Increase in the heat resistance of carbon steels by thermodiffusion treatment and vacuum coating application

Abstract

In this article is substantiated the hypothesis of the possibility of increasing the heat resistance of hypoeutectoid carbon steels by preliminary thermal diffusion alloying followed by the application of vacuum nitride coatings. It was established that thermal diffusion layers obtained as a result of saturation with boron and aluminum have the greatest heat resistance in terms of relative mass gain, then in order of decreasing heat resistance: layers obtained as a result of saturation with boron and silicon, boron and chromium, boron and nitrogen, and as a result of boriding. New composite coatings of heat-resistant compositions “thermodiffusion layer – vacuum ion-plasma coating” have been developed, which are also solid, wear-resistant, and corrosion-resistant under atmospheric corrosion, solutions of salts and certain acids. The influence of ionic-plasma coatings on additional increase in heat resistance of steels with the produced thermodiffusion layers, during which the most efficient compositions of the developed coatings are defined and given to improve the temperature resistance of the surface, was assessed. The results of the calculation of the predicted heat resistance of the developed compositions “diffusion layer – ion-plasma coating” on hypoeutectoid carbon steels are given in the article.