Electrodeposition of high-tungsten W-Ni-Cu alloys. Impact of copper on deposition process and coating structure

The deposits are metallic, uniform, shiny and highly adhesive to various substrates. The layers colour, depending on copper percentage, can vary from dark silvery to bright silver-orange. Also, various mechanical properties of the deposits can be obtained by properly adjusting bath composition and therefore layer stoichiometry. The internal structure of the deposits was investigated and it was found that the size of structurally organized regions was circa 3-5 nm. The obtained material consists of two phases: a) nanocrystaline of a structure similar to cupronickel with decreased percentage of W and b) fully amorphous phase/matrix containing higher, than the mean value, percentage of W. The galvanic W-Ni-Cu layers did not exhibit preferred orientation in the [111] direction which is typical for the binary tungsten - iron-group-metal electrodeposited alloys.