Effect of nano-graphite on mechanical properties and oxidation resistance of ZrB₂–SiC–graphite electrode ceramics

ZrB₂-based ceramic composites were prepared by spark plasma sintering using ZrB₂ powder prepared by molten salt method as raw material and SiC and nano-graphite as additives. The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB₂-based ceramic samples were investigated. The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB₂-based ceramic composites and improve the physical properties of the materials. The flexural strength of the ceramic sample with 8 vol.% nano-graphite reached 418.54 MPa, which was 53.14% higher than that of ZrB₂–SiC ceramic material (273.31 MPa), and its oxidation resistance was also significantly improved. It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB₂–SiC ceramic composites. Via prolonging its service life in application and promoting the development of ZrB₂-based ceramic composites, it is of great significance for clean steel smelting.