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Ion Exchange Membrane for Anode Protection

IP.com Disclosure Number: IPCOM000083275D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Mansbridge, DS: AUTHOR

Abstract

The conventional porous diaphragm often employed to separate the anolyte and catholyte in an electroplating bath is replaced by an ion-exchange membrane.

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This is the abbreviated version, containing approximately 100% of the total text.

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Ion Exchange Membrane for Anode Protection

The conventional porous diaphragm often employed to separate the anolyte and catholyte in an electroplating bath is replaced by an ion-exchange membrane.

Specifically, a cationic selective ion-exchange membrane (commercially available as Permaflex C from British Drug Houses is employed in a chromium plating bath to protect the platinized titanium anode from the action of the electrolyte. The electrolyte is a chromium (III) - thiocyanate complex prepared from chromium perchlorate and sodium thiocyanate.

An unprotected anode reacts with the electrolyte, resulting in a serious decrease in solution pH and a drop in deposit quality. However, surrounding the anode with a sodium perchlorate solution of pH 2.0, enclosed in a Permaflex C bag, allows cations but not anions to pass, thereby protecting the anode and permitting the bath to be operated for much longer periods with improved deposit quality.

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