Properties and microstructure evolution of unfired Al-Si incorporated Al2O3-C slide plate materials with trace nano-Al2O3 particles

For clean steel casting, reducing CO2 generation as well as energy saving, the unfired low carbon Al-Si incor-porated Al2O3-C slide plate materials were prepared in replacement of high temperature fired Al2O3-C slide plates with high carbon content. The effects of trace nano-Al2O3 particles on properties, phase composition and microstructure of the material were investigated. The results showed that trace nano-Al2O3 particles had a good filling effect, leading to an increase in the density of the dried specimens. The nano-Al2O3 particles with high reactivity could promote Al, Si reacting with C, CO, N-2 and forming more non-oxide Al4C3, AlN and SiC whiskers, thereby improving the hot strength and thermal shock resistance of the material. And the nano-Al2O3 particles easily reacted with SiO2 to form mullite containing dense surface, resulted in the improved oxidation resistance of specimens.