ASTM-B556 › Historical Revision Information
Standard Guide for Measurement of Thin Chromium Coatings by Spot Test
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Scope
1.1 This guide covers the use of the spot test for the measurement of thicknesses of electrodeposited chromium coatings over nickel and stainless steel with an accuracy of about ±20 % (Section 9). It is applicable to thicknesses up to 1.2 μm.
Note 1—Although this test can be used for coating thicknesses up to 1.2 μm, there is evidence that the results obtained by this method are high at thicknesses greater than 0.5 μm. In addition, for coating thicknesses above 0.5 μm, it is advisable to use a double drop of acid to prevent depletion of the test solution before completion of the test.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Significance and Use
The thickness of a decorative chromium coating is often critical to its performance.
This procedure is useful for an approximate determination when the best possible accuracy is not required. For more reliable determinations, the following methods are available: Methods B 504, B 568, and B 588
This test assumes that the rate of dissolution of the chromium by the hydrochloric acid under the specified conditions is always the same.
Keywords
chromium-coatings; coating thickness; nickel-electrodeposition; spot test; stainless steel; steel products-electrodeposited coatings; ICS Number Code 25.220.40 (Metallic coatings)
To find similar documents by ASTM Volume:
02.05 (Metallic and Inorganic Coatings; Metal Powders and Metal Powder Products)
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Document Number
ASTM-B556-90(2007)
Revision Level
1990 R07 EDITION
Status
Superseded
Modification Type
Reapproval
Publication Date
Feb. 1, 2007
Document Type
Guide
Page Count
3 pages
Committee Number
B08.10