Synthesis and characterization of sputter-deposited Ni-rich Ni3Al hard coatings

• Published in: Journal of alloys and compounds 2022-12, Vol.926, p.166802, Article 166802
• Main Authors: Tiwari, Sunil Kumar, Rao, Akula Umamaheswara, Chawla, Vipin, Dubey, Paritosh, Saxena, Vikas, Chawla, Amit K., Avasthi, Devesh Kumar
• Format: Article
• Language: English
• Subjects: Aluminum; Chemical composition; Coatings; Hardness; High-temperature alloys; Hydrophobicity; Magnetron sputtering; Mechanical properties; Metals and alloys; Microstructure; Modulus of elasticity; Nanoindentation; Nickel aluminides; Silicon substrates; Surface roughness; Thin films; Vapor deposition
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.166802

Ni3Al and Nickel (Ni) rich Ni3Al thin films were deposited on Si (100) substrate by magnetron sputtering and co-sputtering process respectively. Variations in elemental composition, microstructure, surface topography, and mechanical properties were investigated as a function of Ni enrichment via EDS, SEM, AFM, and nanoindentation respectively. Results revealed that the hardness and young’s modulus decrease with increase in Ni content in the film. A maximum hardness of 12.75 GPa was achieved with the elemental composition of Al (20.8 at%) and Ni (79.2 at%). The increase in surface roughness as a result of Ni enrichment led to the increase in hydrophobic properties up to the elemental composition of Al (14.9 at%) and Ni (85.1 at%) beyond which it declined. This study shows that the surface roughness, microstructure, and elemental composition influence the mechanical and hydrophobic properties of the Nickel rich Ni3Al coatings. •The present work reports the alloy Ni3Al films with highest ever hardness of 12.5 GPa.•The study shows that with increase in concentration of Ni in Ni3Al film, hardness and young’s modulus decreases.•We have shown that the higher concentration of Ni in Ni3Al film results in higher surface roughness.