Role of nano-ZrO2 powder in in-situ formation of ceramic whiskers in Al2O3-C slide plate materials

The effects of nano-ZrO2 powder on the evolution of phase composition and microstructure of Al2O3-C materials during firing have been investigated using tabular alumina, Si powder, Al powder, graphite and nano-ZrO2 powder as starting materials. The residual content of Al and Si gradually decreased with increasing temperature, and the added nano-ZrO2 facilitates the reactions involving Si and Al. The quantity of in-situ synthesized AlN and SiC whiskers exhibiting continuous interlocking networks increased gradually with temperature. Nano-ZrO2 facilitates more ceramic whiskers generated in samples, which play a strengthening and toughening role in the materials, thus improving the thermal shock resistance and high temperature strength of Al2O3-C materials. In addition, physical properties are improved due to the nano-ZrO2 filling the pores and increasing the density of materials.