NiP is often used in the connector industry instead of Ni as sub-layer of Au and diffusion barrier on Cu or brass. The phosphorous content influences the mechanical and magnetic properties of the layer.
Therefore not only the thickness of such a layer is important but also the composition, especially the content of phosphorous. It is possible to measure the P-content of NiP coatings on small structures such as connectors or small features on PCBs, as long as the NiP-layer is not covered. Therefore an X-ray fluorescence measurement system is the suitable instrument. As an example a small CuZnconnector coated with NiP was measured. Thickness and composition of the layer were determined on this sample – a thin half-tube – 2mm from the end.