The possibility of achieving very high compressive stresses at the surface of nepheline glass-ceramics, owing to the transformation of main crystal phase into kalsilite, was discovered more than 40 years ago, but the very long processing times associated to conventional glass-ceramic manufacturing prevented extensive applications. The present work aims, on one hand, to explore the feasibility of nepheline-containing glass-ceramics by rapid sintering of fine glass powders and, on the other hand, to renew interest on strengthening by ion exchange induced transformation. For a selected glass-ceramic, developed using glass cullet as main raw material and sintered at very low temperature (840 degrees C), ion exchange treatments were found to be effective especially in increasing the reliability of samples (e.g. Weibull's modulus exceeding 18).

Keywords: Fast sintering; X Ray Diffraction; Chemical tempering methods; Glass ceramics; Nepheline; Ion exchange; CRT Glass; Bending strength; Porous ceramics