| 摘要 |
PURPOSE:To produce precision molds simply and easily by the use of inexpensive materials by mixing binders and a good electrical conductor material with zircon type powder treated in an electrolyte soln., coating the mixture on the surface of a pattern, and heating the same electrically to allow the coating to harden. CONSTITUTION:Zircon type sand or fine grain sand is used for the aggregate of refractory materials, and the sand is beforehand treated in an electrolyte soln. Inorg. and org. binders are used, for which a part or a number of kinds of water glass, bentonite, starch, CMC, hexametaphosphoric acid are used. As the good electrical conductor, 1 or 2 kinds of compds. among Ca, Na, K, Mg, Al, etc. are added in the form of an aq. soln. The refractory material 2 obtd. by mixing the above-mentioned materials is coated or packed on the surface of a wooden pattern 1 and is heated electrically via electrodes 3, 3, whereby the material is heated quickly and the hardened layer is formed. The pattern 1 is removed, and the precision mold is obtained. |
