Intermetallic Layer

A thin layer in the solder joint, found at the interface between solder and the joining part. In the soldering process, the liquid solder interacts with the solid base metal, and they both combine at the interface into what is labeled the intermetallic compound. This layer is also sometimes called the diffusion zone. In soft soldering, it has a thickness of approximately 0, 5 µm. See also diffusion zone.