| 摘要 |
A porous ceramic body comprises a three-dimensional framework containing silica, all of which is in the form of a tectosilicate, alumina, and the equivalent of 8% Li2/O, 10% Na2/O, 6% K2/O, 3-4% BeO, 5-20% SrO, 8-32% BaO or a combination thereof, and up to 8% MgO or up to 32% CaO or a combination thereof, all by weight. It is preferred that the Al2/O3 and other metal oxide(s) in excess of that contributing to the tectosilicate are present as the mineral species corundum, periclase, or metal aluminates (including spinels). Species which have the tectosilicate structure include quartz, feldspars and the feldspathoids carnegi#qite, kaliophyllite, leucite, calcium gehlenite and strontium gehlenite. Suitable starting materials include clays, talc, feldspar, dolomite, flint alumina and carbonates; the green body may be shaped using a sodium silicate of a polyethylene resin binder and prefired at a temperature above the decomposition temperature of any carbonate present, i.e. generally above 1500 DEG F., but below 2000 DEG F. to provide a ceramic body of 60% (by volume) porosity. A fully fired body may be obtained therefrom by refiring at a temperature above 2000 DEG F., generally 2300 DEG F.-2700 DEG F. A composite member is produced from the porous ceramic body by filling the pores with liquid, viscous, or solid materials including thermoplastic resins, metals and alloys, or by merely coating the pores with, for example, resins or metals. missing page 284 |
