METALLURGICAL STUDY ON HARDNESS DISTRIBUTION BY HIGH-ENERGY ION-IMPLANTATION TAKING NOTICE OF SOLID-SOLUBILITY

Fundamental experiments taking notice of the solid-solubility of the i mplanted ions in a substrate were conducted with the aim of elucidatin g the mechanism causing a change in hardness distribution, because the solid-solubility is considered to have a strong influence on the beha vior of the implanted ions within the substrate. Ion implantation of c arbon (C) ions into substrates of two different materials, i.e., nicke l (Ni) and copper (Cu), was attempted with an acceleration energy of 3 MeV and with dose levels between 1 x 10(16) ions/cm2 and 5 x 10(17) i ons/cm2. C ions were used because the solid-solubility of C in Cu is g reatly different from that in Ni. In Ni, which has a limited terminal solid-solubility for C, a Gaussian-like hardness distribution was obta ined, whereas in Cu, which has no solubility for C, a uniform hardness distribution was achieved over the depth direction. Those results sug gest that the solid-solubility as a metallurgical parameter has a stro ng influence on the hardness distribution which results from ion impla ntation.