| abstract |
The invention is directed to highly crystalline, frit-sintered glass-ceramic compositions having a coefficient of thermal expansion in the range of 85-115x10-7 DEG C. The primary crystal phases of the glass-ceramics of the invention possess a cyclosilicate structure. The glass-ceramic of the invention are useful as metal-to-metal, metal-to-ceramic and ceramic-to-ceramic sealing agents, and also as high-performance coating for metals and ceramics. In their broadest composition the glass-ceramic contain, in weight percent, 30-55% SiO2, 5-40% CaO, 0-50% BaO, 0.1-10% Al2O3, and 0-40% SrO, wherein the sum of CaO+BaO+SrO is in the range of 35-65 wt.%. Optionally, the glass-ceramic compositions may contain at least one from the group of > 0-15 wt.% MgO and > 0-10 wt.% ZnO. Also optionally, the glass ceramic compositions may contain > 0-10 wt.% of at least one transition metal or rare earth metal oxide. |