October 2017 Archives

JIS defines the significant surfaces of gold and gold alloy plating for decorative purposes, which are applied over watches, personal ornaments and miscellaneous goods, as described hereinafter.

(1) Term definition

1. Gold plating

Electroplated coating consisting of the gold content of 99.9% or more and generally classified in the soft plating category.

2. Gold alloy plating

Plating consisting of the gold content of at least 58.5% but less than 99.9% and usually harder than gold plating.

3. Multilayer plating

Two or more layers of coatings that are plated by materials in varying gold content.

(2) Appearance

The requirements of silver plating for engineering purposes also apply to the appearance of gold plating. The appearance is especially important for this type of plating.

(3) Plating thickness

[Table] shows the classifications by the minimum plating thickness.

[Table] Classification by the minimum plating thickness

(4) Gold content

If the gold content is specified at a particular value (layer-specific values for multilayer plating), the content will be measured by a chemical method that is defined separately.The specified value must be satisfied.

(5) Porosity of plating

If the porosity is specified, it must be verified by a nitric acid aeration test.

(6) Corrosion resistance of plating

If the corrosion resistance is specified, it must be evaluated by a neutral salt spray test or a CASS test.

(7) Plating adhesion

The plating adhesion can be verified by test methods including a tape test and a thermal-shock test.

(8) Others

In addition to the conditions mentioned here, the following characteristics may be required:
1. Plating thickness, 2. Abrasion resistance of plating, 3. Conditions of the substrate, 4. Type and thickness of base-coat plating, etc.

(9) Plating name and symbol

●Ep-Cu/Nib, D-Au5

Decorative gold plating with a thickness of at least 5 µm over bright nickel base-coat plating on a brass substrate

●Ep-Zn/Cu10, Ni5b, D-Au0.5/PA

Zinc die casting alloy substrate, 10 µm-thick copper base-coat plating, 5 µm-thick bright nickel base-coat plating, and decorative gold plating of at least 0.5 µm thickness over it, with transparent urethane finish

●Ep-Fe/Nib, D-Au (60.0) 10, D-Au(90.0) 3

Two-layer plating consisting of decorative gold alloy plating (gold content of 60%) with a thickness of at least 10 µm and decorative gold alloy plating (gold content of 90%) with a thickness of at least 3 µm over bright nickel base-coat plating on a steel substrate

The JIS grades of corrosion resistance for plating must be at least Grade 9 after the hours of each testing specified in Table.

[Table] Corrosion resistance of nickel and chrome plating

Unit: Hour

* Note 1) Ferroxyle test
This testing is designed for checking the corrosion resistance of copper/nickel plating or nickel/chrome plating applied over steel substrates. In this test, paste a filter paper soaked with ferroxyl test solution over the significant surface and peel it after five minutes. The anti-corrosion properties can be measured by the blue spots indicating the presence of iron complex, which appear on the paper.

* Note 2) Operating environment
A: Highly corrosive outdoor environment, such as coastal areas and industrial zones
B: Normal outdoor environment, such as rural zones and residential areas
C: Highly humid indoor environment, such as bathrooms and kitchens
D: Normal indoor environment, such as inside of houses and offices

This standard defines the types of nickel and chrome plating applied on aluminum and aluminum alloy substrates for decorative and anti-corrosion purposes, as well as the plating thickness of the significant surfaces and the corrosion-resistance properties.(The corrosion resistance properties are described in another section.)

[Table] Nickel and chrome plating on aluminum alloy substrates

This standard defines the types of plating applied on zinc alloy die casting for decorative and anti-corrosion purposes, as well as the plating thickness of the significant surfaces and the corrosion-resistance properties. (The corrosion resistance properties are described in another section.)

[Table] Nickel and chrome plating on zinc alloy substrates

* The plating thickness of multilayer plating comprised of Cu/Nib or Cu/Nid will be determined and agreed between the parties concerned.