Plasma sprayed CoNiCrMoNb(BSi) high-entropy amorphous alloy coating: The effect of spraying power on microstructure, mechanical and tribological properties

Plasma spraying was used to fabricate the CoNiCrMoNb(BSi) high-entropy amorphous alloy (HEAA) coatings. The microstructure, mechanical, and tribological properties of these coatings were studied as a function of spraying power. The results show that the as-sprayed coating was composed of an amorphous phase and a minor FCC phase. An increased amorphous content was obtained at an increased spraying power, leading to improvements in hardness and wear resistance. However, the porosity in the coatings got worsen when the power levels were insufficient or excessive, which deteriorated the mechanical and tribological properties of these coatings. The spraying power was optimized to 45 kW to provide a higher amorphous content and reduced porosity, resulting in improved hardness and increased wear resistance. This study has clarified the techniques used to tailor the microstructure in the plasma spraying process, as well as the fundamental principles for enhancing the mechanical and tribological properties. These findings hold considerable importance for the practical applications of HEAA coatings in engineering. In summary, the results suggested that the manipulation of spraying power was crucial in achieving a substantial amorphous phase and preventing the occurrence of porosity in plasma -sprayed HEAA coatings.