongated α-SiC ; Equiaxed ZrB_2 ; PTCR |
| Abstract |
The mechanical and electrical properties of the hot-pressed and annealed β-Sic+39vol.%ZrB_2 electroconductive ceramic composites were investigated as a function of the liquid forming additives of Al_2O_3+Y_2O_3(6:4wt%). In this microstructures, no reactions and elongated α-SiC grains with equiaxed ZrB_2, gains were observed between β-SiC and ZrB_2, and the relative density was over 97.6% of the theoretical density. Phase analysis of the composites by XRD revealedmostly of α-SiC(6H, 4H), ZrB_2, and weakly β-SiC(15R) phase. The fracture toughness decreased with increasing Al_2O_3+Y_2O_3 contents and showed the highest of 6.37MPa.m^{ fraction ane-half} for composite added with 4wt% Al_2O_3+Y_2O_3 additives at room temperature. The electrical resistivity increased with increasing Al_2O_3+Y_2O_3contents and showed the lowest of 1.51×10^{-4}Ω.cm for composite added with Al_2O_3+Y_2O_3 additives at 25°C. This reason is the increasing tendency of pore formation according to amount of liquid forming additives Al_2O_3+Y_2O_3. The electrical resistivity of the composites was all positive temperature coefficient resistance(PTCR) against temperature up to 700°C. |