Chemical and phase characterisation of ceramic pigments

The present study was undertaken to extend a methodology established by the authors for characterising ceramic pigments. Ceramic pigments can be classified according to the American Dry Color Manufacturers' Association (DCMA) classification. The pigments used most frequently in the ceramic industry belong to five DCMA classes: Class III: Corundum-hematite, Class XI: Rutile-cassiterite, Class XII: Sphene, Class XIII: Spinel, and Class XIV: Zircon. Specific analytical methods have been established in this study to characterise the chemical composition and phases of types of pigments from these classes, using x-ray fluorescence (XRF) spectrometry for chemical characterisation and x-ray diffraction (XRD) for phase analysis. Sample preparation in the form of beads for the XRF measurement was optimised by determining the most appropriate sample/flux ratio for each type of pigment. Calibration and validation standards were prepared from mixtures of reference materials, as no pigment reference materials are available. The validation standards have then been used to validate the proposed methodology for the chemical and phase characterisation of a representative sample of ceramic pigments from the foregoing five DCMA classes. Copyright (C) 2007 John Wiley & Sons, Ltd.