การทดลองเนื้อดินสำหรับดินสอเขียนสีใต้เคลือบ

Abstract

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Clay Body for Underglaze Ceramic Pencils

The purpose of this research was to find clay bodies suitable for making underglaze ceramic pencils. Maetarn ball clay, potash feldspar, silica, bentonite, and ceramic underglaze stain were used as raw materials. The ratios of Maetam ball clay, potash feldspar, and silica were calculated using the triangular method. The proportions were 50-80% clay, 10-40% potash feldspar, and 10-40% silica. All 10 mixing ratios were added with 5 percent bentonite and black ceramic stain and extruded into round bars, fired to 800 degree Celsius and tested for their physical properties and usages.

The results of the research showed that none of the 10 tested clay bodies exhibited any apparent differences in their properties in terms of plasticity for ease of forming, hardness, adhesion to the surface of the wares after decoration and glazing, and the intensity of the color after being fired. However, tests of their physical properties found that clay body number 3 (60 percent Maetarn ball clay, 30 percent potash feldspar, 10 percent silica, with 5 percent bentonite and 15 percent ceramic underglaze stain added) exhibited the highest bending strength at 167.881 kilogram per square centimeter, which would aid the durability of the pencils during use and storage. This was therefore chosen as the most suitable clay body for underglaze pencils.