Gold Plating Standards

Before the government controls on gold prices were lifted by Nixon, gold plating of electronics was relatively common.
Before the government controls on gold prices were lifted by Nixon, gold plating of electronics was relatively common. | Source

ASTM Standards for Gold Plating

ASTM B487 is the test procedure for examining the thickness of a metal coating using a microscope. This standard has been adopted by the U.S. Department of Defense for gold plating.

ASTM B567 gives the process of measuring the gold plating thickness using the beta backscatter method. ASTM B568 is the test method for measuring the thickness using an X-ray. ASTM E84 is the test procedure for determining the hardness of the gold plating.

ASTM B477 is the standard for gold-silver-nickel alloy used for electrical contacts. ASTM B522 is the standard for gold-silver-platinum alloy used for electrical contacts. ASTM B594 is the specification for copper-gold alloy used in electrical contacts. ASTM B541 is the standard for gold alloy used in electrical contacts.

Military Specifications for Gold Plating

MIL-DTL-45204 is the military standard for electro-deposited gold plating. Revision D of MIL-DTL-45204 was published in 2007. Type 1 plating must be at least 99.7% gold. Type 2 must be at least 99% gold. Type 3 must be 99.9% gold. MIL-DTL-45204 also assigns grades based on hardness. Grade A hardness is no greater than 90 Knoop.

Grade B has a hardness of 91 to 129 Knoop. Grade C gold plating has a hardness of 130 to 200 Knoop. Grade D has a hardness of 201 Knoop or greater. The classes for the gold plating thickness range from Class 00 to Class 6. Class 00 has a minimum thickness of 0.00002 inches, while Class 0 has a thickness of at least 0.00003 inches. Class 6 is the thickest with a minimum thickness of 0.00150 inches.

MIL-G-14548 was a gold plating standard used by the DoD in the 1950s. MIL-G-19788 was a military specification for electro-deposited gold plating. It was cancelled in 1977. Both of these standards are superseded by MIL-DTL-45204.

ISO Gold Plating Standards

ISO 27874 is a standard for electro-deposited gold and gold alloy coatings. ISO 27874 covers both the material specifications and its testing. ISO 8654 gives the range of colors and definitions of the different designations of gold alloys. The method to determine the gold's color is done using spectral reflectance.

ISO 11426 is the standard for the fire assay method of determining the gold content in alloys used in jewelry, including gold plated jewelry. This is also called the Cupellation method.

ISO 10713 is the standard for gold alloy used to coat jewelry.

ISO 4524 contains several parts. Each part describes a different test on electro-deposited gold coatings. IOS 4524-3 describes the electrographic tests used to check gold coatings for porosity. ISO 4524-5 gives the standard method of measuring the adhesion of the gold coating to the underlying surface. ISO 4524-6 determines whether there are residual salts in the gold coating.

ISO 15720 measures the porosity of gold and palladium coatings using gel-bulk electrography.

Related Gold Plating Standards

SAE AMS2425 is the Society of Automotive Engineer's standard for gold plating components for thermal control. SAE AMS2425 has been adopted by ANSI.
IPC 4552 is a standard for electro-less nickel and immersion gold or ENIG plating for printed circuit cards, also called PCBs. IPC 4552 is ANSI approved.
IPC TM-650 2.3.24 is a standard for using chemicals to determine the porosity of gold plating. IPC TM-650 5.1.110 is a standard for analyzing gold electroplating solutions that are acidic or neutral. IPC TM-650 5.1.112 is used to analyze cyanide gold electroplating solutions.

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