Chemical Composition of Clays for Pottery in Malaysia: A Review

Abstract

Pottery in Malaysia is been known for its utilized functions and unique properties. Clays as the pottery’s raw materials are a major factor that affecting the quality and reliability of some pottery products. Observations on clays’ elements and phases are very helpful for productions of the good pottery. Hence, in this review, chemical compositions of clays in terms of elements and phases structures are discussed. Basically, the most elements found in clays are Si, Al, Fe, Ti, K and Ca. Depends on location, the concentrations for those clays elements in Malaysia are at range of 24.8 – 32.4 for Si, 10.8 – 19.0 for Al, 0.09 – 2.12 for Fe, 0.08 – 1.13 for Ti and 0.45 – 3.39 for K. Several studies reported, they exist in form of oxide compound which are SiO₂, Al₂O₃, Fe₂O₃, TiO₂, MgO, CaO, Na₂O, K₂O and P₂O₅. The percentages of elements in clays do not only determine the clays characteristics, but also influence the physical, mechanical and chemical properties of the end product. Increase of major element like silica arises the melting point, lowers the fluidity, and enhances the hardness and tensile strength. Meanwhile, increase alumina content enables the green body to withstand the sintering temperature and also increase the hardness of the pottery.