Influence of heat-treatment on mechanical, tribological and erosion properties of thermally sprayed NiCrBSi self-fluxing alloy compared with NiCrBSi-WC self-fluxing tungsten carbide blend

Heat treatment of thermally sprayed self-fluxing coatings is method capable of sealing coating porosity without using any other additives. This advantage is mainly beneficial for applications in corrosive environments. This method also brings other advantages in form of increased coating adhesion and many others, which were tested for the purpose of this paper. The benefits are based on positive enhancement of coating microstructure during this method and results in removing inhomogeneities introduced into a coating during thermal spraying process. This paper presents results of mechanical, erosion and wear properties of specimens coated by NiCrBSi self-fluxing ally and NiCrBSi-WC self-fluxing blend and describes differences between used heat treatment methods. The specimens were deposited using Flame spray (FS) and High-velocity-oxygen-fuel (HVOF) thermal spraying technologies and heat treated by different technologies. The resulting coatings were tested using the erosion resistance test along with measurements of basic mechanical properties (HR15N, HV0.3, roughness). Other conducted tests also included abrasion (ASTM G65) test and tribological (ASTM G99) test. The microstructure of the specimens was evaluated using optical microscopy and scanning electron microscopy.