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High‐Temperature Glazing of Alumina Bodies
Author(s) -
FISHER EUGENE,
TWELLS ROBERT
Publication year - 1957
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1957.tb12558.x
Subject(s) - glaze , glazing , potash , materials science , porosity , mineralogy , composite material , metallurgy , potassium , chemistry , ceramic
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 Al 2 O 3 , 15.0 SiO 2 and 1.0 RO, 1.75 Al 2 O 3 , 15.0 SiO 2 for one‐fire and two‐fire glazing, respectively.