DEVELOPMENT OF LOW THERMAL EXPANSION GLAZE CORDIERITE BODY
Keywords:
Cordierite, cookware, low expansion, glazeAbstract
A cordierite body with a low thermal expansion coefficient of 1.5-4 – 10-6/oC has excellent thermal shock resistance and can be used for manufacturing stove-top ceramic cookware. This study is aimed at developing a glaze for a cordierite body having a thermal expansion coefficient less than 3.09 × 10-6/oC. The glazes in a Li2O-KNaO-CaO-MgO-Al2O3-SiO2 system were calculated and prepared. The selected raw materials were mixed and ground in a ball mill. The samples were dip coated onto the cordierite body and fired at 1300oC with 2 h soaking time. After firing, the goodvisual crack-free samples were tested for crazing resistance by autoclave at 250 psi. The phases and thermal expansion coefficient were also analyzed by XRD and a dilatometer. The selected sample was applied to 7 inch diameter cordierite pots and these were tested for cooking on a gas stove-top or hot plate for more than 50 cycles. The results show that the glaze composed of virgilite and a zircon phase had a thermal expansion coefficient of 2.61 × 10-6/oC, and was smooth and crack-free.
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