The current state of laser technologies in the field of functional coatings

Abstract

Two main directions in the field of laser radiation application for functional coatings are considered - the application of coatings using purely laser study and the combination of laser and other technologies. The most popular technological lasers used in both directions are identified: gas molecular lasers, diode, fiber, and solid-state lasers. Methods of hardening heat treatment of parts using a laser beam both with and without melting of the material are considered. A method of introducing alloying components of metallic and non-metallic nature into the substrate material using laser technologies is presented. The methods of laser surfacing are given, where the surfacing material is fed into the zone of exposure to laser radiation both in the form of a powder mixture and in the form of a filler wire. Powder mixture is most commonly used as surfacing material, wire is less often used. Technologies of laser-assisted evaporation used in the creation of three-dimensional objects are considered. Hybrid technologies of coating deposition are presented - laser surfacing using a plasma arc and high-frequency heating. It was found out that two types of plasmatrons are used in laser-plasma surfacing - direct and indirect types of action. In addition to hybrid laser surfacing, the method of hybrid laser-assisted evaporation is considered - plasma sputtering, or LAAPS, accompanied by laser heating and allowing to obtain coatings with increased adhesion strength to the substrate surface. The main advantages (the ability to adjust the thickness of the deposited coating layers, reduction of the thermal impact zone) and disadvantages (occurrence of cold microcracks on the surface, formation of pores in the coating) in the application of coatings using laser radiation are considered. The prospects for the development of laser and laser-plasma technologies in the field of functional coatings are analyzed on the example of practical application. The development of these technologies in future is largely due to the elimination of their shortcomings, increasing the efficiency of interaction between laser and plasma technologies.