The ZESTRON Coating Layer Test, which is used to detect any coating defects on electronic assemblies, can also check the wetting capability of components before soldering.
When a component’s contact point is immersed in the test liquid, a non-destructive black color reaction occurs to indicate wetting ability. In the presence of a reaction, the components have clean and good quality metallization and can be used in production. In the absence of a color reaction, it is likely that an intermetallic phase has grown through to the surface – this is particularly prevalent with chemical tin – making it difficult to form a connection with the solder. This can lead to weak solder joints and ultimate field failure of the electronic assembly.
This non-destructive test can check the solderability quickly, cost-effectively, and can be used during production for random sample inspection.