It is known~(1-4) that films of electroless alloys Ni-W-P have been obtained by introduction of sodium tungstate into citrate-hypophosphite solution for electroless deposition Ni-P alloys. Ni-W-P alloys can contain 4-21 at. percent P and 1-8 at. percent W depending on the solution composition (Na_2WO_4, nickel salt, sodium citrate concentration, and NH_4~+ ion presence) and pH. It was reported that Ni-W-P films have the perfect properties, which significantly differ from the analogous for Ni-P alloys. In partic-ular, it's worth noting that Ni-W-P alloys' crystallinity depend not only on phosphorus but also on tungsten concentration. Apportionment of the phosphide phase (Ni_3P) was inhibited in tungsten presence. It was supposed that tungsten was included in alloys either eutectically1'4 or in composition of solid-state solution. ~(2,3)In previous publications ~(5,6) we considered the special features of Ni-W-P deposition on the surface of gallium arsenide monocrystals and presented information about the factors affecting the chemical composition and phase constitution of the alloys.
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