Thermal Stability, Hardness, and Corrosion Behavior of the Nickel–Ruthenium–Phosphorus Sputtering Coatings

Nickel–ruthenium–phosphorus, Ni–Ru–P, alloy coatings were fabricated by magnetron dual-gun co-sputtering from Ni–P alloy and Ru source targets. The composition variation and related microstructure evolution of the coatings were manipulated by the input power modulation. The as-prepared Ni–Ru–P alloy...

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Bibliographic Details
Published in:Coatings (Basel) 2020-08, Vol.10 (8), p.786
Main Authors: Hsiao, Yu-Cheng, Wu, Fan-Bean
Format: Article
Language:English
Subjects:
Annealing
Coatings
Corrosion potential
Corrosion resistance
Crystallization
Degeneration
Electrodes
Heat treatment
Nanocrystals
Nickel base alloys
Phases
Phosphorus
Pitting (corrosion)
Ruthenium
Sputtering
Surface hardness
Temperature
Thermal stability
Thin films
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Summary:Nickel–ruthenium–phosphorus, Ni–Ru–P, alloy coatings were fabricated by magnetron dual-gun co-sputtering from Ni–P alloy and Ru source targets. The composition variation and related microstructure evolution of the coatings were manipulated by the input power modulation. The as-prepared Ni–Ru–P alloy coatings with a Ru content less than 12.2 at.% are amorphous/nanocrystalline, while that with a high Ru content of 52.7 at.% shows a feature of crystallized Ni, Ru, and Ru2P mixed phases in the as-deposited state. The crystallized phases for high Ru content Ni–Ru–P coatings are stable against annealing process up to 600 °C. By contrast, the amorphous/nanocrystalline Ni–Ru–P thin films withstand a heat-treated temperature up to 475 °C and then transform into Ni(Ru) and NixPy crystallized phases at an annealing temperature over 500 °C. The surface hardness of the Ni–Ru–P films ranges from 7.2 to 12.1 GPa and increases with the Ru content and the annealing temperatures. A highest surface hardness is found for the 550 °C annealed Ni–Ru–P with a high Ru content of 52.7 at.%. The Ecorr values of the heat-treated amorphous/nanocrystalline Ni–Ru–P coatings become more negative, while with a high Ru content over 27.3 at.% the Ni–Ru–P films show more negative Ecorr values after annealing process. The pitting corrosion feature is observed for the amorphous/nanocrystalline Ni–Ru–P coatings when tested in a 3.5M NaCl solution. Severer pitting corrosion is found for the 550 °C annealed Ni–Ru–P coatings. The development of Ni(Ru) and NixPy crystallized phases during annealing is responsible for the degeneration of corrosion resistance.
ISSN:2079-6412
2079-6412
DOI:10.3390/coatings10080786