Microstructures and Properties of Low Cement High Alumina Based Refractory Castable: Effect of Y2O3 Content

Abstract

High alumina castables show excellent features at high temperatures, such as high thermal stability, high hot strength, resistance to slag and metal corrosion, low coefficient of thermal expansion, good chemical stability, remarkable refractoriness, excellent thermal shock and abrasion resistance, etc.[1-2]. The effect of yttria addition up to 2 wt.% on low cement high alumina castable was studied. Castable compositions with self-flowing and vibratable consistency (distribution coefficients, q = 0.21 and 0.29) were prepared using commercial raw materials and processed as per the conventional processing route, cured at 110°C, and fired at 1000 and 1550 °C. 2 wt.% (Y2O3) addition on the cement-bonded high alumina castable increased the bulk density, decreased the porosity and increased the cold crushing strenth value at 1550 °C with q=0.21. XRD analysis [Fig.1 (A)] confirms the formation of the yttrium aluminate phase (YAM, Y4Al2O9). Microstructural and EDX analysis (Fig.1 (B) and C) showed a well compact inter-locking structure is formed with 2 wt.% yttria addition at 1550oC [3] .