Plasma sprayed Mo–Mo oxide nanocomposites: synthesis and characterization

Atmospheric plasma spray has been employed to deposit Mo/Mo oxide coatings on a steel substrate held at 190 and 440°C. The deposits have been characterized primarily by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Different forms of Mo-oxide, including MoO2, Mo4O11, Mo8O23 and MoO3 have been observed along with Mo as a primary phase. MoO2 particles with a size range of 5–10 nm have been observed to be embedded in the Mo deposit. These nano-particles show a definite orientation with respect to Mo. It is concluded from our study that the liquid-Mo particles pick up oxygen, primarily in-flight, and solidify having various oxide stoichiometries.