Abstract
TaSiCN composite coatings were deposited on Ta alloy substrates by radio frequency sputtering with different N2 gas flow rates. The composition, microstructure, and NaCl-KCl molten salt corrosion resistance of the coatings were investigated. The results showed that all TaSiCN coatings consist of TaN, TaC and Ta(C,N) nano-crystalline, amorphous SiCx, SiNx, CNx and sp2 amorphous carbon. With increasing N2 gas flow rate, the N content of the coatings increased from 20 at% to 35 at%, the C content decreased from 48 at% to 34 at%, and the content of Ta and Si remains slight change. In comparison with Ta alloy substrate, the samples with TaSiCN coatings exhibited better corrosion resistance against NaCl-KCl molten salt at 750 °C, where the coating with the N content of 28 at% displayed the best corrosion resistance. The corrosion products of the coatings mainly included Ta2O5, Na2Ta4O11, and SiOx, etc. The corrosion mechanism of TaSiCN coatings could originate from a cyclic process of passivation, penetration, stripping, and repassivation. Our study could provide a potential corrosion resistant coating for the electrolytic crucible of pyrochemical processes.
Published Version
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