Creation of Protective Coatings on the Working Surfaces of Machine Parts by High-Velocity Flame Spraying

The use of supersonic flame spraying on a mass scale is limited because of insufficient information on the properties of protective coatings formed by this method from various types and systems of powder materials. Here, we substantiate the possibility of using supersonic flame spraying to create protective coatings on machine parts for various functional purposes. The characteristics of the coatings are determined and compared; they demonstrate the advantages of this method compared to subsonic gas-thermal coating formation methods. The aim of this work is to study the physical and mechanical properties of coatings formed by high-velocity flame spraying under various conditions. The coatings are deposited onto samples using the Plakart-HV2 robotic complex for high-velocity flame (HVOF) spraying. WC–Co–Cr 86-10-4 and PR‑Kh14N7S3R3 powder materials are used to form the coatings. Metallographic examination of the sprayed coatings is carried out according to generally accepted methods. Dense, wear-resistant coatings with a maximum hardness of 1475 HV are found to be formed from the WC–Co–Cr 86-10-4 powder by supersonic flame spraying under rational conditions. The high microhardness of the coatings made from this powder mixture is caused by the presence of WC in their structure. When the PR-Kh14N7S3R3 powder material is used, the maximum microhardness is about 927 HV. The properties of the coatings produced by supersonic flame spraying depend on the powder material composition and their formation conditions. The characteristics of the formed layers can be changed over a wide range by varying the process conditions and the content of elements in the sprayed powder material, which enables the production of coatings with the required physical and mechanical properties.