Firing of Porcelain
Date
2014-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.
Abstract
It is common to think of fast firing of porcelain tiles as unrelated to the
conventional firing cycles typically used in the whitewares industry. In other
words, it appears that the densification and mineralogy in fast firing appear to
be inconsistent with conventional firing. It is also common to evaluate the
progress in firing behavior from the perspective of mullite formation, quartz
dissolution, and the densification kinetics. This study proposes that mullite
formation, quartz dissolution, and densification across all firing conditions are
completely consistent from fast firing to conventional firing. The data indicates
that mullite formation is completed early and is limited by the solubility of
alumina in the glass phase. The amount of mullite appears to be independent
of temperature, dwell time, and heating rate above 1200°C but mullite crystallite
size increases as a function of temperature, dwell time, with a small
dependence on heating rate. The undissolved quartz level—a direct result of
quartz dissolution—decreases linearly on a log-time scale. Similar to mullite
formation, quartz dissolution is independent of heating rate. It was also
confirmed that quartz dissolution is independent of the quartz particle size.
Moreover, this work proposes that mullite formation and quartz dissolution are
“diffusion limited processes.” In contrast, densification is dependent on
temperature, time, and heating rate dependent, presumably due to the
mechanics of viscous phase sintering. The results indicate that the minimum
amount of glass necessary to achieve full bulk density is about 53.3 weight
percent (±0.9%). True density, however, appears to be dependent on
temperature and dwell time, but is independent of heating rate, consistent with
the measured quartz dissolution behavior.
Description
Advisory committee members: Matthew Hall, Dawei Liu. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Ceramic Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis