| 摘要 |
1386244 Beta-alumina UNITED KINGDOM ATOMIC ENERGY AUTHORITY 23 Aug 1972 [26 July 1971] 35003/71 Headings ClJ and C1A [Also in Division H1] #-Alumina is obtained by calcining a waterdispersible alumina gel doped with sodium ions. The doped gel may be formed from the corresponding doped sol, the sol being doped by addition of sodium water-soluble salts and optionally salts of magnesium and other metals. Preparation of the sol may involve denitration of hydrated aluminium nitrate or substitution of chlorine ions in aluminium chlorhydrate solution. In Example 1 aluminium nitrate, Al(NO 3 ) 3 9H 2 O, was heated to give off H 2 O and HNO 3 forming a powder, AlONO 3 .2H 2 O, the powder then being dispersed in boiling water to give a nitrate sol which was then evaporated to an alumina sol. In Example 2 aluminium chlorhydrate was poured into NH 4 OH to form an alumina gel, this being dispersed in HNO 3 to give a sol and concentrated to give an alumina sol. In Example 3 doped sol was dispersed in "Genklene" (Registered Trade Mark) containing a surfactant, the resultant spherical particles gelled by "Primene" (Registered Trade Mark), washed, oven dried and calcined at 700- 1500‹ C. Example 4 describes a similar method for preparing 15 Á spheres of #-alumina and the preparation of an artifact by plasma spraying and firing. |
