What is pcb immersion gold process?
PCB assembly is an indispensable process for electronic products. The surface finishing of PCB refers to covering a layer of protective film on the PCB to prevent the oxidation of copper foil and improve solderability and reliability. The PCB immersion gold process is a commonly used surface finishing method. It is to immerse the PCB board in a solution containing gold salt, and form a layer of metal gold film on the PCB board through chemical or electrochemical reactions. This article will introduce the principle, characteristics and application of PCB immersion gold process.
The principle of PCB immersion gold process.
The principle of the PCB immersion gold process is to use the high potential of gold in the oxidation-reduction reaction to reduce gold ions to gold atoms and deposit them on the PCB. According to the different reaction methods, the PCB immersion gold process can be divided into chemical immersion gold and electrolytic immersion gold.
Chemical immersion gold refers to the redox reaction between gold ions and copper or nickel on the substrate by adding chemical reagents such as reducing agents and catalysts in the absence of external current to form a uniform and dense metal gold film. The advantages of chemical immersion gold are simple operation, low equipment cost, and the ability to uniformly deposit metal gold on complex-shaped PCBs. The disadvantage of chemical immersion gold is that the reaction speed is slow, the deposition thickness is difficult to control, and it is easily affected by factors such as pollutants and temperature.
Electrolytic gold immersion refers to the electrochemical reaction between gold ions and copper or nickel on the substrate through the anode and cathode in the electrolytic cell under the condition of external current to form a layer of metal gold film with controllable thickness. The advantages of electrolytic immersion gold are fast reaction speed, controllable deposition thickness, and high purity and adhesion. The disadvantages of electrolytic gold immersion are complex operation, high equipment cost, and high requirements on the surface quality of the substrate.
Features of PCB immersion gold process.
The PCB immersion gold process has the following characteristics:
Protection: Metal gold film can effectively prevent the oxidation or sulfide of copper or nickel on the base material, prolonging the service life of the PCB board.
Solderability: Metal gold film has good solderability and electrical conductivity, and can form firm and reliable solder joints with various solders.
Aesthetics: The metal gold film has luster and color, which can improve the appearance quality of the PCB board.
Compatibility: Metal gold film can be combined with various surface treatment methods, such as tin plating, silver plating, palladium plating, etc., to meet different functional and performance requirements.
Application of PCB immersion gold process.
PCB immersion gold technology is widely used in various high-end, high-precision, high-reliability electronic products, such as communication equipment, computers, medical instruments, aerospace, military industry, etc. The PCB immersion gold process can improve the electrical properties, mechanical properties and corrosion resistance of PCB boards, and is suitable for electronic products in harsh environments such as high frequency, high speed, high temperature, and high pressure. The PCB immersion gold process can also be used to make PCB boards with special functions, such as touch screens, sensors, keyboards, etc.