Structure and properties of electrodeposited functional Ni–Fe/TiN nanocomposite coatings

• Ni–Fe/TiN nanocomposites were electro-co-deposited from sulfamate-DMF bath.
• Effect of current density on wt.% incorporation of TiN was studied.
• TiN particles modify the microstructure of the matrix metal.
• Crystallite size was found between 7 nm to 13 nm with superior hardness.
• Deposits showed ferromagnetism but above 590 K transformed to anti-ferromagnetic.

Ni–Fe/TiN nanocomposite coatings were successfully prepared by cathodic co-deposition using nickel sulfamate, ferrous sulphate and N,N-dimethylformamide. The influence of the applied current density on the chemical composition, morphology, crystallography, hardness and electrical property of the coatings was investigated. A maximum of 18.73 wt.% TiN particles was incorporated in the Ni–Fe alloy matrix at 3.0 A dm− 2 and 45 °C from a bath containing 5 g/L of TiN particle suspension. The TiN particles were distributed uniformly in the matrix phase with little agglomeration. The TiN nanoparticles once incorporated in the composite coating promoted the nucleation of the matrix grains. The incorporation of TiN nanoparticles in the Ni–Fe alloy matrix caused a distinct microstructural change from uniform granular in Ni–Fe alloy to ‘cauliflower-like’ morphology in Ni–Fe/TiN nanocomposites. Face-centered-cubic crystals of both the ceramic particles and the nanocomposite coatings were observed. The crystallite size and the microstrain of the composites were found below 15 nm and < 0.0085, respectively. An improvement in the microhardness of the composites over the electrodeposited Ni and Ni–Fe alloy was recorded. Heat treatment led to slight grain growth and decrease in microhardness. The deposits have shown ferromagnetic characteristic.

Figure optionsDownload high-quality image (322 K)Download as PowerPoint slide