| 摘要 |
1,137,493. Beryllia, thoria, urania, iron oxide. CANADIAN PATENTS & DEVELOPMENT Ltd. 14 Dec., 1965 [14 Dec., 1964], No. 53086/65. Heading C1A. Dense'hard metal oxides are made by heating a composition containing a compound, or mixture of compounds, which on decomposition yields one or more of beryllia, thoria, urania and iron oxide, to a temperature of 300-1000‹ C. under a pressure of 2,000-50,000 psi to cause a molecular decomposition. The oxideforming compounds, prior to heating under pressure, can be mixed with metal or non- metallic fibres, rock, sand and also metal powder so as to produce a cermet. The oxideforming compound may be a carbonate, bicarbonate, sulphate, nitrate, hydroxide or hydrated hydroxide; the use of iron carbonate and ammonium diuranate is exemplified. The composition can be formed under pressure in a die with heating taking place whilst the composition is still in the die. The composition can be cycled through the temperature at least twice. In the example the composition is heated by induction using a graphite die which functions both as a susceptor and a pressing component. The composition can be hot pressed in an atmosphere of air, nitrogen or argon. The pressure can be applied by hammer blows or a continuous pressure transmitting device. The hot-pressed oxide product can be reheated, e.g. to 750‹ to 1500‹ C. with or without pressure. |
