Adhesion of electrodeposited nanocrystalline Ni-W coatings on Cu

A study was performed on the adhesion of nanocrystalline Ni-W alloy coatings, on copper, with the help of a scratch testing apparatus. The nanocrystalline Ni-W coatings were electrodeposited on copper substrates. The tungsten content in the Ni-W alloy coating was found to be 42 wt-% (19 at.-%). The results obtained from the scratch experiments showed that the nanocrystalline Ni-W coatings on copper suffer tensile failure and minor delamination. The mean cohesive and adhesive critical loads were found to be in the range of 19-85 N and 34-102 N, respectively and to increase with increasing thickness of the coatings.