Method for removing volatile components from a ceramic article, and related processes
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.
Claims11
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) a 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) pre-drying the gel-cast green product under conditions of high humidity;
- (v) freezing the gel-cast green product after pre-drying the gel-cast ceramic article;
- (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.