| 摘要 |
The invention relates to a process for the production of a shell mould, comprising the sequential steps of: (i) dipping a preformed expendable patte rn finto a slurry of refractory particles and colloidal liquid binder whereby t o form a coating layer on said pattern, (ii) depositing particles of refractor y material onto said coating, and (iii) drying, steps (i) to (iii) being repeated as often as required to produce a shell mould having the required number of coating layers, characterised in that during at least one performance of step (ii) the particles of refractory material have been pre~mixed with a gel-forming material whereby to coat at least a portion of said refractory particles with said gel forming material such that after contact with the coating layer moisture is absorbed by the gel-forming material thereby causing gellation of the colloidal binder so reducing the time required for drying in step (iii).
|
