Enhancement and evaluation of strength stability of low-carbon Al2O3-C refractories based on ceramic phase distribution modulation

The performance stability of low-carbon Al2O3-C refractories combined with in-situ ceramics restricts their practical application. In this paper, carbon-coated corundum was prepared to adjust the distribution of in-situ ceramic phases in Al2O3-C refractories and improved the properties, and Weibull distribution function analysis was used to evaluate the reliability and stability of the mechanical properties of the modified refractory. The results demonstrated that the surface of corundum powder had a better carbon coating effect under the catalyst. Compared with the ordinary corundum powder, the introduction of catalytically modified corundum powder not only enhanced the strength of matrix-aggregate connection inside the low-carbon Al2O3-C refractories, and improved the density and stress transfer ability; but also played a positive role in enhancing mechanical reliability and stability, and the high-temperature modulus of rupture of the refractories increased by 60.36 %. The analysis and fitting of the three-parameter Weibull distribution function on the cold crushing strength results showed that the introduction of catalytically modified corundum powder increased the Weibull modulus of the refractories by 56.42 % and the critical strength by 19.53 %, indicating that the refractories had better safety and reliability in the actual use process.