PConcept of wetting for CBA inserts welding

1, the physical basis of welding "wetting", wetting is also called "infiltration". Wetting refers to the spread of the liquid on the contact surface with the solid, fully spread contact, this phenomenon is called wetting. The process of tin welding is to melt, flow and moisten the lead-tin solder on the welding surface by heating, so that the lead and tin atoms can penetrate into the surface of the copper base material (wire, welding pad) and form a cu6-sn5 brittle alloy layer on the contact surface.

2. In the welding process, the included Angle formed by the contact between the solder and the base material is called the wetting Angle. When the wetting Angle is less than 90 degrees, the solder and the base material are not wetted and cannot form a good welding spot. When the wetting Angle is greater than 90 degrees, the solder and parent material wetting, can form a good solder. By observing the wetting Angle of the solder joint, the quality of the solder joint can be judged.

3, if the welding surface cut off the wetting of dirt or oxidation layer, can not produce two kinds of metal materials alloy layer, or the temperature is not high enough to make the solder did not fully melt, can not make the solder wetting.

Angle of wetting and wetting

Examples of non-wetting

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