Preparation and application of ZrB2-SiCw composite powder for corrosion resistance improvement in Al2O3-ZrO2-C slide plate materials

摘要

ZrB2-SiCw (w-whisker) composite powders were synthesized by a microwave-assisted carbo/borothermal reduction method under argon atmosphere using zircon, boric acid, and activated carbon as starting materials. The optimized ZrB2-SiCw composite powder was obtained by adjusting heating temperature and amounts of boric acid and activated carbon. Further, the effect of the optimized ZrB2-SiCw composite powder addition on corrosion resistance of the Al2O3-ZrO2-C slide plate material against O-2 and Ca-treated steel was investigated. The results showed that the relative content of ZrB2-SiCw increased with increasing temperature. The excess of boric acid favored the formation of the ZrB2-SiCw, and the optimum amount of boric acid was overdosed to 30-45 wt %. The corrosion resistance and thermo-mechanical properties of Al2O3-ZrO2-C slide plate material could be improved effectively with 6 wt% ZrB2-SiCw composite powder addition, which was attributed to the excellent oxidation and corrosion resistance of ZrB2-SiCw composite powder. In addition, ZrB2 -SiCw could confer excellent thermal shock resistance and reduce the generation of cracks, ultimately preventing corrosive media from infiltrating into slide plates, further increasing corrosion resistance of the plates.