Obtaining and characterization of multilayer nickel thin films electrodeposited with the assistance of ultrasonic agitation

Abstract

Multilayer composite structures of electrodeposited Ni films on polycrystalline copper substrates were fabricated with the assistance of ultrasonic agitation. Alternate ordinary and ultrasonicassisted electrodeposition of Ni layers allowed the formation of laminated films. The adhesion and hardness properties were characterized using bidirectional bending test and Vickers microhardness test with different loads. Dependence of composite microhardness and film adhesion on layer thickness was investigated. It was confirmed that densified parallel interfaces give rise to high hardness and strength of composites. Model of Korsunsky was chosen and applied to experimental data for obtaining the film hardness and model of Chen-Gao was applied for the adhesion evaluation. Compared with the conventional electrodeposited Ni films, the mechanical properties of the ultrasonic-assisted multilayer Ni films are improved. The microhardness and adhesion of the films are enhanced by introduction of ultrasound and by reducing the layer thickness in the film.