Growth mode and characterizations of electrodeposited Re thick films from aqueous solutions with additives on Cu (110) + (311) substrates

Abstract

Rhenium (Re) thick films were electrodeposited on copper (Cu) substrates with (110) + (311) texture from aqueous solutions with additives of 2 g l−1 gelatin, 1 mM sodium lauryl sulfate, and 1 mM vanillin. The microstructure and morphology of the films with different thickness values were characterized by scanning electron microscopy and atomic force microcopy. The chemical composition and the crystallographic structure of the films were identified by energy dispersive spectroscopy and x-ray diffraction, respectively. Re thick films were obtained due to the synergistic effect of additives. The additives had a significant influence on electrodeposition of the films. The microstructure and growth mode of Re films were influenced by surface topography and orientation texture of the substrate. The deposition rate was about 0.064 mg min−1. Re thin films adhered well to the substrate with no evidence of delamination and cracking. However, the Re thick film was not stable, fine microcracks were present, and even delamination occurred in vacuum condition due to large residual stress in the deposits or the shrinkage from decomposition of Re hydrides in the vacuum environment. Re films consisted of an amorphous phase structure. The Re film had a high hardness of 349 ± 15 VHN and exhibited a Stranski–Krastanov growth mode.