The Unity Molecular Formula Approach to Glaze Development

Abstract

The study of glazes is inhibited by the complex nature of multiple oxide compositions typically witnessed in industrial and art glazes. This research systematically addresses this complexity issue in multiple glaze compositions consisting of SiO2, Al2O3, CaO, MgO, Li2O, K2O, and Na2O oxides through the use of the Unity Molecular Formula (UMF) approach. The UMF limits for simple glaze compositions are defined for matte and gloss surface development. These limits are defined using Glossmeter, SEM/EDS, XRD, ICP-AES, and Optical Interferometry analytical techniques. Included is the correlation of gloss and surface roughness characterization techniques, which is compared with visual observations in order to define the most accurate surface quantification tool. Also a proposed technique that will define the glass formation boundary is introduced by using the internal standard method of quantitative XRD coupled with ICP-AES. Results show that matte formation, in the glaze systems tested, is either a result of underfiring or devitrification. Also, the proposed glass formation boundary technique has the ability to accurately define the glass formation boundary, but it may only be restricted to use with simple, three component glass compositions. Crystalline phases exhibiting solid solution, found in more complex glaze systems, reduce the accuracy of the technique. Finally, it is demonstrated that the optical interferometer is superior to gloss measurement when quantifying a wide range of glaze surface qualities. Through this approach multi-component glaze systems can be thoroughly analyzed and accurately represented in terms of its development using the UMF approach. The analytical techniques incorporated in this study effectively evaluate the complex glaze systems allowing for further study into more complex systems.