Browse Prior Art Database

System for Automatic Sensing and Control of Formaldehyde in an Additive Plating Bath

IP.com Disclosure Number: IPCOM000042692D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Markovich, V: AUTHOR [+3]

Abstract

The system shown automatically senses and controls formaldehyde in an additive bath. This system operates automatically with all electrical input and output with no need to add external reagents. The basic detecting reaction is the oxidation of formaldehyde by an electrically generated oxidant (either iodine or bromine internally generated in the detecting cell): HCH = O + I2 + OH- T HCOO- + 2I- + 2H+ (1) A detecting cell is shown in the figure. An electrolyte is continuously circulated at constant flow by action of a pump. The electrolyte has a composition similar to the additive bath's, with the addition of 0.01M KBr + 0.01M KI. The electrolyte circulates downwards through an oxidant generator system and a detector system of a cell. The oxidant generator is a platinum wire Pt1 .

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System for Automatic Sensing and Control of Formaldehyde in an Additive Plating Bath

The system shown automatically senses and controls formaldehyde in an additive bath. This system operates automatically with all electrical input and output with no need to add external reagents. The basic detecting reaction is the oxidation of formaldehyde by an electrically generated oxidant (either iodine or bromine internally generated in the detecting cell): HCH = O + I2 + OH- T HCOO- + 2I- + 2H+ (1) A detecting cell is shown in the figure. An electrolyte is continuously circulated at constant flow by action of a pump. The electrolyte has a composition similar to the additive bath's, with the addition of
0.01M KBr + 0.01M KI. The electrolyte circulates downwards through an oxidant generator system and a detector system of a cell. The oxidant generator is a platinum wire Pt1 . A voltage is applied between Pt1 and a silver electrode Ag1, making Pt1 positive. Therefore, the amount of oxidant generated at Pt1 is: 2I- - 2e T I2 oxidant generation (2) The I2 generated in (2) travels down with the electrolyte until it encounters a detecting system which is a Pt2 screen comprising a cathode connected to another silver electrode Ag2 . Here, all the I2 generated in (2) is reduced to I-: I2 + 2e T 2I- oxidant detection (3) The net result is that no change occurs in the system as the electrolyte circulates continuously through the cell. However, if the detector system is connected to a ...