Application of Thermochemistry and X-ray Semi-Quantitative Phase Analysis in Forsterite Powder Synthesis by Solid State Reaction of Magnesium Oxide and Mg-Chlorite

ABSTRACT

In this paper, high purity forsterite powder with anorthite grain boundary has been synthesized by solid state reaction of industrial grade magnesium oxide and Mg-chlorite at 1100°C. ASTM C547 and X-ray powder diffraction (XRD) were used for chemical and phase analysis of raw materials. For microstructural analysis of prepared specimens, XRD and back scatter scanning electron microscopy (BS-SEM) were used. BS-SEM and elements mapping show the distribution of Mg, Si and O elements in grains, and point analysis of these elements shows the portion of atomic percent as forsterite. The detected elements in grain boundary are Si, Al, Ca and O; and based on XRD pattern of the specimens, the anorthite phase is detected. MAUD software was used for semi-quantitative analysis of phases based on Rietveld method in TC specimen, the amounts of detected phases are 15.6 wt% free periclase and 84.4 wt% forsterite that are very close to calculated amounts for 12.89 wt% free periclase and 87.11 wt% forsterite. The amount of forming phases strongly depends on well mixing, soaking time and temperature, and reactivity of raw materials.

GRAPHICAL ABSTRACT

Keywords:

• X-ray powder diffraction
• Semi-quantitative phase analysis
• Solid state reaction
• Back scatter scanning electron microscopy
• Rietveld method