2. Mainly include zinc plating, copper plating, nickel plating, chromium plating, iron plating, tin plating, lead plating and precious metal plating (gold, silver, palladium, rhodium, platinum, etc.). ), electroplating of various alloys and so on. Silver-copper alloy electroplating is mainly used for electric contact coating, with fine crystal, small brittleness and better wear resistance than pure silver.
3. Nickel plating on large plates is not easy to be uniform, with thick and bright periphery and thin and dark middle. The concept of "dispersion ability" is used to explain this phenomenon in electroplating. In order to make electroplating as uniform as possible, in addition to strengthening stirring, using displacer and increasing electrode spacing, auxiliary anode is mainly used.
There are many ways to recycle gold. Here is one: under ventilated conditions, adjust the pH value to about 1 with hydrochloric acid, heat to 70-80℃, add zinc powder while stirring until the solution is transparent and yellowish, and there is gold powder precipitation, filter, and cook the gold powder with hydrochloric acid first, then with nitric acid, then with pure water for several times, and dry.
5. After gold plating, clean it thoroughly with pure water in time and dry it in time, which generally won't produce water stains, let alone oil stains.
6. Electroplating quality control should pay attention to the following three points: (1). Establish and effectively implement modern quality management system and rules and regulations, clarify responsibilities and check at all levels; (2) Analyze and adjust the composition of the solution in time to ensure the normal solution; (3) Operate in strict accordance with the process regulations.
7. The kovar material, namely the kovar alloy, consists of Ni29%, Co 17% and Fe54%, and is used for sealing electronic components and glass-ceramics devices.
8. Electroless nickel plating is one of the most widely used electroless plating processes, and sodium hypophosphite is often used as reducing agent. The obtained coating is actually a nickel-phosphorus alloy, which is not only used for metallization of nonmetallic electroplating, but also used for functional coatings, such as corrosion-resistant and wear-resistant coatings. Electroless silver plating used to make mirrors and thermos bottles, but now it is mostly used for parts with complex shapes and high reflectivity. The coating is very thin, the stability of the plating solution is poor, and it can only be used once, so the cost is high. Electroless gold plating layer has good chemical stability, corrosion resistance, electrical conductivity, wear resistance and weldability. Commonly used for coating electrical contacts of electronic components, the coating is thin, and the current process is difficult to exceed 1 micron.
9. Pulse electroplating is electroplating with a certain waveform of pulse current, which makes the deposition of metal ions pulse, which can not only improve the electroplating speed, but also improve the coating quality.