JIS defines the requirements on plating applied over iron, copper, or their alloy substrates, in order to add solder wettability, electrical properties, and corrosion resistance to electrical/electronic components, as described hereinafter.

(1)Type and grade of plating

[Table 1] Chemical composition (%) of plating film

[Table 2] Type and grade of plating

(2)Appearance of plating

The visual inspection will be performed in the same manner as the other types of plating. The plating surface should be flat and free from defects, including burnt or swollen areas, lumps, scratches, pits, flaking, cracks, and exposure of substrates or undercoat.

(3)Chemical composition of plating film

The chemical composition of plating film can be measured by the fluorescence X-ray analysis, and so on.

(4)Minimum thickness of plating film

The plating thickness can be measured by instruments, such as a fluorescent X-ray film thickness meter and a magnetic film thickness meter. In both cases, the values shown in Table 2 must be satisfied.

(5)Plating adhesion

It should be measured by conducting an adhesion-tape test, a bending test, a thermal-shock test, and so on.

(6)Corrosion resistance of plating

The corrosion resistance must be verified to be at least rating number 9 by conducting a neutral salt spray test or a test method agreed between the parties concerned.

(7)Solder wettability of plating

Just like the case of silver coatings applied for engineering purposes, the following solder wettability test must be conducted:Immerse the flux-treated sample into a soldering bath heated at 250°C for three seconds, and shake the residual liquid off. Check the soldering surface and evaluate the property.

(8)Stress relief before plating

To include a heat treatment process for reducing residual stress on steel/copper alloy products before plating, the conditions must be determined and agreed by the parties concerned.

(9)Plating name and symbol

●Ep-Cu/Ni/Sn(75)-Pb5

Tin (75%)-lead alloy plating with a thickness of 5 µm over nickel base-coat plating on a copper substrate

●Ep-Cu/Ni/Sn(75)-Pb[3]

Type I/Grade 3 tin-lead alloy plating deposited over nickel base-coat plating on a copper substrate

●Ep-Fe/Cu/Sn(75)-Pb5

Tin (75%)-lead alloy plating with a thickness of 5µm over copper base-coat plating on an iron substrate