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In the PCB surface treatment, there is a process that is widely used, called Immersion Gold. The purpose of the Immersion Gold process is to accumulate a nickel-gold coating with stable color, good brightness, flat coating, and excellent solderability on the surface of the PCB printed circuit.
1. The role of immersion gold technology
The copper on the circuit board is mainly red copper. The copper solder joints are easily oxidized in the air. This will cause conductivity, which is poor tin eating or poor contact, which reduces the performance of the circuit board. Then you need to look at the copper solder joints. Immersion gold is to plate gold on it. Gold can effectively isolate the copper metal and air to prevent oxidation. Therefore, gold is a treatment method for surface anti-oxidation. It is a chemical reaction to cover the surface of copper with a layer of gold. Also called Huajin.
2. Immersion gold can improve the appearance of PCB board
The advantages of the immersion gold process are that the color accumulation on the surface when printing the circuit is very stable, the brightness is very good, the plating layer is very smooth, and the solderability is very good. Immersion gold generally has a thickness of 1-3 Uinch, so the thickness of the gold produced by the surface treatment method of sinking gold is generally thicker, so the surface treatment method of sinking gold is widely used in circuit boards such as key boards and gold finger boards. As gold has strong conductivity, good oxidation resistance and long service life.
circuit board
3. The advantages of choosing the circuit board of the immersion gold board
1. Immersion gold plates are bright in color, good in color and good-looking, which improves the attractiveness of customers.
2. The crystal structure formed by immersion gold is easier to weld than other surface treatments, and has better performance and quality assurance.
3. Because the immersion gold board only has nickel and gold on the pad, it will not affect the signal, because the signal transmission in the skin effect is on the copper layer.
4. The metal properties of gold are relatively stable, the crystal structure is denser, and oxidation reactions are not prone to occur.
5. As the immersion gold board only has nickel and gold on the pad, the solder mask on the circuit and the copper layer are more solid, and it is not easy to form a micro short circuit.
6. The project will not affect the distance when making compensation, which is convenient for work.
7. The stress of the immersion gold plate is easier to control, and the experience in use is better.
4. The difference between gold and gold fingers
Golden fingers are more straightforward. They are brass contacts or conductors. In detail, because gold is highly resistant to oxidation and has strong conductivity, the parts connected to the memory slot on the memory stick are plated with gold, and then all signals are transmitted through the gold fingers. Since the gold finger is composed of a lot of yellow conductive contacts, its surface is gold-plated and the conductive contacts are arranged like fingers, hence the name. In layman's terms, the gold finger is the connecting part between the memory stick and the memory slot, and all signals are transmitted through the gold finger. The gold finger consists of many golden conductive contacts. The gold finger is actually coated with a layer of gold on the copper clad board through a special process.
Due to the high price of gold, tin plating is used for most of the current memory. Tin materials have been widely used since the 1990s. At present, the "golden fingers" of motherboards, memory, and graphics cards are almost all tin-plated. Materials, as long as part of the high-performance server/workstation accessory contact points will continue to use gold-plated methods, the price is naturally high.
So, the simple distinction is that heavy gold is a kind of surface treatment circuit board process, and gold finger is a component with signal connection and conduction on the circuit board. In practice in the PCB market, gold fingers may not actually look like gold.
