Leaching of ceramic materials
AssigneeROLLS-ROYCE plc
InventorDavid Mills
Life of this patent
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Abstract
The article together with the alumina core in situ is placed in a sealable vessel containing a concentrated aqueous potassium hydroxide leaching liquor at a temperature immediately below its normal atmospheric boiling point. The vessel is sealed and the pressure within the vessel is reduced to less than atmospheric pressure so as to induce boiling and agitation of the leaching liquor within the passage in the article. The pressure in the vessel is raised to atmospheric pressure and finally spent leaching liquor together with leached alumina core is removed from within the article.
Claims16
A method of leaching a ceramic material from a passage within an article, the method comprising the steps of,
- (a) placing the article together with the ceramic material in situ therein in a sealable enclosure, in which there is provided a leaching liquor at a temperature immediately below its normal atmospheric boiling point,
- (b) sealing the enclosure,
- (c) for a first period of time, maintaining the liquor in a quiescent state in contact with the ceramic material,
- (d) reducing the pressure within the enclosure to less than atmospheric pressure so as to induce boiling and agitation of the leaching liquor within said passage within the article for a second period of time, thereby to enhance leaching of the ceramic material within the passage,
- (e) raising the pressure within the enclosure to atmospheric pressure, and returning the liquor to a quiescent state,
- (f) removing spent leaching liquor together with leached ceramic material from within the article.
Dependencies are inferred from the claim text.