A method for evaluation of the component uniformity of a powder mixture bymicro Fourier transform infrared spectrometry

A method for evaluating the uniformity of a small volume of components of f our kinds of zirconia and silica powder mixture in the range of 10(-3) to 1 0(-5) mm(3) was investigated using micro-Fourier transform infrared (micro- FTIR) reflectance spectrometry. Reflectance spectra (spot size 250 x 250 mu m(2)) were taken from 10 different locations within a sample and the relati ve standard deviation (RSD) of the peak height ratio (1100 cm(-1): assign t o Si-O vibration/600 cm(-1): assign to Zr-O vibration) was calculated for e ach sample. If the RSD value was below the error that accompanied the measu ring method (about 3%), the sample was regarded as uniform. The above opera tion was repeated with diminishing spot size (80 x 80 and 25 x 25 mum(2)) f or each sample, and the relationship between the RSD values and measuring v olume, which was estimated from spot size, was obtained. The least volumes (regarded as uniform) were obtained for each sample.