What Is The Difference Between Nickel-plated Copper And Tin-plated Copper?

All varieties of coatings share the common benefits of providing anti-corrosion properties (enhancing anti-oxidation capabilities) and serving decorative purposes.

After electroplating, nickel-plated copper busbars exhibit good chemical stability in atmospheric conditions and alkaline solutions, resisting discoloration. However, it does oxidize when exposed to temperatures above 600 degrees Celsius. This material is characterized by high hardness and ease of polishing. A notable drawback is its porosity. The surface of nickel-plated copper boasts a bright appearance and a smooth tactile sensation. It also demonstrates relatively strong adhesion and wear resistance.

Tin-plated copper busbars are distinguished by their high chemical stability, being virtually insoluble in dilute sulfuric acid, nitric acid, and hydrochloric acid solutions. It offers excellent welding performance, and the tin plating layer provides effective protection against electromagnetic interference. Aesthetically, tin-plated surfaces appear white but are less visually appealing. Additionally, when touched by hand, a layer of dark gray tin foam may form on the surface.

The choice between nickel plating and tin plating depends on the specific application requirements:

1. For appearance-critical components, nickel plating is generally preferred due to its smooth, attractive finish and resistance to discoloration even after high-temperature testing.
2. When strong electrical conductivity is essential, copper bars should be tin-plated.
3. For internal components, such as EMI shields on PCB boards, tin plating (barrel plating) is typically employed. In some cases, a dual-layer approach of nickel plating followed by tin plating is used for the base layer.

Conductivity Comparison Tests

Figure 1

The conductivity of the copper bar before tin plating is 98.6% IACS.

Figure 2

The conductivity of the copper bar after tin plating exceeds 98.6% IACS, showing a slight increase compared to before tin plating (with the median knob also adjustable).

Figure 3

The conductivity of the copper bar before nickel plating is 98.6% IACS.

Figure 4

The conductivity of the copper bar after nickel plating drops to 75.8% IACS, which is 22.8% IACS lower than that of the tin-plated copper bar.