|Monthly Tech-Tip |
During firing of traditional porcelains, kaolin particles convert to long mullite crystals around 1000C. This transformation is a significant reason why vitrified porcelain is so strong. A porcelain in which the transformation has occurred becomes more than just a bunch of silica particles glued together in a feldspar-silicate glass, the mullite creates a fibrous mesh that greatly strengthens the matrix.
Ceramics, by their brittle nature, have high compressive strength. But in functional ceramics we are more concerned about the tensile strength as this relates better to serviceability.
|Temperatures||Metakaolin converts to mullite (1050-)|
|By Tony Hansen|
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