The development of an electroconductive SiC-ZrB2 ceramic heater through spark plasma sintering

Abstract

The SiC-ZrB2 composites were fabricated by combining 30, 35, 40 and 45vol.% of Zirconium Diboride (hereafter, ZrB2) powders with Silicon Carbide (hereafter, SiC) matrix. The SiCZrB2 composites, the sintered compacts, were produced through Spark Plasma Sintering (hereafter, SPS), and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-ZrB2 composites was examined. Reactions between β-SiC and ZrB2 were not observed via X-Ray Diffractometer (hereafter, XRD) analysis. The relative density of the SiC+30vol.%ZrB2, SiC+35vol.%ZrB2, SiC+40vol.%ZrB 2, and SiC+45vol.%ZrB2 composites were 88.64%, 76.80%, 79.09% and 88.12%, respectively. The XRD phase analysis of the sintered compacts demonstrated high phase of SiC and ZrB2 but low phase of ZrO 2. Among the SiC-ZrB2 composites, the SiC+35vol.%ZrB 2 composite had the lowest flexural strength, 148.49MPa, and the SiC+40vol.%ZrB2 composite had the highest flexural strength, 204.85MPa, at room temperature. The electrical resistivities of the SiC+30vol.%ZrB2, SiC+35vol.%ZrB2, SiC+40vol.%ZrB 2 and SiC+45vol.%ZrB2 composites were 6.74x10 -4, 4.56x10-3, 1.92x10-3, and 4.95x10 -3-cm at room temperature, respectively. The electrical resistivities of the SiC+30vol.%ZrB2, SiC+35vol.%ZrB2 SiC+40vol.%ZrB2 and SiC+45[vol.%]ZrB2 composites had Positive Temperature Coefficient Resistance (hereafter, PTCR) in the temperature range from 25 °C to 500°C. The V-I characteristics of the SiC+40vol.%ZrB2 composite had a linear shape. Therefore, it is considered that the SiC+40vol.%ZrB2 composite containing the most outstanding mechanical properties, high resistance temperature coefficient and PTCR characteristics among the sintered compacts can be used as an energy friendly ceramic heater or electrode material through SPS.