DETERMINATION OF SILICON DIOXIDE COATED ON ALUMINUM-OXIDE POWDER BY DIFFUSE REFLECTANCE INFRARED FOURIER-TRANSFORM SPECTROMETRY

Diffuse reflectance infrared Fourier transform (DRIFT) spectrometry was applied to the determination of silicon dioxide (SiO2) coated on aluminium oxide (Ai2O3) powders. Each sample was diluted with KBr powder to 1 wt%, after which the DRIFT spectrum was measured. The SiO2 peaks observed in the 1200 approximately 1000 cm-1 region and did not overlap with those of Al2O3 in the 900 approximately 550 cm-1 region. The peak height at 1090 cm-1 was measured and compared with the concentration of SiO2. A linear relationship was obtained between the peak height and SiO2 concentration in the range of 0 approximately 15 wt% SiO2. The slope of the line agreed well with that of the line for pure SiO2 fine powder in the same concentration range. The concentration of SiO2 coated on Al2O3 powder was determined by using the calibration line for pure SiO2 fine powder. The analytical results agreed well with the values obtained by ICP-AES.