In today's society, the appearance of many cars are decorated with electroplating process, which can not only add a sense of fashion to the car lamps, but also make the car as a whole rich sense of advanced. However, as electroplating parts on cars are usually exposed to the outdoors and have to go through a variety of environmental tests, so electroplating parts on the outside of cars need very strict process and evaluation standards. General automotive lamps and lanterns can be electroplated according to the conditions of use, which are now divided into four types: Grade U. The conditions of use are strict, and the applicable examples are external parts. Grade S, the use condition is strict, the applicable example is the external parts; Grade A, the use condition is ordinary, the applicable example is the external parts; Grade B, for ease of use, for inner parts as applicable. The electroplating process and test method of chromium electroplating for decoration on A certain Type of Japanese car taillights are described in detail below.

1. Types of electroplating

The type of electroplating used for lamp decoration of A Japanese car is grade S, the use condition is strict, the applicable example is the exterior parts, the material type is plastic.

2. Plating quality

2.1 Electroplating method

Electroplating method: copper, nickel, chromium and other elements are attached to the surface of the substrate by electrolysis, so that it has a metallic luster. In addition, the nickel layer is also subdivided into several electroplating methods. The electroplating method used in this lamp is 2 nickel or 3 nickel + dispersed stress (nickel seal) and micro hole chromium. In the case of 2 nickel and 3 nickel, the thickness of semi-gloss nickel layer is not less than 1/2 of the total thickness of nickel layer.

2.2 Minimum coating thickness

Thickness measurements are made by means of a microscope or an electrolytic film thickness gauge. In addition, for chromium only, a fluorescence X-ray film thickness gauge is also available. The measuring position of coating thickness should be the minimum thickness in principle. But because of the shape of the plating coating uneven thickness of the coating can be negotiated between the parties to change the measured position. In addition to zinc alloy and aluminum alloy base material, other base material can be replaced by nickel plating copper plating. Copper thickness should ensure appearance and hot and cold circulation. The thickness of the copper layer shall be at least one time of the thickness of the nickel layer, although the base material conditions such as shape, size and forming conditions are different. The minimum nickel coating thickness and the minimum chromium coating thickness have different regulations according to the use environment.

2.3 appearance

Under indoor light, visual inspection is performed 500mm away from the test surface. The surface of the coating should be smooth and shiny, without stains, bloating, wounds, cuts, material exposure, trachoma, not smooth and other abnormal phenomena. However, it does not apply to the parts of the vehicle that cannot be seen. The limit sample shall be determined through consultation between the parties concerned. The limit shall be the extent to which the appearance defects of the vehicle are not obvious after visual inspection at an interval of 50cm in sunlight.

2.4 Corrosion resistance

Saline spray test (SST): continuous according to JISZ2371 or ASTMB117. For Class S and Class A, no flying stone test without rust is qualified. For plastic materials, no salt spray test (SST) is required.