A Study of the Chemistry of some Transition Metal Ions in Ceramic Glazes

Abstract

The general introduction gives a brief history of the development of ceramic articles from early Egyptian times to the present day, outlining the importance of the independent development of Chinese ceramics as well as the recent development of the British pottery industry. The value of a number of spectroscopic techniques in investigating the chemistry of transition metal ions in ceramic glazes is evaluated. Chapter three outlines the room temperature and liquid nitrogen temperature Mossbauer and magnetochemistry results for a number of Iron (III) dipyridyl complexes in order to evaluate the use of Mossbauer spectroscopy in the investigation of iron in weak ligand fields similar to those encountered in a glaze environment. Chapter four describes the Mossbauer X-ray Diffraction and Electron Spin Resonance results for a number of iron containing glazes. Iron is introduced in various forms and firings are performed under oxidizing and inert conditions. The Mossbauer results indicate that the final environment of iron in the fully matured glaze depends upon the method of introduction. Comparison of the Mossbauer parameters for a number of Chinese ceramic glaze samples also serves to illustrate this point. ESR of Copper containing glazes are also reported. Copper (II) is found to exist in a highly distorted octahedral environment. Visible spectra of Chromium containing glazes are also reported and compared with some highly acidic chromium (III) solution spectra in order to gain a quantitative estimate of the sort of ligand field strengths normally encountered in a glaze environment. Replacement of Strontium for Calcium in Iron, Copper and Chromium containing glazes in no way alters the environment of the transition metal ions.