QUANTITATIVE PHASE COMPOSITIONS ANALYSIS OF -SPODUMENE (Li2O.Al2O3.4SiO2) MODIFIED Al2O3-CaAl12O19 COMPOSITES

The analysis of x-ray diffraction (XRD) patterns by the Rietveld method was tested to the quantitatively phase compositions of b-spodumene (Li 2 O.Al 2 O 3 .4SiO 2 ) modified Al 2 O 3 -CaAl 12 O 19 composites. It is clear that the addition of Li 2 O.Al 2 O 3 .4SiO 2 has significant effect on the phase composition of the Al 2 O 3 -CaAl 12 O 19 composites as confirmed by XRD Rietveld refinement analysis. The addition of > 2.5 wt % b--spodumene caused the reduction of CaAl 12 O 19 content and the formation of -quartz solid solution, which can be attributed due to the in-situ reaction sintering of alumina and Al 2 O 3 -CaAl 12 O 19 precursor to form b-spodumene modified Al 2 O 3 -CaAl 12 O 19 composite as expected was not achieved. The refinement x-ray diffraction data analysis showed that the goodness of fit (GOF) values was relatively low and the fluctuations in the difference plots showed a reasonable fit between the observed and the calculated plot. Keywords: Rietveld method, Al 2 O 3 -CaAl 12 O 19 composites, Li 2 O.Al 2 O 3 .4SiO 2 ( b -spodumene), reaction sintering