Quantitative XRD Analysis of Hydrothermally-derived Leucite Content in Dental Porcelain Ceramics

In this study, the leucite contents in the sintered porcelain and hydrothermally-derived powders were determined by the quantitative XRD analysis using internal standard. The leucite powders were prepared at 800°C-1200°C. The dental porcelain was sintered at 850°C from the mixture of 20 mass% leucite prepared at 1100°C and 80 mass% low temperature frit. The four standards for quantitative XRD analysis were established by mixing the low temperature frit (as a balance material), the copper (as an internal standard) and different weight content of pure leucite synthesized by molten method. They were X-rayed over the 2θ ranges from 14.5° to 17.5°, 26.5° to 28.5° and 42.5° to 44.5° for measuring the integrated area of leucite (211), (400) peaks and copper (111) peak. The area of leucite (211) and (400) peaks was divided by the area of copper (111) peak respectively and two calibration curves were plotted from these data. Before measuring the leucite content in the synthetic leucite, 40 mass% synthetic leucite was mixed with 60 mass% frit, whereas the leucite content in the sintered porcelain was determined by the method directly. The result of quantitative XRD analysis showed that the leucite content in the synthesized powders and dental porcelain correlated very well with the treating temperature and image analysis of SEM picture. The standards set in the study may be useful for measuring the leucite content in other systems.