Ceramics-Silikáty 51 (2) 102-105 (2007)

YOUNG'S MODULUS OF PORCELAIN MIXTURE AFTER FIRING IN THE DEHYDROXYLATION REGION

I. Štubňa, A. Trník

Samples were prepared from a raw material mixture containing 50 % of kaolin, 25 % of quartz, and 25 % of feldspar and extruded from the plastic paste. Young's modulus was measured by the resonant method using flexural vibrations. The results of Young's modulus measurement at the rooms temperature, obtained from the samples fired at a temperature in the range 420-740°C, show that it is necessary to consider the increase of the porosity during dehydroxylation as the most important cause of the decrease of the values of Young's modulus. The role of the b « a reversible transformation of quartz grains inside the ceramic material as well as the role of the solid state sintering in the considered temperature interval turns out to be negligible.

Keywords: Dehydroxylation, Young's modulus, Porosity.