Effect of alloying elements on the amorphous formation and corrosion resistance of electroless Ni–P based alloys

In order to verify the effect of alloying elements on the amorphous formation and corrosion resistance of electroless Ni–P based alloys, a series of alloys for the binary Ni–P, ternary Ni–Sn–P and quaternary Ni–Sn–Cu–P alloys have been prepared by chemical plating. It has been found that P is an easily formable element of the amorphous phase and adding the tin to the binary Ni–P alloys improves the formability of the amorphous phase. However, copper is a non-favorable element for the formation of the amorphous phase. The experimental fact can be understood with the formation theory of amorphous alloys by one of the authors. It has been also found that adding tin to the Ni–P deposits does not usually improve the corrosion resistance but adding copper usually improves the corrosion properties for the Ni–P and Ni–Sn–P deposits. The corrosion properties for either Ni–Sn–P or Ni–Sn–Cu–P amorphous deposits are as good as or superior to those of stainless steel.