The Difference Between Bright Tin and Foggy Tin Plating on the Iron Case Terminal of Connector
Features of connector tin fog: the appearance is foggy, the crystal is rough, easy to leave fingerprints, the general thickness is 5um, 8um, or even higher, and the plating thickness varies according to its use. Fog tin is better than bright tin in solder ability and whisker resistance, but it is afraid of scratches and fingerprints.
Features of connector bright tin: bright appearance, good-looking, smooth, fine crystal, not easy to leave fingerprints, with a general thickness of more than 3um. General pure functional parts will choose fog tin, need to solder but belong to the appearance of parts will choose bright tin.
The difference between the two:
1. Polish is used for connector bright tin, and there are more organics in the metal, so the weld ability is poor; no polish is used for fog tin, and there are less organics in the metal, so the weld ability is good.
2. The former is mainly alkaline tin plating, the latter is mainly acid bright tin plating. However, they are all pure tin coatings with poor performance at low temperature. In actual use, it is found that the high temperature resistance of the tin mist is better than that of the bright tin. Sometimes the bright tin will melt when passing through the tin furnace, but the tin mist is better.
3. The electroplating time of terminal fog tin will be longer, the fog tin will be more fine, the welding performance will be better, and the temperature resistance will be higher.
4. In appearance, the bright tin of connector iron shell is more beautiful than that of tin mist; the wetted tin mist is better, and the bright tin on the surface after SMT (baking) test is easier to turn yellow than that of tin mist, while the surface of tin mist is easier to be attached with dirt and inclusion if it is not carefully received due to structural factors.
5. Terminal fog tin is mainly used for its reliability after welding, which is less likely to produce capillary phenomenon compared with bright tin.
6. Compared with bright tin, terminal tin mist is more effective in inhibiting the growth of tin whisker; in terms of electroplating cost, the cost of tin mist is slightly higher.
7. In the view of the use end, bright tin is more beautiful; fog tin is more stable.