| Abstract: |
Heat treatment of thermally sprayed coatings is a post-treatment which is capable of sealing surface porosity without using any other necessary additives. This advantage is mainly beneficial in applications in corrosive environments. The benefits derive from the positive influence on coating microstructure and removing inhomogeneities introduced into a coating during thermal spraying process. The heat treatment allows to reduce inhomogeneities and the amount of porosity in the resulting coating, or to eliminate the porosity entirely. The paper presents the results of mechanical and tribological properties evaluation made on specimen of NiCrBSi alloy based coatings and describes differences between heat treatment methods. The specimens were deposited using thermal spraying technology (HVOF and FS) and heat treated by following methods - flame, electrical resistance and in furnace. The resulting coatings were tested using ASTM G65 (abrasion wear resistance), ASTM G99 (Pin-on-disc) and erosion resistance test along with measurements of basic mechanical properties (HR15N, HV0.3, roughness). The microstructure of the specimens was evaluated by optical microscopy.
Keywords: HP/HVOF, Flame spray, NiCrBSi, heat treatment, tribological properties, mechanical properties
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