The Effects Of Rare Earth Oxides And Carbon Fiber On Properties Of Al₂O₃-C Refractory

The properties of Al₂O₃-C refractories and the status of rare earth oxides and carbon fiber applied to high temperature structure ceramics and refractories have been introduced. The effects of rare earth oxides and carbon fiber on the properties of Al₂O₃-C refractories have been investigated.The influences of Si/C ratio, different kinds of carbon (graphite, black carbon, and resin carbon), reaction temperature and addition of rare-earth oxides on formation of silicon carbide were studied. The results showed that rare-earth oxides additive can promote the formation of SiC to some extent. The optimal carbon content is excessive 20wt%.Rare-earth oxides can change the morphology of the SiCw and increase length/diameter ratio and addition of La2O3 is better than orthersThe effect of rare earth oxides on the microstructure and properties of Al₂O₃-C refractories were discussed. The results showed that rare-earth oxides can promote the sintering property of the Al₂O₃-C refractories and increase its bulk density and decrease its apparent porosity. Rare-earth oxides can also improve the mechanical properties and high-temperature properties of the samples because of the formation of SiCw in Al₂O₃-C refractories.The carbon-fiber can enforce the properties of Al₂O₃-C refractories.The results showed that the proper addition of carbon-fiber can improve the mechanical properties and high-temperature properties of the samples, and addition of 0.1wt% content of carbon-fiber is beneficial.The high temperature bending strength of the samples with 1wt% carbon-fiber contents reached to 7.6MPa at 1400℃.