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Regenerating Electroless Nickel and Cobalt Solutions

IP.com Disclosure Number: IPCOM000094185D
Original Publication Date: 1966-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Smith, RS: AUTHOR

Abstract

In electroless nickel, cobalt, and nickel-cobalt electroplating baths, the hypophosphite ion is converted to phosphite ion and, by accumulating, can eventually cause degeneration of the bath. Thus, it is necessary to regenerate the bath and remove the phosphite ions by the following method. 1) Ammonium hydroxide is added to the electroless plating bath to raise the pH to about 9.5, 2) Calcium hydroxide next is added in large quantities to form calcium phosphite which precipitates from the bath, and 3) To remove the excess calcium without lowering the temperature of the bath, carbon dioxide is bubbled through the bath to form calcium carbonate which precipitates from the bath.

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Regenerating Electroless Nickel and Cobalt Solutions

In electroless nickel, cobalt, and nickel-cobalt electroplating baths, the hypophosphite ion is converted to phosphite ion and, by accumulating, can eventually cause degeneration of the bath. Thus, it is necessary to regenerate the bath and remove the phosphite ions by the following method. 1) Ammonium hydroxide is added to the electroless plating bath to raise the pH to about 9.5, 2) Calcium hydroxide next is added in large quantities to form calcium phosphite which precipitates from the bath, and 3) To remove the excess calcium without lowering the temperature of the bath, carbon dioxide is bubbled through the bath to form calcium carbonate which precipitates from the bath.

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