Near-Net-Shape Forming of Celsian Ceramics from Ion-Exchanged Zeolite Precursors

A technique has been developed for the synthesis and near-net-shape forming of celsian glass-ceramics. This technique involves ion exchange of zeolite precursor powders, heat treatment of the powders to temperatures between 800–90°C to form a glassy phase during which the samples are formed under low stresses (<20 MPa). Upon further heat treatment to about 1000°C, crystallization occurs and the amorphous formed body is transformed to the celsian ceramic phase. Using this technique, and through the addition of monoclinic seed particles as well as a mineralizer, monoclinic celsian was produced at temperatures as low as 1000°C at heat treatment times of less than one hour. This forming technique also resulted in a significant reduction in the porosity of the ceramic bodies compared to free-sintered samples.