Quantitative Analysis of Sphene (CaTiOSiO4) and Wollastonite (CaSiO3) Crystallizations in Annealed Ceramic Frits by FT-IR Absorption Spectroscopy

Abstract

Results of this study have shown the feasibility of FT-IR absorption spectra (between 500 and 700 cm−1) for the quantitative determination of the nucleation and crystal growths of sphene (CaTiOSiO4) and wollastonite (β-CaSiO3) in two separate typical ceramic frits that have been annealed between 800 and 1000°C. Synthetic sphene ceramics and natural wollastonite, both of high purity and excellent crystallinity, serve as standard materials for calibration by the classical least-squares method (Basic Quant), employing the peaks of a sharp band at 561–566 cm−1 assigned to the SiO4 vibration and that of a shoulder (676 cm−1) of a broad band assigned to TiO6 vibrations. The correlation coefficients for these calibrations (absorbance vs. concentration of crystalline phase) are given as 0.9964, 0.9936, and 0.9937, respectively. Between annealing temperatures of 850 and 1000°C, both sphene and wollastonite phases appear to grow steadily in frit-S and frit-W, when the highest value of crystal growth is noted for specimens annealed at 1000°C, being approximately 80 wt % and 66 wt % of the formulated content, respectively. Scanning electron micrographs provide pictorial evidence to show that quantitative characterization of crystalline phase growth in ceramic frits by FT-IR absorption spectra is an appropriate technique.