|Monthly Tech-Tip |
The term is generally used in a generic sense to refer to porcelain tableware that has an extremely low thermal expansion. While "Corning ware", for example, is a trade secret of the Corning Glass, it is well known that oven-to-table ware is produced by controlling the firing curve to achieve the development of the beta spodumene phase in the porcelain microstructure. 'Pyrex' ware is a low expansion high silica borosilicate glass. The bodies are, of course, based on spodumene.
If you want to produce this type of body then you have some serious R&D to do to develop a recipe and a firing procedure!
Spodumene is a lithium sourcing feldspar, an alternative to lithium carbonate to supply Li2O to ceramic glazes. Contains up to about 8% Li2O.
Co-efficient of Thermal Expansion
Ceramics are brittle and many types will crack if subjected to sudden heating or cooling. Some do not. Why? Differences in their co-efficients of thermal expansion.
Low Expansion Material
Materials used to make bodies requiring low expansion (e.g. flameware, refractories). The individual particles of these materials have low expansion. Some of theme even expand at certain temperature ranges.
|By Tony Hansen|
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