Role of micro- and nano-CeO 2 reinforcements on characteristics and tribological performance of HVOF sprayed Cr3C2-NiCr coatings

• The present study investigates the role of micro- and nano-CeO2 reinforcements on microstructural, mechanical and tribological properties of Cr3C2-NiCr coatings deposited using high-velocity-oxy-fuel (HVOF) spray process. A novel blending method involving ultrasonication, magnetic stirring and 3D-tumbler mixing was used to prepare the micro- and nano-CeO2 reinforced Cr3C2-NiCr feedstock powders. Unreinforced Cr3C2-NiCr coatings were also prepared for comparison purposes. X-ray diffraction, FE-SEM, EDS mapping, optical microscopy and optical profilometry were used to characterize the coatings. Tribological studies were performed on the coatings using modular ball-on-disc tribometer. The results showed that nano-CeO2 reinforced coatings yielded considerable reduction in porosity, surface roughness and CoF values while significantly enhancing the hardness and fracture toughness in comparison to the micro-CeO2 reinforced and unreinforced Cr3C2-NiCr coatings. The addition of nanoCeO2 to the coatings contributed to the microstructure refinement and to the formation of stable tribo-oxide layer, resulting in a lower specific wear rate under identical test conditions. Performance of micro-CeO2 reinforced coatings was intermediate to that of nano-CeO2 reinforced and unreinforced Cr3C2-NiCr coatings.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

Nyckelord

Microstructure refinement

Cr3C2-NiCr

HVOF

Ultrasonication

Wear

Production Technology

Produktionsteknik

Publikations- och innehållstyp

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