Atmospheric plasma spray has been employed to deposit Mo/Mo oxide coatings
on a steel substrate held at 190 and 440 degreesC. The deposits have been c
haracterized primarily by transmission electron microscopy (TEM), X-ray pho
toelectron spectroscopy (XPS) and X-ray diffraction (XRD). Different forms
of Mo-oxide, including MoO2, Mo4O11, Mo8O23, and MoO3 have been observed al
ong 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 st
udy that the liquid-Mo particles pick up oxygen, primarily in-flight, and s
olidify having various oxide stoichiometries. (C) 2001 Elsevier Science B.V
. All rights reserved.