นวัตกรรมการผลิตสโตนแวร์ชนิดเคลือบใสด้วยการเผาครั้ง เดียวสาหรับเครื่องใช้บนโต๊ะอาหาร

Abstract

The aims of this study were to study the effect of ball clay, bentonite white, pyrophyllite and particle size of stoneware body on RAM press formability and firing behavior, and to study the effect of alkali ratio, Al2O3:SiO2 ratio, nepheline syenite, particle size and density of clear glaze slip on the quality of the glaze-sprayed layer and melting ability. Stone ware body and clear glaze were single fired at 1280oC for 30 min with 5oC/min in a gas kiln in reduction atmosphere, and then were normal cooled to ambient temperature. The phase transformation and microstructure of bodies and glazes were evaluated. The technological properties were also investigated for table ware production. The results showed that the tableware production was successful with the single-fired technique. The vitrification and properties of single-fired samples were developed relating to the addition of 3 wt% pyrophyllite and 2 wt% bentonite. The stoneware body could be formed by RAM press. As a result of the XRD pattern, the major phases were mullite (3Al2O3.2SiO2) and free silica (SiO2). The properties of the product were shown that the linear shrinkage at 10.82%, water absorption at 0.17% and MOR at 153.21 MPa. The clear glaze could be sprayed on the dried products without defects. After single firing at 1280oC, the glaze was completely melted presenting clear layer without crazing. The melting of glaze had started before the stoneware body reached to complete vitrification. The properties of clear glaze were also developed with the addition of 3 wt% napheline syenite. The maximum vickers microhardness of the glazes was approximately at 948.10 HV and the maximum glossy at 71.5 GU. These properties are compatible with those of commercial tableware by single-fired technique.