Many DIY players will find that the PCB colors used in a variety of board and card products in the market are dazzling. The more common PCB colors are black, green, blue, yellow, purple, red and brown. Some manufacturers have ingeniously developed different colors of PCB such as white and pink.

     In the traditional impression, black PCB seems to be positioned at high -end, while red, yellow, etc. are dedicated to low -end. Is this like this?

     The PCB copper layer without welding paint is exposed to the air easily oxidized

     We know that the PCB on both sides is a copper layer. In the production of PCB, the copper layer will obtain a smooth and non -protected surface in the end. Although the chemical properties of copper are not as lively as aluminum, iron, magnesium, etc., under the conditions of water, pure copper and oxygen contact are easily oxidized; because oxygen and water vapor in the air, the surface of pure copper is in contact with the air after contacting the air. Oxidation reactions will soon occur. Because the thickness of the copper layer in PCB is thin, the oxidized copper will become a bad conductor of electricity, which will greatly damage the electrical performance of the entire PCB.

     In order to prevent copper oxidation and to separate the welding part of the PCB during welding, the engineers invented a special coating in order to protect the PCB surface layer. This coating can easily paint on the PCB surface, forming a protective layer with a certain thickness, and blocking the contact of copper and air. This layer of coating is called a welded layer, and the material used is welded paint.

     Since it is called lacquer, there must be different colors. That's right, the original welded paint can be made into colorless and transparent, but in order to repair and manufacture convenience, PCB often needs to print small text on the board. Transparent welded paint can only show the PCB background, so that the appearance is not good enough whether it is manufacturing, maintenance or sales. Therefore, engineers added a variety of colors to the welded paint, and finally formed a black or red and blue PCB.