Abstract

Zircon stains for the ceramics industry have been produced commercially since 1949. At present the commercial stains are mainly zircon (ZrO₂.SiO₂) doped with vanadium, praseodymium or iron to produce blue, yellow or pink colours respectively. A research programme is in progress to study the factors controlling the colours of these zircon-based glaze stains and photo-acoustic spectroscopy has been used to monitor the colours of stains prepared by different routes. Spectra of coral pink tiles reveal a broad absorption between 600 nm and 350 nm which is yet to be identified. A blue glaze has a spectrum which suggests the presence of V⁴⁺ but the yellow glaze has a sharp cut-off near 470 nm which is quite uncharacteristic of the spectrum expected from Pr³⁺. Single crystal specimens of the doped zircon are being prepared and these too will be examined photo-acoustically. An attempt will also be made to obtain transmission measurements.

© 1981 Optical Society of America