| Carbon composite refractory material is widely used due to its good performance.But, the strength, thermal shock resistance and the erosion performance are decreasedsharply because the oxidation of graphite makes the structure of material loose. In orderto solve the problem of the oxidation of graphite in material, the method of adding metalAl as antioxidants is commonly used. The Al generates AlN and Al3C4generates Al2O3finnally with the added graphite and atmosphere gas N2. These reactions can improve thedensity of refractory, resistance and strength. On the other hand, the carbon compositerefractory added Al can generate AlN and Al3C4when the material heated and it will behydrated even damaged. Especially in the intermittent operated furnace and chamfer oflower RH whicn used unshaped refractory for the repairing parts, it will cause thehydration and damage markedly when these parts exposed to water steam.The effect of refractory microstructure, phase composition and properties of theTiO2adding are studied. Firstly, the experience studies the thermal stability of TiO2athigh temperature.Secondly the experiment which takes C and Al as raw material, TiO2asaddition, studies the effect of the material’s microstructure and phase composition. Theresults show that the AlN and Al3C4are generated at800℃,but TiO2dose not participatein the reaction; during1000℃and1200℃,the TiO2and Al2O3are generated. At thesame time the Al-O-C compounds is generated with Al3C4and Al2O3; AlN and Al3C4andAl-O-C compounds reduce at1400℃because of the oxidation action. Finnally, the effectof TiO2addtion on the material’s performances is studied. The results show that oxidationresistance can be improved when1%~3%TiO2is added. High flexural strength can beimproved when0.5%~1%TiO2is added and hydration resistance can be improved whenTiO2is added more and more,because the AlN or Al3C4which are easily hydrateddecrease due to the reaction between TiO2and Al. |
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