NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Copper Oxide Precipitates in NBS Standard Reference Material 482
Published
Author(s)
Eric S. Windsor, R Carlton, John G. Gillen, Scott A. Wight, David S. Bright
Abstract
Copper oxide has been detected in the copper containing alloys of Standard Reference Material (SRM) 482. This occurrence is significant because it represents heterogeneity within a standard reference material that was certified to be homogeneous on a micrometer scale. Oxide occurs as elliptically to spherically shaped precipitates whose size differs with alloy composition. The largest precipitates occur in the Au20-Cu80 alloy and range in size from submicrometer up to 2 υm in diameter. Precipitates are observed using light microscopy, electron microscopy and secondary ion mass spectrometry (SIMS). SIMS has demonstrated that the precipitates are present in all wires that contain copper. Only the pure gold wire is precipitate free. Initial results from the analysis of the Au20-Cu80 alloy indicate that the percentage of precipitates is less than 1% by area. Electron probe microanalysis (EPMA) of large (2 υm) precipitates in this same alloy indicates that precipitates are detectable by EPMA and that their composition differs significantly from the certified alloy composition. The small size and low percentage, of these oxide precipitates minimizes the impact they have upon the intended use of this standard for electron probe microanalysis. The heterogeneity caused by oxide precipitates however may preclude the use of this standard for automated EPMA analyses and also for other microanalysis techniques.
copper-gold alloy, electron probe microanalysis, metallography, oxide inclusions, sample preparation, secondary ion mass spectrometry, Standard Reference Material 482
Windsor, E.
, Carlton, R.
, Gillen, J.
, Wight, S.
and Bright, D.
(2002),
Copper Oxide Precipitates in NBS Standard Reference Material 482, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD
(Accessed October 2, 2025)