Gold Finish Plating Specification MIL-G-45204
Gold is by far the most popular plating metal. Functional, practical, effective. Superior corrosion resistance, spectacular aesthetics. Yellow to orange color depending on proprietary process used. Will range from matte to bright finish depending on basis metal. Good corrosion resistance, and has high tarnish resistance. Provides a low contact resistance, and is a good conductor. Has excellent solder-ability. Unless otherwise specified, an intermediate nickel plate is required on copper base alloys or copper plated surfaces prior to the gold plating.
Type I 99.7% gold min.
Type II 99.0% gold min.
Type III 99.9% gold min.
Class 00 .00002" min.Grade A 90 Knoop max.
Class 0 .00003" min.Grade B 91-129 Knoop
Class 1 .00005" min.Grade C 130 - 200 Knoop
Class 2 .00010" min.Grade D above 200 Knoop
Class 3 .00020" min.
Class 4 .00030" min. Type I (Grades A, B or C)
Class 5 .00050" min. Type II (Grade B, C or D)
Class 6 .00150" min.Type III (Grade A only)
here are several types of gold plating used in the electronics industry: