An Investigation on the Wear and Corrosion Behavior of HVOF-Sprayed WC-12Co-Al{sub 2}O{sub 3} Cermet Coating

Journal Article · Thu Mar 15 04:00:00 EDT 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3240-Y· OSTI ID:22858009

Chakradhar, R. P. S.; Prasad, G. ^[1]; Venkateswarlu, K. ^[2]; Srivastava, Meenu ^[1]

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1. CSIR-National Aerospace Laboratories, Surface Engineering Division (India)
2. CSIR-National Aerospace Laboratories, Materials Science Division (India)

The aim of the present study is to develop thermally sprayable WC-12Co and WC-12Co-xAl{sub 2}O{sub 3} (x = 10 and 15 wt.%) cermet coatings on steel substrate (SS 304) by high-velocity oxy fuel (HVOF) method. Influence of Al{sub 2}O{sub 3} addition on the wear and corrosion behavior of WC-12Co coating has been studied. The microstructure and chemical composition of the coatings were analyzed using field emission scanning electron microscope (FESEM), and phase identification was carried out using x-ray diffraction (XRD) studies. The morphology of the coating appears as coarse granular structure. The XRD studies revealed the presence of hexagonal WC phase along with η-Co{sub 6}W{sub 6}C phase. It has been observed from the microhardness measurements, that the values gradually increase from 950 to 1300 HK with the addition of Al{sub 2}O{sub 3} from 0 to 15 wt.%. The wear rate of WC-12Co-15Al{sub 2}O{sub 3} (3.19 × 10{sup −6} mm{sup 3}/Nm) and WC-12Co-10Al{sub 2}O{sub 3} (5.26 × 10{sup −6} mm{sup 3}/Nm) coatings was seen to be one order of magnitude lower than that of WC-12Co (2.9 × 10{sup −5} mm{sup 3}/Nm) coating. The polarization studies revealed that WC-12Co-15Al{sub 2}O{sub 3} cermet coating showed superior corrosion protection than that of WC-12Co-10Al{sub 2}O{sub 3} and WC-12Co coatings. This has been attributed to the gradual decrease in the porosity levels with an increase in Al{sub 2}O{sub 3} content which is supported by morphology studies. The microhardness and wear behavior of WC-12Co-Al{sub 2}O{sub 3} coatings are equivalent to those of hard chrome suggesting the possibility of its replacement.

• OSTI ID: 22858009
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 3 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CERMETS
CHEMICAL COMPOSITION
COATINGS
COBALT
CORROSION
CORROSION PROTECTION
FIELD EMISSION
MICROHARDNESS
MICROSTRUCTURE
POLARIZATION
POROSITY
SCANNING ELECTRON MICROSCOPY
STEELS
SUBSTRATES
TUNGSTEN CARBIDES
X-RAY DIFFRACTION