Development Of Al₂O₃-ZrB₂-C Composite

In the present paper, the development of A12O3-ZrB2-C composite is introduced. The composite will be applied to thermocouple's protection tubes which are a kind of measuring system for temperature of molten steel in ladle of continuous casting. The preparation of the composite, theaddition of additives and the relationship between the amount of additives and properties of the composite have been studied. Meanwhile, the behaviors of the thermal-shock resistance, the oxidation resistance and the slag resistance of the composite have also been revealed.The results indicate that the addition of ZrB2 can improve the mechanical properties, the thermal conductivity and the thermal-shock resistance of the composite; the addition of additives can promote the sintering and increase the density of the composite and reduce the apparent porosity of the composite. The most of all, additives can improve the behavior of the oxidation resistance and protect ZrB2.The experiment of the thermal-shock resistance indicates that the composite has good thermal-shock resistance with the cooperation of ZrB2 and C.The experiment of the oxidation resistance indicates that the oxidation's layer of additives and portion of ZrB2 can stop the further oxidation. The oxidation kinetic study for A12O3-ZrB2-C composite indicates that the oxidation process can be divided into three stages: the first stage is the prophase of oxidation, the second stage is the metaphase of oxidation, the time of the stage is so short that the data of the stage is not been got, the third stage is the anaphase of oxidation. The experiment of the slag resistance indicates that the addition of ZrB2 can improve the slag resistance of composite.