Heイオンビーム加工による表面粗さの改善

抄録

Ion-beam machining has been investigated for its effect in decreasing surface roughness, and it has already been reported that low surface roughness can be obtained by low-energy argon ion-beam machining. In this study, low-mass helium ions were used to decrease the roughness of a mirror finished SKD 1 (high chromium-high carbon steel) surface. The results obtained were as follows: (1) A greater decrease in surface roughness was obtained with helium ion-beam machining than with low-energy argon ion-beam machining. (2) There is an optimum machining condition for decreasing the surface roughness, and the lowest surface roughness (6nm R_max) obtained at a beam energy of 2keV, a beam current density of 4A/m² and a beam angle of 70°. (3) The decrease in surface roughness is obtained within the oxide layer (about 0.03μm). (4) The mechanism of the decrease in the surface roughness is discussed in terms of the knock-on cascade model.