Correlation between growth texture, crystallite size, lattice strain and corrosion behavior of copper-carbon nanotube composite coatings

Abstract

This study illustrates the correlation between corrosion properties, preferred growth orientation, crystallite size, size distribution, and lattice strain in electrodeposited Cu and Cu‑carbon nanotubes (CNT) composite coatings with different CNT additions. Cu-CNT composite coatings were electrodeposited over mild steel substrate by dispersing different CNTs into the electrolyte bath. Lower CNT incorporation enhanced the coating compactness and produced finer coating morphology. In contrast, higher CNT amounts produced rougher and defective coating morphology primarily due to the agglomeration of CNTs. The crystallite size, size distribution, preferred growth orientation, and strain in the coatings were sensitive to the CNT amount. With increasing CNT addition, growth along (111) planes was preferred. With continued CNT addition, crystallite size, size distribution, and lattice strain initially decreased to the lowest value, and then it increased at higher CNT additions. A similar trend of initial decrease followed by increase was also observed for the coatings' corrosion rate with continued CNT addition. The optimum CNT amount produced the lowest corrosion rate also yielded maximum growth along the low energy (111) planes, smallest crystallite size, lowest size distribution and lowest lattice strain.