1. High-Temperature Glazing of Alumina Bodies
- Author
-
Eugene Fisher and Robert Twells
- Subjects
Chemical activity ,Glazing ,Materials science ,Glaze ,Materials Chemistry ,Ceramics and Composites ,High capacity ,Absorption (chemistry) ,Composite material ,Alkali metal ,Porosity ,Thermal expansion - Abstract
The chief problems in glazing alumina bodies at high temperatures are (1) high porosity of the body with high capacity for absorption at the glaze-fusion temperature, (2) difference in thermal expansion between body and glaze, and (3) chemical activity of body and glaze materials. It is preferable to use feldspathic glazes with the RO group composed of alkalis from high-potash feldspars augmented if necessary by small amounts of potash frits. The effects of varying alumina and silica, with the RO group composed entirely of alkali, are illustrated for a typical glaze field. The glazes were applied to four alumina bodies containing 0 to 30% clay. The specimens were fired to cone 18, one-fire and two-fire. The results show that the area of best glazes was centered around 1.0 RO, 1.5 Al2O3, 15.0 SiO2 and 1.0 RO, 1.75 Al2O3, 15.0 SiO2 for one-fire and two-fire glazing, respectively.
- Published
- 1957