KJ Ceramics 31

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Detailed Program

Paper Number : GL-P03

Time Frame : 12:00~13:30

Presentation Date : Thursday, 27, November

Session Name : Glass & Opto-Electronic Materials

Session Chair 1# : -

Session Chair 2# : -

The contributions of flaw healing effect and ion-exchange to the strength improvement of glass-infiltrated alumina

Mr. Dong Hwan Kim

KOREA INSTITUTE OF CERAMIC ENGINEERING & TECHNOLOGY

It is well-known that the classic ceramics, as porcelain, are strengthened with thermal expansion mismatch between body and glaze and reduction of the defects on body using glaze coating. Several researchers shows that a low thermal expansion glass penetrated into the surface of dense alumina and zirconia ceramics produced a compressive stress at surface due to the thermal expansion mismatch on cooling thereby strengthening the ceramics remarkably[1,2]. However, it is little-known how much is the difference between the contribution of the flaw healing and thermal expansion mismatching for strengthening the ceramics. In order to exclude thermal expansion mismatching and only contribute the defect healing effect, we selected the glasses with thermal expansion coefficient similar to ceramic body for infiltration. Meanwhile, it was checked whether the ion exchange method could work to strengthen its glass-infiltrated ceramics or not. High-density alumina and porous alumina were penetrated by Na2O-Al2O3-SiO2 and Na2O-CaO-SiO2 system glasses, which respectively have similar or larger coefficients of thermal expansion than alumina. Flexural strength of high-density alumina was improved by up to 24 % due to only flaw healing of glass-infiltration without compressive stress generation caused by the difference in the coefficient of thermal expansion. The combination of glass-infiltration and an ion-exchange process enhanced the mechanical properties of the alumina/glass composite by more than 60 %.

Acknowledgements :

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