Application of Laser Thermocycling to Improve the Quality of Plasma Wear-Resistant Coatings

Abstract

The problem of the article is designed to reveal the proposed, developed and researched new method of improving the adhesion strength of plasma wear-resistant coatings on the outer surfaces of weapons made of high-alloy, heat-resistant steels, using additional cyclic (3-4) times their heating by laser radiation to temperatures of 0.6 – 0.8Tpl for a few milliseconds. The purpose of increasing the resource of use and the quality of the appearance of the weapon by applying wear-resistant coatings with increased adhesion strength to the base using plasma gas-thermal spraying followed by laser thermal cycling. Determination of the main factors and parameters of the process of laser thermocycling of plasma coatings, their interrelationships, development of an algorithm for determining the conditions of laser thermocycling, establishment of the rational range of their values by mathematical modeling and experimental research. The results of mathematical modeling of laser cyclic heating of plasma coatings of HTN of different thicknesses are presented, which allows determining the irradiation parameters that ensure their heating to temperatures at the "coating-substrate" boundary ≤1000ºС, on the surface - to Т< Тpl, at maximum cooling rates. It has been proven that laser thermocycling provides an increase in the adhesion strength of coatings to the base from 14–18 to 90–110 MPa, a decrease in porosity from 10–12% to 7–8%, which is due to the redistribution of alloying components at the “coating–base” interface, with the formation of elements of the metallurgical connection, contributes to a significant increase in wear resistance and a decrease in the coefficient of friction due to the formation of secondary ultradispersed film structures. We consider laser thermocycling of plasma coatings is an effective method of improving their quality and strength of adhesion to the base.