Tver State University, Tver, Russia:

I. A. Kaplunov, Professor, e-mail: Ivan.Kaplunov@tversu.ru

“National center of laser systems and complexes” JSC, Moscow, Russia:
V. E. Rogalin, Head of a Sector

Plekhanov National Academy of Economics, Moscow, Russia:
S. A. Filin, Assistant Professor

Cleaning and preparation of metal surfaces is one of the main stages of technological process. These operations ensure high resource of final products for many areas of science, technology and industry. Problems of surface pollution arise in the process of exploitation of powerful infrared gas lasers, which “deaf” resonator mirrors are often made of copper, having high reflection coefficient in IR-area. Using two-beam infrared spectrophotometer “Hitachi-225” with specular reflection prefix IRR-3, there were measured reflection coefficients of freshly high polished copper surface, aged in the air at the laboratory space. For example, coefficient of reflection of pure surface of copper mirror on a wave length of λ = 10.6 microns can reach the size R = 0.990.002. Using the laser, copper mirror degrades at the expense of interaction with radiation of laser and chemical contact with active environment. Reflection coefficient can be decreased to the size of R = 0.96, and lesser, i. e. radiation losses on a mirror are increased with 0.01 to 0.04 (or approximately by 4 times and over). Application of contactless methods of surface cleaning allows to carry out partial restoration of reflection coefficient size, and, in addition, use of effect of laser cleaning — for improvement of quality of mirrors in comparison with freshly polished mirror (R = 0.985). This offered method can be also used for cleaning of rather expensive products, made of non-ferrous metals, with polished surface or difficult configuration (with internal cavities). These products can be damaged or exclude the possibility of efficient purification at its other ways.

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