MATRIX EFFECT OF BOMBARDMENT-INDUCED GIBBSIAN SEGREGATION ON CU DEPLETION AT A CUXNI100-X SUBSURFACE

A dynamic Monte-Carlo program, including an improved BIGS (Bombardment -Induced Gibbsian Segregation) model was employed to study the matrix effect of BIGS and its influence on Cu depletion at the subsurface und er 1 keV Ar-ion bombardment of a Cu-Ni alloy. The calculation results show that not only at high fluences (the steady state) but also at low fluences, the Cu subsurface depletion depends on its bulk composition . This is because the atomic jump rate W-21 of Cu from the second laye r to the first layer is correlated to Cu bulk composition at any fluen ce. We also found that the product of the non-segregating species conc entration at the first layer with the segregating species concentratio n at the second layer plays a more important role than other parameter s in determining W-21 under low current conditions.