ANALYSIS OF ALUMINUM-OXIDE AND SILICON-CARBIDE CERAMIC MATERIALS BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The use of inductively coupled plasma mass spectrometry (ICP-MS) for trace element determinations in Al2O3 and SiC powders as well as in compact SiC ceramics, subsequent to grinding to a particle size of <20 mum, was investigated. The dissolution procedure, optimized for Al2O3, included treatment with HCl and H2SO4. For ICP-MS analyses the maximum tolerable Al2O3 content in the solutions to be measured was found to be 400 mug ml-1, for which detection limits in the range 0.002-2 mug g-1 were obtained. Analyses of real samples in the concentration range of 0.05 to several hundred mug g-1 will be discussed in terms of precision and accuracy and it will be shown that leaching of the powders with acids could provide information on the localization of the impurities. The influence of the removal of Cl from the analyte solutions on spectral interferences in the low mass range and of cooling the spray chamber on the power of detection will be discussed. A further method of improving the power of detection could lie in matrix removal, based on the on-line complexation of Co, Cu, Cr, Fe, Ga, Mn, Ni and V with hexamethylenedithiocarbamate. For SiC powders dissolution by treatment with HNO3, H2SO4 and HF will be shown to lead to a number of spectral interferences and to limit the tolerable analyte concentration to 500 mug ml-1, for which detection limits range from 0.002 (for heavy elements) to 10 mug g-1 for elements such as Mg. Results for the determination of B, Na, Al, V, Cr, Mn, Fe, Ni, Co, Cu, Ga, Sr, Y, Zr, In, Sn, Ba, La, Hf, Pb and U in ceramic powders of industrial importance will be presented.