Measurement of Mechanical Properties of an Electroless Ni-B Coating Using Nanoindentation

Structure and mechanical properties of electroless nickel-boride (Ni-B) thin film coatings on S7 steel substrate were studied in as-plated and annealed samples. The electroless bath does not contain Pb, Cd, or Ta in the stabilizer agents. The mechanical properties of the Ni-B coatings were obtained from nanoindentation measurements. Models by Korsuslcy and King were used to obtain hardness and elastic modulus, respectively. The structure of the coatings was observed by atomic force and scanning electron microscopy and XRD. Bath composition, plating time, annealing temperature, and time were considered in order to prepare coatings with optimal mechanical properties.