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models: metallic cao-al2o3-sio2 eutectic

updated tue 3 jun 03


Louis Katz on mon 2 jun 03

This will probably go beyond the border into philosophy but so it goes.

Models are developed from data. They are our means of grasping order
from chaos or seeming chaos. Models most would say are necessarily
imperfect. I often refer to them as the lies we use to order reality.

The whole concept of fluxes, although useful is flawed.o say that
calcium fluxes the alumina and silica is as useful as saying the
alumina fluxes the silica and calcia. Since most any ingredient added
to another ingredient will disorder its structure and lower the melting
point, nearly everything is flux , primary or secondary.

It has been interesting to have the significance finally get through my
skull (thanks Ivor) of the differing amounts of energy needed to melt
mixtures of compounds than to melt the pure oxides themselves. But I
think the significance of this fact to glazes can be over stated. We do
not work with very pure materials. The idea that calcia could be a
significant glaze flux at cone 6 is a reasonable morsel to be gleaned
from a phase diagram. Only trying it will show whether it proves to be

I could certainly know more about the whole topic and hopefully I
will,,,some day. In the past years on clayart someone (maybe Ivor?) has
suggested that looking at the liquidous lines on phase diagrams would
be more usefull than only looking at the eutectics. The liquidous line
is the line on a diagram above which all the ingredients are liquid.
This is a truism, the liquidous line contains the eutectics and much
more information.

Sorry I ramble,


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