Effect of Y2O3 addition on the microstructure and properties of NiCoCrAlYTa coatings prepared by electrospark deposition: From a perspective of thermal physical properties.

Oxide dispersion strengthened (ODS) NiCoCrAlYTa coatings with different Y 2 O 3 additions (0, 3, 5 and 10 wt%, respectively) were prepared by electrospark deposition (ESD), and the effect of Y 2 O 3 addition on the thermal physical properties of the electrodes was investigated. The relationship between the thermal physical properties and the microstructure and properties of the coatings was studied in detail. The results show that, with the increase of Y 2 O 3 addition, the thermal diffusivity and the thermal conductivity were decreased at first and then increased when 10 wt% Y 2 O 3 was added, which influenced the deposition process and the deposition efficiency. Most of the Y 2 O 3 particles were transformed into Y-Al-O oxides, which were mainly consisted of Y 4 Al 2 O 9 and amorphous Y-Al-O oxides. The amorphous Y-Al-O oxides core was surrounded by a shell enriched in Ti, Ta, Cr, which could be identified as mixed oxides at the region adjacent to the core, and (Ta, Ti, Cr) intermetallic compound at the exterior zone of the shell. Y-Al-O oxides consumed the Al atoms and thus decreased the amount of β-NiAl, resulting in the variation of the microhardness, wear resistance and oxidation behavior. • Y 2 O 3 dispersed ODS MCrAlY coatings were prepared by electrospark deposition. • The addition of Y 2 O 3 influenced the thermal physical properties of the electrodes. • Thermal physical properties influenced the deposition efficiency and microstructure. • A Core (Y-Al-O oxides)-Shell ((Ti, Ta, Cr)-rich) structure was formed. • β-NiAl was transformed into γ-Ni, changing of microstructure and oxidation behavior. [ABSTRACT FROM AUTHOR]