PSI - Issue 40

S.A. Filin et al. / Procedia Structural Integrity 40 (2022) 153–161 S. A. Filin at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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action and, as a result, (Aadmc). Surface wetting depends on the composition of the detergent medium, surface tension, and the material to be cleaned. The detergenting action consists in the removal of liquid and solid contaminations from the surface and translation them into the detergent medium in the form of a solution or dispersion. The main phenomena, that determine the detergenting effect, are the processes of physicochemical adsorption (Aa), wetting (Аw), emulsification (Аe), dispersion (Аd), foaming (Аf), micelle formation (Аmf) and stabilization (Аs). Physicochemical adsorption of surfactants reduces the adhesion strength of contamination and metal, as well as the resistance of contamination to mechanical stress, contributes to increase in dispersion on the surface of the optics. This ultimately speeds up the process. When the detergent medium comes into contact with the surface to be treated or contamination, a boundary layer appears on the surface of the solid. Its molecules are not in equilibrium with the liquid medium and have an excess of free energy. It determines adsorption activity (the ability to adsorb molecules of other substances on itself, lowering its free energy until the intermolecular forces are completely equalized). The excess free energy determines the surface energy or tension. However, the surfactant concentration in the solution has a significant effect on (Aadmc): its excess (> 3 wt %) can lead, due to a change in the solubility parameter (δ) of the solvent, to significant contamination of the solvent and the surface to be cleaned. Therefore, due to factors affecting (Aadmc) (moderate, close to room temperature, the minimum concentration of the emulsifier with the selection of the solubility parameter (δ) of the washing medium closest to the solubility parameter of the contamination present on the surface to be cleaned), when cleaning mirrors, it is advisable to use a detergent media, based on a composition of non-aqueous solvents without emulsifier or with its lowest possible content. To intensify the cleaning process, it is advisable to use the immersion of the mirror in the detergent medium with its activation by submerged jets or the displacement of the object in the detergent medium, or bringing the detergent medium to the surface of the element. That is, when cleaning of metal optics, it is necessary to rationally use all of the factors, influencing the cleaning work (Аc) - work (Aadmc), depending on the composition of the detergenting and cleaning medium, and work (Amidm) associated with the mechanical effect of the detergent medium, with the predominant use (Aadmc). In this case, the properties of the mirrors must be taken into account. The study of the proposed model of the physicochemical process of cleaning mirrors was carried out simultaneously with the study of optical elements made from materials of high-energy laser systems. 6. Conclusion Analysis of the main cleaning and detergenting processes shows their high energy intensity. Direct energy costs for cleaning are ≥ 2.5% of the consumed energy, and the time consumption for a number of industries are up to 10% of the total time required for the manufacture of a mirror, which indicates great opportunities for improving cleaning processes and reducing their labor and energy consumption. The verification of the model of the physicochemical process of removing contaminations from the surface of the mirrors, proposed by the authors, was implemented on an installation, operating in a semi-automatic mode in a closed technological cycle (at present, it has exhausted its resource), and on its laboratory version, as well as from the assessment of the optical characteristics of the mirrors and its durability during operation. Additional information on the nature of the physicochemical processes during cleaning and their effect on the optical parameters of the mirrors is expected to be obtained from the kinetic analysis of these processes on a fully automated installation (with an automated system for monitoring the chemical purity of an optical surface during the cleaning process, including its input / output control), currently being developed. References Shmakov, V.A., 2004. Power optics, Nauka, Moscow. (In Russ.). Perlin, E.Yu., Vartanyan, T.A., Fedorov, A.V., 2008. Solid state physics. Optics of semiconductors, dielectrics, metals, St. Petersburg State University ITMO, St. Petersburg. (In Russ.) Rogalin, V.E., Kaplunov I.A., 2013. Optical properties of metal mirrors for CO 2 lasers, News of Sochi State University 4-2(28), 120-127. (In Russ.)