Transferred arc plasma processing of mullite-zirconia composite from natural bauxite and zircon sand

Low cost mullite-zirconia composites were prepared from the mixtures of natural bauxite and zircon sand by using transferred arc plasma processing. In this paper, a mixture of natural bauxite and zircon in the ratio of 7:3 by weight (based on composition of 3:2 mullite) was ball milled for 4 h and melted in the transferred arc plasma for 2 and 4 min. Argon was used as plasma forming gas. The torch was operated at 5 kW input power. The phase and microstructure formation of melted samples were investigated by XRD and SEM images. The results show that the processing time is a key factor to get a single phase mullite-zirconia composites with required microstructure.