Elucidation of the Structural Texture of Electrodeposited Ni/SiC Nanocomposite Coatings

Crystallographic texture is one of the most sensitive parameters for controlling the microstructure of electrodeposited layers. In this work, we study the crystallographic texture of electrodeposited nickel silicon carbide coatings. The nickel coatings containing SiC nanoparticles and microparticles were electrodeposited from an additive-free sulfate bath containing nickel ions and SiC particles. The effect of current density on the codeposited Ni/SiC was studied. The coatings were analyzed with scanning electron microscopy and X-ray diffraction. Pole figure studies were done to characterize the evolved crystallographic texture. The X-ray scans followed by Rietveld analysis using the Rietquan program were used for the determination of texture, lattice parameter, and grain size of the matrix. The Ni/SiC nano-electrocomposites, prepared at 7 A/dm(2), exhibited improved properties in comparison to pure nickel electrodeposits. The properties of the composite coatings are associated with structural modifications of the nickel crystallites as well as the morphology of the electrodeposited layers. For the optimum current density, the preferred orientation is < 110 >. Grain refinement is observed for an optimum range of 7-10 A/dm(2) associated with the evolution of the < 110 > texture toward a less marked < 210 > texture. From pole figure and inverse pole figure studies, a mechanism of crystallographic texture changes as a function of current density and pH values of the electrolyte bath is proposed.