Effect of talc addition on the sintering of traditional triaxial ceramics compositions

Reference	Presenter	Authors (Institution)	Abstract
16-017	EDUARDO QUINTEIRO	QUINTEIRO, E.(Universidade Federal de São Paulo); Cabrelon, M.D.(Universidade Federal de São Paulo); Araújo, I.N.(Universidade Federal de São Paulo);	Feldspars are the most abundant mineral group in the earth's crust. These are Na, Ca, K and Ba aluminosilicates. The feldspars most commonly used as raw materials in the traditional ceramics industry are sodium feldspars (NaAlSi3O8) and potassium feldspars (KAlSi3O8). Its main function in formulations is to act as a flux during the sintering process, promoting the development of a dense microstructure due to the formation of liquid phases that help reduce the porosity and promote the densification of the ceramic products. Mineralogically the talc is a phyllosilicate having the theoretical formula Si4O10Mg3(OH)2. Formulations containing talc additions, partially replacing feldspars, have demonstrated in industrial practice a decrease in the sintering temperature due to the formation of eutectic liquid. The aim of this study was to formulate mixtures in order to optimize the composition, quantity and viscosity of the liquid phase formed during typical sintering treatments of traditional products, based on the binary diagrams potassium feldspar-talc and sodium feldspar-talc. The characterizations performed included: (1) raw materials: chemical and mineralogical identification; (2) formulations processing characteristics: gresification diagrams, melting cones and pyroplastic deformation; (3) finished products: determination of the proportion and composition of the resulting vitreous phase. The results showed that the addition of the talc provided a greater stability of the sintering behavior of the formulations, resulting in a reduction of the maximum sintering temperature.
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