Effect of microstructure on mechanical properties of porcelain stoneware

This work examines the effect of microstructure (aspect ratio of mullite crystals and proportion of crystalline and amorphous phases) as well as different physical features (bulk density, closed and open porosity and absolute density) on the mechanical properties of a standard porcelain stoneware composition (50% kaolinitic clay, 40% feldspar and 10% quartz) fired in the 1200–1300 °C temperature interval using a fast firing schedule. The mechanical behaviour was evaluated in terms of bending strength, Vickers microhardness, fracture toughness and Young's modulus. After viewing the results, it can be concluded that increased σf, Hv and E values were mainly due to open porosity, percentage of mullite phase and morphology of secondary mullite needles, whereas closed porosity and quartz particles have no influence on these properties.This research was supported by the Spanish Science and Technology Ministry (Projects MAT2000-1422 and MAT2003-2915). The authors gratefully acknowledge Compañía Europea de Arcillas, S.A. for providing raw materials. The authors thank IRICA from University of Castilla-La Mancha (Spain) for experimental assistance.Peer reviewe