I.Lewis on thu 30 dec 99
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Paul Taylor wrote on Tue, Dec 28, 1999, 5:17 pm
At what temperatures do mulite(sic) and other silicate crystals or
aluminosilicate crystals- et all- form and their sizes relative to the
temperature?
Paul Taylor asks an interesting question. I think he should consult a copy =
of
Equilibrium Phase Diagrams for Ceramists put out by the American Ceramic
Society. From information about the main Ternary Systems he would be able to
infer the liquidus points (Point to which a recipe mixture would need to be
heated to ensure total solution of all components) occur and predict =
minerals
which would crystallise from any particular recipe.
However, the question which is asked is about Phase Transformation which is =
a
dynamic event not not about Phase Equilibrium systems. To the best of my
knowledge Phase Transformation Diagrams, which introduce the factor of Time,=
are
not available for ceramic systems.
Apart form exercising control over such glazes as the Zinc crystallises and =
some
of the copper transmutation glazes, most potters seem content to pull the =
plug
and let nature take it=92s own course once the cones have set. I am =
preparing a
speculative essay which looks at the concept of Phase Transformation of =
glazes.
Do the Glaze Gurus have any information in this direction?
Ivor Lewis.
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