Principally, main components of refractory materials consist of oxides such as MgO, CaO, Al2O3, SiO2, ZrO2, and Cr2O3 and their application in many different high-temperature processes is well established. To optimise specific refractory properties, in certain cases the oxides are combined with non-oxides, the most common examples being carbon, SiC, borides, and elements like Al and Si (i.e., antioxidants). Besides these established non-oxides, numerous alternative phases like carbides, nitrides, oxycarbides, oxynitrides, and oxycarbonitrides exist that enhance refractory material behaviour.
 
Many phases within the Me-O-C-N system show noteworthy intrinsic properties such as high thermal conductivities, high melting points, low sintering, poor wetting by slags, self-healing capabilities, and ductility. For example, the layered ternary carbide and nitride MAX phases exhibit an unusual combination of both metallic and ceramic characteristics under various conditions. Like ceramics they show high strength, high melting points, thermal stability, and good oxidation resistance; however, they also demonstrate the metallic characteristics of high thermal and electrical conductivity, machinability, as well as fatigue and thermal shock resistance. Therefore, RHI Magnesita initiated a research program to determine the impact of MAX phases on refractory properties. As these materials are not commercially available in large quantities, initially it was necessary to develop an upscaled electric arc furnace synthesis route and the MAX phase Ti3SiC2 was selected for the application trials as it had been reported to show excellent corrosion resistance [1].
 
Material batches comprising calcined alumina, carbon, as well as Si and Ti sources were melted in an electric arc furnace and characterisation of the fused material showed that in addition to Ti3SiC2 phases, Al2O3, SiC, TiC, and Al28C6N6O21 were also present. Recipes of commercially available refractory bricks composed of alumina (~ 90 wt.%), graphite (~ 5 wt.%), and Si-containing raw materials were modified by replacing all the alumina with the fused Ti3SiC2 MAX phase containing material, which had been crushed to the appropriate grain sizes. After firing the bricks at 1500 °C in a reducing atmosphere, the influence of the MAX phase containing material on various refractory properties was investigated. 

[1] Xie, J., Wang, X., Li, A., Li, F. and Zhou, Y. (2012). Corrosion behavior of selected Mn+1AXn phases in hot concentrated HCl solution: Effect of A element and MX layer. Corrosion Science, 60, pp.129–135.