advice of the day PCB copper is used primarily for connecting components on the substrate. Traditionally, copper as a material for forming a pattern of electrical connectivity runway, when copper is exposed without proper coating, and is used for a long time they air, is slightly dimmed by copper oxidation. He will be corroded and thus loses its weldability. Because of this problem, several techniques used to protect the traces, through holes and printed through holes (PTH). One method is with an organic coating, the oxide layer and plating, many manufacturers used coated long ago. PCB organic coating is not so simple in its application is recommended for long-term use by the ability of the control process manufacturer of starch composition and the curing cycles. It can also be unpredictable discrepancy weldability. But with the use of lead, it is widely used on consumer credit to buy PCB.

oxide layer can protect the circuit from corrosion, but it fails to preserve the solderability of PCBs. The most common method for long PCB manufacturers is a metal-coating process was a common practice to ensure the solderability and protect the circuit from corrosion before the application of lead-free era. It has been an important factor and plays an important role in the production of printed circuits on both sides and multi-layer (PTH) boards in the past. In particular, the coating of a metal welded to protect the slopes common practice to use weldable copper traces. In addition, the connectors with spring contacts mating with connector has a designed according to printed circuit boards used for the connection of modules in electronic equipment. These electrical contacts should have a high degree of wear resistance and low contact resistance. This will allow for precious metals on these contacts and the metal is most commonly used gold. Other metals are to follow to cover traces of tin, nickel, and in some cases, copper plating, to implement some of the regions used.


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