Glass ceramics

The literature on ceramic-like glassy cryst. products from glass is reviewed. The crystal phase of Pyroceram 9609 is cordierite (2MgO.2Al2O3.-5SiO2), with TiO2 as a seed-forming addn.: tan d = 3 * 10-4 at 100 Deg for a frequency of 24 * 1010 cycles. With Pyroceram 9608, TiO2 is also used for the seed formation, and the main crystal phases are: b-spodumene (Li2O.Al2O3.4SiO2) or b-eucryptite (Li2O.Al2O3.2SiO2), or a mixt. of the 2; the thermal expansion was 0 in the range -75 Deg to +60 Deg and 11 * 10-7/ DegK. in the range 0-500 Deg. A new method is described for increasing the mech. strength of glass. [on SciFinder (R)