Detection by sputtering of deformed areas hidden under a surface. (April 2017)

• Record Type: Journal Article
• Authors: Tolpin, K.A.; Minnebaev, K.F.; Yurasova, V.E.
• Is Part Of: Vacuum. Volume 138(2017)
• Page Start: 139
• Page End: 145
• Publication Date: 2017-04
• Subjects: Sputtering -- Binary alloys -- Deformation -- Molecular-dynamic simulation; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2016.11.002
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: A sensitive method of visualization by sputtering of deformed areas buried under a surface is developed. The effect of varying the lattice constant and binding-energy of surface atoms of binary disordered alloys on the sputtering of areas deformed by a concentrated load was examined using molecular dynamics. The calculation was carried out for Cu87 Sn13, Ni97 Fe3 and Fe97 Ni3 alloys, which are used for manufacturing of coins and items with marking signs. Experimentally and by MD simulations of energy and angular distributions of sputtered particles, we have shown that the best conditions for detection of deformed areas, buried under a surface, occur in the case of irradiation by inert gas ions of sufficiently large mass (Ar +, Kr + ) with energy of 7–10 keV, when the sputtering yield is close to its maximum value. We suggest using an inclined ion beam, near the maximum of the angular dependence of the sputtering coefficient. This leads to reduction of the time necessary for ion irradiation, and to an increase in clarity of the obtained image due to a cumulative effect in the narrow near-surface layers of the target. Using the recommended parameters of sputtering has allowed us to reveal a destroyed image on a bronze coin and images of completely ground off marking numbers on steel objects. Highlights: Influence of lattice constant variation at deformation on sputtering was calculated. Cu-Sn, Ni-Fe alloy sputtering was studied experimentally and by MD simulation. Deformation reduces lattice constant and leads to a higher sputtering of alloys. The greatest sputtering after deformation occurs at oblique ion incidence. Optimum parameters of sputtering for visualization of deformation are suggested.