Surface modification of atmospheric plasma sprayed cermet coatings by plasma transferred arc method

ABSTRACT

AISI 8620 steel substrates were coated with WC–Co and Cr₃C₂–NiCr by using the atmospheric plasma spraying (APS) method. Subsequently, surface melting of samples coated with APS was performed at different current values using the plasma transfer arc (PTA) method. Microstructure, microhardness, and wear properties of as-sprayed and surface-modified coatings were investigated. The microstructure of the APS-coated surface had some voids, cracks and nonhomogeneous areas. These defects were eliminated with the PTA surface modification process and microstructural properties of coatings were improved. The wear resistance of PTA modified coatings was also increased. The highest wear resistance and microhardness were obtained in WC–Co coating modified by PTA at a current of 80 A. The wear resistance of this coating was 8.5 times higher than that of the substrate. The coating hardness reached values as high as 980 HV_0,1 in this coating.

KEYWORDS:

• Atmospheric plasma spray
• plasma transferred arc welding
• wear
• microstructure

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

İ. Bayar http://orcid.org/0000-0002-4187-3911

M. Ulutan http://orcid.org/0000-0003-1821-6486