- Mar 14, 2018 -
The principle of electrolysis cell is used to deposit a well-attached metal coating with different properties and matrix materials on the mechanical products. The plating layer is more uniform than the hot dip layer and is generally thin, ranging from a few microns to tens of microns. Through electroplating, it is possible to obtain decorative protection and various functional surface layers on mechanical products, and also to repair worn and mismachined workpieces.
In addition, there are different roles depending on various plating requirements. Examples are as follows:
1. Copper Plating: Priming, to enhance the plating layer adhesion, and corrosion resistance. (Copper is easily oxidized. After oxidation, the green is no longer conductive, so the copper plating product must do copper protection)
2. Nickel plating: use primer or appearance to improve corrosion resistance and wear resistance (in which chemical nickel is more resistant to chrome plating in modern processes). (Note that many electronic products, such as DIN heads and N-heads, are no longer nickel-backed, mainly due to the magnetic properties of nickel which can affect the passive intermodulation within the electrical properties)
3. Gold Plating: Improves conductive contact resistance and improves signal transmission. (The gold is the most stable and the most expensive.)
4. Palladium-nickel plating: Improves conductive contact resistance, improves signal transmission, and has higher wear resistance than gold.
Tin-plated lead: Improves welding ability and is quickly replaced by other alternatives (because most of the lead is now plated with bright tin and matte tin)
5. Silver Plating: Improves conductive contact resistance and improves signal transmission. (Silver has the best performance, easy to oxidize, and also conducts electricity after oxidation)
6. Electroplating is a method of plating a conductor with a layer of metal using the principle of electrolysis.
In addition to electrical conductors, electroplating can also be used on specially treated plastics.
The electroplating process is basically as follows:
Plating metal at the anode.
Material to be plated at the cathode.
The anode and cathode are connected by an electrolyte solution composed of positive ions of the plated metal.
When a direct current power source is used, the anode metal oxidizes (lose electrons), and the positive ions in the solution are reduced (electrons obtained) into atoms at the cathode and accumulate on the surface of the cathode.
After electroplating, the aesthetic appearance of the electroplated article is related to the size of the current. The smaller the current is, the more attractive the electroplated article will be; otherwise, some uneven shapes will appear.
The main uses of electroplating include the prevention of metal oxidation (such as rust) and decoration. The outer layer of many coins is also electroplated.
Wastewater from electroplating, such as spent electrolytes, is an important source of water pollution. The electroplating process has been widely used in the process of the lead frame of semiconductors and microelectronic components.
VCP: vertical continuous plating, the new machine used in the circuit board, better quality than the traditional suspension plating.
Partial silver plating:
Aluminum Plating Solution Formulation Process:
High-temperature weak base etch → cleaning → pickling → cleaning → zinc leaching → cleaning → secondary zinc leaching → cleaning → pre-copper plating → cleaning → pre-plated silver → cyanide bright silver plating → recovery washing → cleaning → silver protection → cleaning → Drying.
From the process perspective, the selected protective material must be resistant to high temperatures (around 80°C), alkali and acid resistance, and secondly, the protective material can be easily stripped after silver plating.
Commercially available protective materials include peelable rubber, strippable paint, general adhesive tape, and adhesive tape. The protective materials were tested for their acid and alkali corrosion resistance, high temperature resistance (about 80°C maximum temperature of the alkaline etching solution), and peelability.