Method for removing volatile components from a gel-cast ceramic article
AssigneeGeneral Electric Company
InventorsFrederic Joseph Klug, Sylvia Marie DeCarr
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Abstract
A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.
Claims26
A method of removing substantially all of a volatile component in a green, volatile-containing gel-cast ceramic article cast from a gel-casting slurry, the method comprising the steps of:
- (a) providing the gel-casting slurry;
- (b) casting the article from the gel-casting slurry in a mold;
- (c) gelling the gel-casting slurry to form the gel-cast ceramic article in the mold;
- (d) releasing the gel-cast ceramic article from the mold;
- (e) freezing the gel-cast ceramic article after releasing the gel-cast ceramic article from the mold;
- and
- (f) subjecting the frozen gel-cast ceramic article to a vacuum for a sufficient time to freeze-dry the gel-cast ceramic article.
A method for fabricating a gel-cast ceramic article suitable for use as a core in the investment casting of directionally solidified eutectic and superalloy materials, the method comprising the steps of:
- (i) preparing a ceramic slurry which comprises:
- (A) at least one ceramic component, and
- (B) a solution of a polymerizable binder in a liquid;
- (ii) forming the slurry into a gel-cast green product of an article-shaped body;
- (iii) allowing the slurry to gel;
- (iv) releasing the gel-cast green product from the mold;
- (v) freezing the gel-cast green product after releasing the gel-cast ceramic article from the mold;
- (vi) subjecting the frozen product to a vacuum for a sufficient time to freeze-dry the product;
- and
- (vii) heating the gel-cast green product in an oxygen-containing atmosphere to form a sintered ceramic article.
Dependencies are inferred from the claim text.