Material surface treatment: electroplating

Material surface treatment: electroplating

1. Electroplating can coat metal film on the surface of workpiece.

Electroplating is the process of plating a thin layer of other metals or alloys on some metal surfaces by electrolysis principle. It is a process of using electrolysis to attach a metal film to the surface of metal or other materials to prevent metal oxidation (such as rust), improve wear resistance, conductivity, reflectivity and corrosion resistance (coating metal mostly uses corrosion-resistant gold). It has the function of improving beauty, etc.

II. Applicable Materials for Electroplating

Most of the coatings are single metals or alloys, such as titanium, palladium, zinc, cadmium, gold or brass, bronze, etc. There are also dispersion layers, such as nickel-silicon carbide, nickel-Graphite fluoride, etc. There are also cladding layers, such as copper-nickel-chromium layer on steel, silver-indium layer on steel, etc. In addition to iron-based cast iron, steel and stainless steel, there are non-ferrous metals, or ABS plastics, polypropylene, polysulfone and phenolic plastics. However, before electroplating, plastics must undergo special activation and sensitization treatment.

III. The Role of Different Electroplating

1. Copper plating: used as a base to improve the adhesion and corrosion resistance of electroplating. (Copper is easy to oxidize, after oxidation, copper green no longer conducts electricity, so copper-plated products must be protected by copper). Copper plating has been used for many years in PCB manufacturing industry. Copper plating solution for PCB is acidic solution with high acid and low copper content. It has excellent dispersing ability and luster after deep plating.

2. Nickel plating: Nickel plating is widely used as a protective decorative coating. It can protect the base material from corrosion or play a bright decorative role on the surface of steel, zinc die-casting, aluminum alloy and copper alloy. It is also often used as the intermediate coating of other coatings, on which a thin layer of chromium or a layer of imitation gold is plated, which has better corrosion resistance and better appearance.

3. Gold plating: Improving conductive contact impedance and enhancing signal transmission (gold is the most stable and expensive), is also a very common decoration process.

4. Palladium-nickel plating: improve the conductive contact impedance, enhance signal transmission, wear resistance is higher than gold.

5. Tin-plated lead: improve welding ability and be replaced by other substitutes (because most of the lead content is now changed to bright tin and fog tin).

6. Silver plating: Improving conductive contact impedance and enhancing signal transmission. (Silver has the best properties, is easy to oxidize and conducts electricity after oxidation.)