The effect on chamotte clay properties of opacifying and matting oxides

Chamotte clay is generally used by the artists working for free shaping methods. It is particularly well suited for the production of large-size works. It has varying color tones depending on the ratio of iron oxide in the body composition at high temperatures. ZrO2, SnO2, ZnO and TiO2 are widely used oxides to obtain whiteness, opacity and matting in ceramic glaze, clay, and engobes. In this study ZrSiO4 as a resource ZrO2, SnO2, ZnO ve TiO2 were added in certain amounts into the chamotte clay in accordance with the dual system and clay mixture with plastic forming properties are prepared. The shrinkage, color and water absorbtion properties of these mixtures and moreover their appropriateness of usage as slip were analyzed. All clay bodies prepared and slips applied to the trial plates with pouring method were fired as both glazed and unglazed at 1160 0C. It was determined that zinc and titanium oxides led to obvious changes in colour of the chamotte clay at this temperature. In general, it was observed that colours of the bodies had a gradually lightening range from brick colour to yellowish cream and beige tones after firing. Keywords: Opacifying oxides, Matting oxides, Chamotte clay