| abstract |
The present invention is a glass-ceramic material and method of making useful for joining a solid ceramic component and at least one other solid component. The material is a blend of M1-M2-M3-M4, wherein M1 is BaO, SrO, CaO, MgO, or combinations thereof, M2 is Al2O3, present in the blend in an amount from 2 to 15 mol%, M3 is SiO2 with up to 50 mol% B203 and a metal oxide selected from the group of La2O3, Y2O3, Nd2O3 or combinations thereof, or between 0.1 and 7.5 mol% K2O. In the case of a metal oxide from the group La2O3, Y2O3, Nd2O3 or combinations thereof, it is preferred that the composition contain an additional 0.1 to 3 mol %CuO. In all cases, the glass ceramic material in a crystalline phase substantially matches a coefficient of thermal expansion of solid electrolytes having a thermal expansion coefficient of 12 x 10-6 °C-1 as measured from 25 °C to 1000 °C, and does not degrade with repeated heat cycling. According to the present invention, the series of glass ceramics in the M1-Al2O3-M3-M4 system can be used to join or seal both tubular and planar solid oxide fuel cells, oxygen electrolyzers, and membrane reactors for the production of syngas, commodity chemicals and other products. |