Platinum and Iridium Coatings Obtained by Double Glow Plasma Technology

摘要

Pt and Ir coatings were produced by double glow plasma technology on the surface of Ti alloy substrates. The chemical compositions of the coatings were determined by X-ray diffraction and X-ray photoelectron spectroscopy. The microstructure and morphology of the coatings were observed by scanning electron microscopy. The hardness and elastic modulus of the coatings were estimated by nanoindentation. The measurements of adhesive forces of the coatings were performed with scratch tester. The results indicated that the Pt and Ir coatings displayed the preferred (220) orientation due to the initial nuclei with preferred growth on the surface of the substrates. The interface between the Pt coating and substrate exhibited no evidence of delamination. The Ir coating was composed of irregular columnar grains with many nanovoids at the interface between the coating and substrate. The mean values of hardness for Pt and Ir coatings were 0.9 GPa and 9 GPa, respectively. The elastic modulus of Pt and Ir coatings were 178 GPa and 339 GPa, respectively. The adhesive forces of the Pt and Ir coatings were about 66.4 N and 55 N, respectively. The Pt and Ir coatings adhered well to the Ti alloy substrates.