Electro galvanized coating thickness

A. Hi, Rajesh. There is no minimum thickness, although there is probably a minimum beneficial thickness in the neighborhood of .0001". The maximum practical thickness is probably somewhere around .0006 to .0008". You might want to consider mechanical galvanizing or hot-dip galvanizing above that thickness. In fact, due to hydrogen embrittlement issues, you may want to consider mechanical plating in any event. But please describe your situation rather than posing your inquiry in abstract fashion, because hypothetical questions can never be properly answered without a hundred ifs, ands, and buts. Thanks.

Regards,

A. Hi Mike. 5-12 microns will give roughly twice the corrosion protection of 3-5 microns.

Regards,

A. Hi Mike. I know that this kind of answer isn't very satisfying, but the question itself is fraught with ambiguities for lots of reasons. First, salt spray testing is a QA assurance mechanism, not a predictor of real life. Second, salt spray testing of zinc coatings is misleading 100% of the time because it doesn't allow the zinc carbonate corosion products to form that offer the actual long term protection to zinc coated products. Third, the salt spray performance is as dependent (if not more so) on the chromate conversion coating and topcoat than on the zinc plating. I think the best answer is that a 4 micron zinc coating is only for "mild" corrosion conditions (indoors) whereas 10-12 microns might offer "moderate" corrosion protection, such as for underhood automotive components. You could probably request a coating suitable for 96, 128, or 192 hours of salt spray, and you'd probably see inconsistent results with 3 microns, but good results with 8 microns or more.

Regards,