| 摘要 |
1,202,032. Transparent polycrystalline ceramics; modified rare earth oxides. GENERAL ELECTRIC CO. 11 Sept., 1967 [28 Sept., 1966], No. 41431/67. Headings C1A and C1J. A transparent polycrystallinic cubic ceramic consists of 2-15 mol. per cent of one or more ThO 2 , ZrO 2 and HfO 2 , the balance being (a) an oxide of an element of Ar. No. 66-71; or (b) a mixture of oxides of an element of Ar. No. 58-60, 62-71; or (c) a mixture of an oxide of an element of (b) with Y 2 O 3 , the oxides of (b) and (c) being proportioned that (1) their average cationic radii are no greater than 0À93 Šand (2) the differences in their cationic radii is no greater than 0.22 A. The mixture is fired at at least 1900‹ C. and if any oxide has been reduced, refired at 1200‹ C. in an oxygen containing atmosphere. |
