Method for removing Y.sub.2 O.sub.3 or Sm.sub.2 O.sub.3 cores from castings
AssigneeGeneral Electric Company
InventorsRonald H. Arendt, Irvin C. Huseby, Marcus P. Borom
Life of this patent
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Abstract
A weakly acid solution of either NH.sub.4 NO.sub.3, NH.sub.4 Cl, NH.sub.4 HSO.sub.4, CH.sub.3 COOH or equimolar CH.sub.3 COOH -- CH.sub.3 COONa is employed to remove cores of either Y.sub.2 O.sub.3 or Sm.sub.2 O.sub.3 from castings of advanced superalloy materials. A molten salt bath may be used thereafter to remove reaction products formed by the reaction of the materials of the core and the metal casting.
Claims22
A method for in-place leaching of ceramic materials in contact with a casting comprising an advanced superalloy material comprising
- (a) preparing an aqueous weak acid leaching solution of a weak acid material which is one selected from the group consisting of NH.sub.4 Cl, NH.sub.4 HSO.sub.4, CH.sub.3 COOH and equimolar CH.sub.3 COOH -- CH.sub.3 COONa, wherein the molarity of the solution is from about 0.1 molar to about 15 molar;
- (b) heating the solution to a predetermined temperature;
- (c) placing an article consisting essentially of a ceramic material which is one selected from the group consisting of Y.sub.2 O.sub.3 and Sm.sub.2 O.sub.3 in the heated solution, and
- (d) preferentially attacking the ceramic material with the heated solution to dissolve at least a part of the ceramic material into the heated solution.
A method for in-place leaching of ceramic materials comprising
- (a) preparing an aqueous weak acid leaching solution of NH.sub.4 NO.sub.3, wherein the molarity of the NH.sub.4 NO.sub.3 solution may range from 0.1 molar to saturation;
- (b) heating the solution to a predetermined temperature;
- (c) placing an article consisting essentially of a ceramic material which is one selected from the group consisting of Y.sub.2 O.sub.3 and Sm.sub.2 O.sub.3 in the heated solution;
- (d) preferentially attacking the ceramic material to dissolve at least a part of the ceramic material into the heated solution as a nitrate product;
- (e) collecting at least the products of the leaching action as nitrates, and
- (f) heating the collected nitrates at a temperature of approximately 800.degree. C. to convert the nitrates to at least a ceramic oxide.
Dependencies are inferred from the claim text.