Method for the manufacture of dense-sintered glass ceramic moldings

摘要

A method for the manufacture of dense-sintered glass-ceramic shaped objects which have a coefficient of thermal expansion, alpha , of -0.5x10-6/K to 1.8x10-6/K in the range between 20 DEG C. and 700 DEG C. whereby ceramizable glass powder and/or glass-ceramic powder from the system Li2O-Al2O3-SiO2 is slip-cast by means of porous molds, dried, pretempered if necessary at temperatures up to 600 DEG C., vitrified and then sintered until the sintering temperature is reached up to relative densities of greater than 0.96 and ceramized, and whereby the glass powder and/or the glass ceramic-powder is prepared in a first grain size fraction of less than 63 mu m, in particular less than 45 mu m, and in a second grain size fraction of less than 7 mu m, in a ratio of the fractions to one another between 2:1 and 4:1, to form a stable, pourable slurry. The method can be used for the manufacture of industrial ceramics, but also for the manufacture of complex-shaped, large-volume and thin-walled hollow containers, in particular for use as cooking utensils which are resistant to thermal shock, as well as for dinnerware, solid ceramic castings and composites.