NMR TECHNIQUES: A NON-DESTRUCTIVE ANALYSIS TO FOLLOW MICROSTRUCTURAL CHANGES INDUCED IN CERAMICS MICROSTRUCTURAL CHANGES INDUCED IN CERAMICS

Tiles were produced from a standard porcelain stoneware body comprising 45% clay, 31% feldspar and 26% silica sand, and also from a body in which 5% of soda feldspar was replaced by crushed soda-lime glass (coarse or fine). The tiles were fired to 1140 or 1160 C and characterised by microstructural studies, and measurements of pore size distribution (mercury intrusion), porosity and water absorption. Water-saturated tiles were also studied using magnetic resonance relaxation and magnetic resonance imaging of the water 1H nuclei. Porosity and pore size distributions determined from the NMR studies were in good agreement with the values obtained using the traditional techniques. Larger pores connected by smaller channels were formed on increasing the firing temperature from 1140 to 1160 C. The introduction of fine crushed glass enhanced the sinterability of the body, but made it more sensitive to firing temperature. 9 refs.