CC BY
18LMI-I-6
Reverse deposition of oxides under nanosecond laser ablation of metals: physical mechanisms and applications
V.P. Veiko1, J.J. Karlagina1, A.A. Samokhvalov1, D.S. Polyakov1, I.B. Gornushkin2
1 - ITMO University, Saint-Petersburg, Russia 2 - BAM Federal Institute for Materials Research and Testing, Berlin, Germany
vadim. veiko@mail.ru
Processes of laser induced oxidation of metals usually are mainly studied in the framework of heterogeneous chemical reactions on the irradiated surface, which lead to the formation of dense oxide films on it. Such technology has many applications like color-laser marking technology [1] and laser recording on thin metal films for creation of diffractive optical elements [2]. At the conditions of strong laser ablation another oxidation mechanism becomes possible: evaporated atoms react with oxygen in a surrounding atmosphere and the products of such reaction can be redeposited back onto the substrate. The chemical and phase composition of such deposited layer, its density, morphology and structure depend on the conditions of laser ablation. It allows to control the main properties of such coating that is important for some potential application (for example in biomedicine).
In our report we present study of the processes of redeposition of oxides structure under the conditions of multipulse nanosecond laser ablation of titanium (Grade 2) in air atmosphere at normal conditions. Typical picture of redeposited structures and emission spectrum of laser plasma are shown on the Fig. 1
Fig. 1 - TEM, SEM pictures of nano-porous layer formed by laser ablation of titanium and optical emission spectrum of laser plasma.
One can see that treated surface is covered by nano-porous layer which consist mainly from titanium oxides. Our experiments shows that titanium-implants with such deposited oxide layer have increased biocompatibility [3].
Modelling of chemical reaction in laser-induced plasma coupled with experimental methods of plasma optical emission spectroscopy allows us to determine the types of main chemical reactions in laser plasma as well as it influences on the plume dynamics and vapor condensation kinetics. As the result we propose the general physical picture of reverse deposition of oxides structure under the condition of strong nanosecond laser ablation. The formation of the titanium oxide precipitate is explained not only by collisions in the plasma, but also by the chemical interaction of titanium and oxygen, which leads to the formation of a low pressure area near the substrate and additionally stimulates the reverse deposition of oxides. The main features of this picture, as we expect, are valid not only for titanium but for other metals and semiconductors.
The study was supported by the Russian Science Foundation (project N° 20-62-46045).
[1] Odintsova G., Andreeva Y., Salminen A., Roozbahani H., Van Cuong L., Yatsuk R., Golubeva V., Romanov V., Veiko V. Investigation of production related impact on the optical properties of color laser marking/Journal of Materials Processing Technology, 2019, Vol. 274, pp. 116263
[2] Veiko V.P., Zakoldaev R.A., Shakhno E.A., Sinev D.A., Nguyen Z.K., Baranov A.V., Bogdanov K.V., Gedvilas M., Raciukaitis G., Vishnevskaya L.V., Degtyareva E.N. Thermochemical writing with high spatial resolution on Ti films utilising picosecond laser//Optical Materials Express, 2019, Vol. 9, No. 6, pp. 2729-2737
[3] Veiko V.P., Karlagina Y.Y., Itina T.E., Kuznetsova D.S., Elagin V.V., Zagaynova E.V., Chernenko G., Egorova E.E., Zernitskaia C., Manokhin S.S., Tokmacheva-Kolobova A., Odintsova G.V. Laser-assisted fabrication and in vitro verification of functionalized surface for cells biointegration//Optics and laser technology, 2021, Vol. 138, pp. 10687.
