This section of JIS defines silver coatings with the thickness of at least 0.5 µm on a metal or nonmetal substrate, produced for engineering purposes, including electrical/electronic products, machinery and other functional components.

(1) Appearance

The significant surfaces of the plating should be free from defects of polish, radiance, color shades, and imperfections as roughness, burnt parts, pits, dendrites on the edges, plating defects as substrate or undercoat exposure, adhesion failure as swelling or external flaws including smudges and scratches.

(2) Plating thickness

[Table] shows the minimum plating thickness of significant surfaces.

[Table] Classification by the minimum plating thickness

(3) Silver content

If the silver content in plating is specified, perform a test agreed between the parties concerned and display the value including the first decimal place.

(4) Porosity of plating

If the porosity of plating is specified, expose the sample into nitric acid vapor and check the number of corrosion points. Place a degreased and dried sample in the desiccator containing nitric acid. Leave it in there for one hour and measure the number of corrosion points per 1cm² as the porosity.

(5) Color fastness of plating

For anti-tarnish treated plating with its color fastness specified, evaluate the property by measuring the time until a discoloration occurs after dipping the sample into the ammonium sulfide solution (color fastness test).

(6) Corrosion resistance and adhesiveness of plating

To measure the corrosion resistance, perform testing such as a neutral salt spray test, a CASS test, or a sulfur dioxide test. To measure the adhesiveness, perform testing such as a tape test, a thermal-shock test, or a bend test.

(7) Residual salt on significant plating surfaces

If contamination by residual salts on the plating film is the issue, perform a test by a method agreed between the parties concerned.

(8) Other characteristics

The other characteristics of plating films include the followings: 1) solder wettability of plating; 2) electrical properties of plating; 3) plating hardness; 4) undercoat; 5) abrasion resistance. Depending on the agreement between the parties concerned, some of these properties may be requested.

(9) Plating name and symbol

Ep-Cu/Ni b, E-Ag 5 b

Bright industrial silver coating of 5 µm or more over bright nickel undercoat on a brass substrate

Ep-Cu/E-Ag 20/AT

Industrial silver plating of 20 µm or more with anti-tarnish chromate treatment on a brass substrate

Ep-Zn/Cu 10, Ni 5 b, E-Ag 5 b

Industrial bright silver coating of 5 µm or more over 10 µm copper undercoat and 5 µm bright nickel undercoat on a substrate made of zinc die cast alloy