Characterization of Mullite-Zirconia Composite Processed byNon-Transferred and Transferred Arc Plasma

The arc plasma melting technique is a simple method to synthesize high temperaturereaction composites. In this study, mullite-zirconia composite was synthesized by transferred andnon-transferred arc plasma melting, and the results were compared. A mixture of alumina andzircon powders with a mole ratio of 3 : 2 were ball milled for four hours and melted for two minutesin the transferred and non-transferred mode of plasma arcs. Argon and air were used as plasmaforming gases. The phase and microstructural formation of melted samples were investigated byX-ray diffraction (XRD) and scanning electron microscope (SEM). The microstructure of the compositeswas found to be affected by the mode of melting. In transferred arc melting, zirconia flowerswith uniform lines along with mullite whiskers were obtained. In the case of non-transferred arcplasma melting, mullite whiskers along with star shape zirconia were formed. Differential thermalanalysis (DTA) of the synthesized mullite-zirconia composites provided a deeper understanding ofthe mechanisms of mullite formation during the two different processes.