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Metallographic Analysis of Electrodeposited Chromium

IP.com Disclosure Number: IPCOM000075139D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brutsman, W: AUTHOR [+2]

Abstract

The crack pattern in electrodeposited chromium is an important indicator of the physical nature of the plated metal. Normally, examination of the deposited metal at magnifications as great as 500X fails to reveal the nature and extent of the intrinsic crack structure. However, by electrochemically etching the plated surface with sodium carbonate, the chromium crack pattern becomes evident at magnifications of about 500X. If limited to a short duration, the test is nondestructive since the crack areas are attacked selectively.

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Metallographic Analysis of Electrodeposited Chromium

The crack pattern in electrodeposited chromium is an important indicator of the physical nature of the plated metal. Normally, examination of the deposited metal at magnifications as great as 500X fails to reveal the nature and extent of the intrinsic crack structure. However, by electrochemically etching the plated surface with sodium carbonate, the chromium crack pattern becomes evident at magnifications of about 500X. If limited to a short duration, the test is nondestructive since the crack areas are attacked selectively.

A typical etch solution, and conditions for electrochemical etching, with the plated member as the anode on a DC power source, are: Na(2)CO(3) 50 gm/1

Temperature 120 degrees F.

Cathode Stainless Steel

Current 1.25 asi

Time 60 seconds. Using this technique, chromium plated magnetic recording heads, for example, can be tested.

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