Effect of Zr content on structure property relations of Ni-Zr alloy thin films with mixed nanocrystalline and amorphous structure

摘要

A comparative study has been carried out on microstructural evolution, surface roughness, nanoindentation and scratch behavior, electrical resistivity, and corrosion resistance of Ni1-xZrx(0.13 ≤ x ≤ 0.40) thin films deposited on Si-(100) substrate by DC magnetron co-sputtering of high purity elemental targets in argon atmosphere. The film compositions have been examined by energy dispersive X-ray and Auger electron spectroscopy. Grazing incidence X-ray diffraction (GIXRD) studies have shown presence of Ni-rich solid solution, Ni3Zr and amorphous phase in all the films, with Ni5Zr being additionally observed in the Ni87Zr13film. Analysis of GIXRD data along with transmission electron microscopic studies have shown that volume fractions of both amorphous phase and Ni3Zr are increased, whereas the average crystallite size is decreased with increase in Zr concentration. Nanoindentation hardness and Young's modulus as well as electrical resistivity measured by Van-der Pauw four-probe method are influenced by volume fractions of both Ni3Zr and amorphous phase. Surface roughness and coefficient of friction obtained from atomic force microscopy and nano-scratch experiments, respectively decrease, whereas corrosion resistance in 3.5 wt% NaCl solution increase with Zr concentration primarily due to increase in amorphous phase content. Resistance to pitting corrosion is facilitated by formation of ZrO2-rich passive film, as confirmed by X-ray photoelectron spectroscopy.