ANALYSIS OF FACTORS INFLUENCING THE ADHESIVE STRENGTH OF ELECTROMETALLIZING COATINGS

Increasing adhesion strength of coated surfaces with the method of electric arc metallization (EM) is an important task in the restoration of machine parts. The study aims at determining the factors allowing to increase the adhesion strength of deposited EM coatings due to the preliminary surface preparation – applying an underlayer, selecting EM and the aerosol fluxing (AF) modes). The paper presents methods for studying the speed of sprayed metal particles, adhesive strength and wear resistance of EM coatings, as well as the study results of the speed of sprayed metal particles depending on the metallization distance, the effect of preliminary preparation methods and aerosol fluxing on the adhesion strength of coatings applied to steel 18 ХГТ by the EM method. The paper presents methods and results of wear resistance study of EM coatings, which are of interest to determine a possibility of using coatings obtained by the EM method with the AF application in the repair industry. It has been established that the highest speed of sprayed material particles is achieved at a metallization distance of 140 mm. It has been shown that blasting with corundum is the preferred method of pretreatment for steel coatings with high hardness. It has been found that deposition of EM coatings with wire Св-08Г2С increases the sprayed coating adhesion strength. The use of AF allows to increase the wear resistance of a friction couple with an EM coating obtained by spraying the Св-08Г2С wire in 1.2 times, as compared to a friction couple with an EM coating obtained using a 50ХФА wire and in 1.4 times as compared to a reference friction couple. The research results allow to recommend the application of the EM coatings deposited using AF in the repair industry for restoring and strengthening steel parts to be used for various purposes.