Study on preparation and tribological properties of as-sprayed 8YSZ/Graphite coating

ABSTRACT

The mechanical and tribological properties of the metal components can be improved by spraying ceramic coatings, but the ceramic coatings are not anti-friction. Thus we mixed nickel cladded graphite into 8YSZ (ZrO₂  + 8wt-%Y₂O₃) powders, hoping to improve the tribological characteristics of the as-deposited 8YSZ coating. Meanwhile, the 8YSZ-Ni/Graphite coating is deposited at a substrate temperature of 500°C to tune its microstructure and mechanical properties. The results demonstrate that the graphite uniformly distributed in the composite coatings and was hardly oxidized during spraying. The friction coefficient of 8YSZ-Ni/Graphite-RT coating is lower than that of 8YSZ coating due to the formation of graphite lubricating layer. The increase of defects leads to a decreasing tendency in the hardness and wear resistance. As the substrate temperature rises to 500°C, the mechanical and anti-wear properties of 8YSZ-Ni/Graphite coating are significantly improved.

KEYWORDS:

• Thermal spray
• substrate preheating
• microstructure
• tribological properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors appreciate the financial support of the West Light Foundation of the Chinese Academy of Sciences, the Youth Innovation Promotion Association of Chinese Academy of Sciences under [grant no. 2014378], and the Science and Technology Program of Gansu Province under [grant no. 17JR5RA300].