| 摘要 |
1,234,575. Moulding plastic substances. R. A. BROWN, and C. A. BROWN. 6 Aug., 1968, No. 37373/68. Heading B5A. [Also in Divisions B3 and C3] An investment shell mould comprising a laminated shell including facing and back-up portions, at least the facing portion being composed of alternate layers of (a) a mixture of at least one metal selected from columbium, molybdenum, tantalum and tungsten and a refractory metal oxide binder therefor, and (b) finely divided particles of at least one metal selected from columbium, molybdenum, tantalum and tungsten is produced by: (a) dip coating a disposable pattern in a liquid suspension of at least one finely divided metal selected from columbium, molybdenum, tantalum and tungsten and a binder selected from the refractory metal oxides and the refractory metal compounds pyrolisable to refractory metal oxides, (b) stuccoing the dip coated pattern with at least one of the said finely divided metals, (c) drying the dip coated and stuccoed pattern, (d) repeating the dip coating, stuccoing and drying sequence with the same and/or different constituents until a shell mold of the desired thickness has been built up about the disposable pattern, (e) removing the disposable pattern from the shell mold, and (f) firing the shell mold at a temperature below the sintering temperature to bond together the finely divided metal particles. |
