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Salt Fog (MIL-STD-810f) vs. Salt Spray (IEC 60512-6 test 11f)

Q. Would someone please itemize the differences in these two tests? We are using a connector fabricated in Europe that passes the IEC 605126 Salt Spray test and we need to test this connector to the MIL-STD-810 [on DLA] Salt Fog test. Anyone see any issues with the connector passing our tests?

James Jeevz
Military Contractor - Long Beach, California, USA
2005

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Q. I was tasked with comparing ASTM B117 Salt Spray with "the IEC equivalent" and it is like comparing lemons with limes. For example the salt solution in both is essentially identical but ASTM salt spray exposure is continuous while IEC 60068-2-52:1996, Part 2-11 - Test Kb: Salt Mist, cyclic, alternates 2 hours of salt spray exposure with a dwell period (variable according to desired Severity) in a humid environment.

And IEC test duration is consistent, depending on Severity, (E.g. Severity 1 = 7 days, Severity 2 = 3 days) but ASTM B117 defines the salt spray environment, not how long the part must survive in it which, in the case of zinc plating, is defined by ASTM B633.

It would be nice if the plating manufacturers published comparative data (ASTM vs. MIL vs. IEC) but I have yet to find any. Per James Watts suggestion Step one is to get a copy of both salt spray specifications and compare them.

Adrian Nicholas
shipboard telecoms - Concord, California
2007

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But the thing is, just as accelerated corrosion tests don't correspond to real life (because the corrosion mechanism is fundamentally different), the accelerated tests may not correspond to each other either.

Although the correspondents probably understand this, for the benefit of readers who may not: when metals corrode, the tarnishes & corrosion products that form on them may be worthless and troublesome like the fluffy, hygroscopic rust that forms on steel ... but in other cases the corrosion products can form a tight, adherent skin which may have great capability of retarding further corrosion under real world circumstances. Galvanized zinc finishes, for example, perform quite poorly in a salt spray chamber; but in real life, where the zinc can react with the carbon dioxide in the air over the months and years, those zinc carbonate corrosion products can form glassy, impervious, self-protecting films that can last 50 to 100 years and more with no maintenance.

Use accelerated testing to get an early indication that a process is going out of control, but never to try to compare the corrosion resistance of one material to another.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007