Effects of SiC polymer precursor and Zn composite powders on properties of Al2O3-C unfired slide plate ma-terials
This work aims at improving the medium-and low-temperature strength of Al2O3-C unfired slide plate materials.Sucrose,nickel nitrate hexahydrate,ethyl orthosilicate and oxalic acid aqueous solution with the mass ratio of 1∶0.15∶2.7∶0.03 were added to ethanol aqueous solution in turn,and dried at 110 ℃ for 18 h,obtaining SiC polymer precursor.Then,tabular corundum,α-Al2O3 micropowder and flake graphite were used as the main raw materials,added with the SiC polymer precursor and Zn powder,pressed at 150 MPa into green bodies of 150 mm×25 mm×25 mm,cured at 180 ℃ for 24 h,and then heat treated at 600,800,1 000,1 200 and 1 400 ℃ for 3 h under carbon embedded conditions.The effects of the SiC poly-mer precursor and Zn powder on the properties of Al2O3-C materials were studied.The results show that the Al2O3-C material has the optimal comprehensive performance when adding 4.5％SiC polymer precur-sor and 1.5％Zn powder;at low temperatures,Zn powder melts and forms metal bonding phases in the material system;at medium temperatures,the pyrolysis reaction of the SiC polymer precursor and the catal-ysis of Zn powder after evaporation make the system form SiC fiber bonding phases.They work together to give Al2O3-C unfired slide plate material high medium-and low-temperature strength,which overcomes the failure problem caused by the low strength in application.
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