The surface treatment technology of pcb board includes oxidation resistance, tin spraying, lead-free tin spraying, gold precipitation, tin precipitation, silver precipitation, hard gold plating, gold plating of all the plate, gold finger, nickel palladium gold OSP, etc.
Among them, the gold-deposited pcb board and the gold plated pcb board are often used in PCB circuit boards. Many engineers can not correctly distinguish the difference between the two. So today's edition summarizes the difference between the two.
What we call gold plated pcb board is generally referred to as "electroplated gold", "electroplated nickel-gold plate", "electrolytic gold", "electroplated nickel-gold plate". There is a distinction between soft gold and hard gold (generally hard gold is used for golden fingers). The principle is to dissolve nickel and gold (commonly known as gold salt) in chemical solution, immerse circuit board in plating cylinder and turn on current to form nickel-gold coating on the copper foil surface of circuit board. Electronickel gold is widely used in electronic products because of its high hardness, wear resistance and difficult oxidation.
Deposition of gold is using a method of chemical oxidation-reduction reaction to produce a layer of gold deposit which is generally having a thicker thickness. It is a method of deposition of chemical nickel-gold deposit, which can achieve a thicker layer of gold.
1. Generally, the thickness of gold deposit is much thicker than that of gold plating. The gold deposition will be more yellow than that of gold plating. The customers are more satisfied with gold deposition from the surface. The crystal structure formed by the two is different.
2. Because of the different crystal structure formed by gold deposition and gold plating, gold deposition is easier to weld than gold plating, which will not cause bad welding and cause customer complaints. At the same time, because the gold deposit is softer than the gold plating, the gold finger plate is generally chosen to be gold plated, and the hard gold has the characteristic of the wear-resistant.
3. There is only nickel and gold on the pad of the gold deposit plate. The signal transmission in the skin effect is that the copper layer will not affect the signal.
4. Compared with gold plating, gold deposit has a denser crystal structure and is not easy to oxidize.
5. As the wiring becomes more and more dense, the widths and spacing have reached 3-4 MIL. Gold plating is prone to cause the short circuit of the golden silk. Only nickel and gold are on the pad of the sunken gold plate, so the short circuit of the gold wire will not be produced.
6. Only the pad has nickel and gold on the sunken gold plate, so the combination of resistance welding and copper layer on the circuit is stronger. The spacing will not be affected when the project is compensated.
7. Generally used for relatively high requirements of the board, it has the good flatness, which is generally using gold deposit which generally will not appear the black mat phenomenon after assembly. The smoothness and service life of sunken gold sheet are as good as those of gold plated sheet.
8. Gold is very expensive on the market nowadays. In order to save costs, many manufacturers are reluctant to produce gold plated pcb board, but only make nickel-gold sunken plate on the welding pad, which is really cheap.