ASTM Designation: B 488

Electrodeposited Coatings of Gold

Purity

Mass Percent Gold Minimum ASTM TypeMIL-G-45204
99.90 1 III
99.70 2 I
99.00 3 II

Hardness

Knoop Hardness Range ASTM TypeMIL-G45204
90 HK25 maximum A A
91-129 HK25 B B
130-200 HK25 C C
200 HK25 D D

Relationship between Purity and Hardness

ASTM Code
I A, B and C
II B, C and D
III A only

Coating Thickness

Class Minimum Thickness
0.25 microns 0.25 microns
0.50 microns B, C and D
0.75 microns 0.75 microns
1.0 microns 1.0 microns
1.25 microns 1.25 microns
2.5 microns 2.5 microns
5.0 microns 5.0 microns