Detonation Spraying of Cr3C2-NiCr Coatings and Their Properties

Detonation spraying of wear-resistant Cr3C2-NiCr coatings was carried out using a two-fuel 0.61C2H2 + 0.26C3H8 + O2 explosive mixture. The coatings were formed from agglomerated powders containing 10, 20 and 25 wt.% of the nichrome binder. The deposition efficiency was measured. The microstructure, bonding strength, hardness and wear resistance of the coatings were studied as functions of the spraying distance and spraying angle. The coatings of the highest quality had a porosity of less than 0.5%. Irrespective of the binder content, the bonding strength of the coatings was equal to or greater than 150 MPa. In the ASTM G-65 abrasion test, the volume loss of Cr3C2-20NiCr coating was 3.1 mm3/1000 rev. In addition, the level of residual stress was evaluated using the Almen test. The coatings of the highest quality possessed compressive residual stresses. For applications under wear conditions and increased mechanical loads, a coating containing 20% of NiCr binder is recommended. The results of this study can be useful for selecting the modes of the coating deposition on components of complex shape.