The oxidation of PCB circuit board is due to the oxidation of PCB surface from secondary copper to solder proof printing,  
Since the copper surface of PCB is easy to oxidize in general environment, it can not be coated with tin, so it will be protected on the copper surface coated with tin. The protection methods include tin spraying, Huajin, silver chemical and organic welding machine. Each method has its advantages and disadvantages, which is unified into surface treatment. Before the emergence of PCB, the interconnection between electronic components depended on the direct connection of wires to form a complete circuit. At present, circuit breadboard only exists as an effective experimental tool, and printed PCB has become an absolute dominant position in the electronic industry. Usually, the color of PCB is green or brown, which is the color of resistance welding. It is an insulating protective layer, which can protect the copper wire and prevent the parts from being welded to the wrong place. A layer of screen printing surface will also be printed on the solder resist layer. Dongguan Yushi circuit board Co., Ltd. mainly produces printed circuit boards, circuit boards and flexible boards, electroless nickel plated gold. It is widely used in products, and is widely used in high-tech fields such as communication equipment, computers, industrial control, power electronics, medical devices, security, electronics, aerospace and so on. In addition, the company has imported professional equipment and testing equipment, as well as advanced printed circuit board manufacturing technology and high-quality technical management personnel. In strict accordance with the management norms of modern enterprise system, the company has established a unique scientific research system and long-term scientific planning. 6S management system shall be strictly adopted in daily production.