| 摘要 |
1429412 Porous part comprisingα-alumina COMPAGNIE GENERALE D'ELECTRICITE 5 March 1974 [7 March 1973] 9929/74 Heading C1A A porous member of crystallineα-alumina which comprises a plurality of ducts extending from one face of the member to the other wherein the diameter of at least a part of each duct is less than one hundredth of a micron is produced by heating a member formed of a crystalline #-aluminate based on from 5 to 11 moles of alumina per mole of metal oxide, e.g. 8À5 Al 2 O 3 .Na 2 O or 5À3 Al 2 O 3 .Na 2 O or an admixture thereof, at a temperature higher than the sublimation temperature of the metal oxide but lower than the melting temperature of the #- aluminate so as to sublime the metallic oxide from the #-aluminate and to convert the aluminate toα-alumina. The metal oxide may also be that of potassium, rubidium, cesium, thallium or silver. |
