Effect of addition of Pd on electrodeposited Ni–B coatings

Abstract

In this study, the effect of addition of a noble metal (Pd) to the Ni–B nano-coating is studied. The Ni–B and Ni–B–Pd coatings are synthesized from aqueous electrolytes using direct current. The Ni–B coating is found to be dense, smooth, and shows a morphology consisting of clusters of grains. On the other hand, the Ni–B–Pd coating is found to be porous, highly rough and shows a stacked crystal type morphology. The addition of Pd has significantly improved the crystalline structure of the Ni–B coating, which in turn improved its thermodynamic stability. In spite of larger grain size, higher roughness and a defect structure, the Ni–B–Pd coating is found to exhibit approximately 40% higher hardness and 70% higher elastic modulus than that of the Ni–B coating. Also, it has been observed to possess almost three times better corrosion protection property than that of the Ni–B coating.