Tribological properties and corrosion behavior of AC-HVAF sprayed nanostructured NiCrCoAlY-TiB2 coatings

In this paper, agglomerated and dense nanostructured NiCrCoAlY-TiB2 composite powders prepared by spray drying and plasma spheroidization were used for activated combustion high velocity air fuel (AC-HVAF) spray. The effect of sprayed powders on the microstructure, tribological properties and corrosion behavior of the ACHVAF sprayed coatings was systematically investigated. The present results demonstrate that plasma sphemidized powders are beneficial for dense microstructure and can effectively enhance coating's wear and corrosion resistance in turn. The coating sprayed by plasma spheroidized powders exhibits good wear resistance with the coefficient of friction of 0.48 +/- 0.01 and wear rate of 1.6 +/- 0.2 x 10(-5) mm(3) N-1 m(-1). The good wear resistance is mainly due to the uniformly distributed nanostructured TiB2, which can work as the hard-skeleton support. The electrochemical polarization tests and electrochemical impedance spectroscopy (EIS) analysis show that the good corrosion resistance can be attributed to the TiO2 and B2O3 oxide films formed on the surface and dense microstructure of as-prepared coatings.

Automated summary

The coatings sprayed by plasma spheroidized powders show good wear and corrosion resistance.