| 摘要 |
1,229,225. Refractory moulds. MICROFUSION S.A. 21 Nov., 1968 [23 Nov., 1967], No. 55218/68. Heading B5A. [Also in Division C1] Moulds for pouring of highly reactive materials are produced by coating a model with a layer of fluid composition, applying a powder thereto and hardening the first layer, repeating the coatings and hardening until sufficiently thick, extracting the model and baking the product mould, the fluid composition comprising a filler of graphite or superactivated carbon suspended in a binder of pH value equal to 2 at most, the binder also comprising colloidal silica or alumina. In an alternative embodiment, only the layers adjacent the model are formed by the composition, the external layers being constituted by a different composition capable of reacting with the highly reactive materials. The powder may be graphite or superactivated carbon. Hardening of the fluid composition may be effected by gelation with ammonia. |
