AMORPHIZATION OF NICKEL AND NI-P ALLOYS BY ION-IMPLANTATION

Room temperature ion implantation of 40 keV phosphorus ions into crystalline (f.c.c.) nickel resulted in the formation of h.c.p. nickel at low doses followed by amorphization, and at high doses the formation of b.c.t. Ni3P. These observations can be understood in terms of a model involving surface sputtering and radiation-enhanced diffusion. Ion implantation of 40 keV argon ions into crystalline Ni79.1P20.9 at room temperature resulted in partial amorphization at 1 d.p.a. (displacement per atom) and complete amorphization at 10 d.p.a. The amorphous phase formed by gradual diffusion of phosphorus in a manner consistent with amorphization by diffusion couples and solid state mechanical alloying. A damage-composition map analogous to an equilibrium phase diagram is constructed in order to explain these experimental observations.