CaO–MgO–SiO2 glass ceramics: Transferred arc plasma (TAP) synthesis and microstructural characterization

In this paper, synthesis of CaO–MgO–SiO2 glass ceramic using transferred arc plasma (TAP) processingmethod is illustrated. Homogeneous mixture of 51.6% SiO2, 35.6% CaO and 12.8% MgO prepared by drymixing in a ball mill was kept in the anode well (which is the melting bed) of the 10 kW transferredarc plasma torch. It was melted in plasma at an operating power of 5 kW (by varying the processing timefor 3, 5 and 8 min). The melt was cooled to solidify by applying forced air on it. The resulting sampleswere characterized for microstructure and phase composition. The phases were identified by scanningelectron microscopy (SEM), using the back-scattered electron (BSE) image mode and X-ray diffraction(XRD) and energy dispersive X-ray analysis (EDX). The microstructure was examined using opticalmicroscopy (OM) and scanning electron microscopy. The micro-hardness, density and porosity measurementsfor the synthesized samples were carried out. Differential thermal analysis (DTA) was performedto study the thermal evolution. The results show the formation of diopside phase in the transferred arcplasma melted CaO–MgO–SiO2 glass ceramic system achieved with in a quite considerable short time ofplasma processing. The method indicated that TAP technique could be a promising, time saving and onestepmanufacturing process for the production of functional bulk glass ceramics.