A process for the manufacture of a thin ceramic core for use in precision casting, comprising the following steps:
(a) preparing a solution comprising, by mass, 30% of a ceramic material and 70% of a binder material, said ceramic material consisting of, by mass, 70% silica and 30% zircon, and said binder material consisting of, by mass, from 50% to 70% of a solvent, from 15% to 20% of a binding agent, a plasticizer formed by from 5% to 10% of a first product and from 10% to 15% of a second product, and 1% of a dispersing agent;
(b) casting said solution on a support to form a band of said solution having a uniform thickness;
(c) drying said band formed in step (b);
(d) shaping said band in a mold;
(e) preheating said band in said mold to 100.degree. C. for 30 minutes;
(f) pressing said band in said mold under a pressure of 40 MPa for 3 minutes;
(g) baking the component obtained in step (f) in a ceramic preform under the temperature and duration conditions determined for the ceramic material; and,
(h) impregnating the core obtained in step (g) by an organic resin or polymer.
2. The process as claimed in claim 1, wherein, between steps (a) and (b), said solution obtained in step (a) is subjected to a deaeration step comprising rotating said solution at a low speed of 1 to 2 revolutions per minute for at least 48 hours.
3. The process as claimed in claim 1, wherein said baking in step (g) is carried out at 1250.degree. C. for 4 hours.
4. The process as claimed in claim 1, wherein the thin ceramic core obtained is assembled with at least one other thin ceramic core and/or on a thick central core obtained by a conventional core manufacturing method.
5. The process as claimed in claim 4, wherein the said cores are assembled by adhesive bonding.
6. The process as claimed in claim 5, wherein said adhesive bonding is carried out by means of a ceramic adhesive based on colloidal silica and a mullite based mineral filler in proportions, by mass, of 30 to 70.
7. The process as claimed in claim 4, wherein said cores are assembled by means of a mechanical connection of the mortise-and-tenon type.
8. The process as claimed in claim 4, wherein said cores are assembled by means of a quartz tube passing through the cores and retained by means of ceramic adhesive.