Abstract
Titanium suboxides form a class of ceramic materials possessing such technically interesting properties as electrical conductivity and solid lubrication. Consequently, these materials have a high potential for application as thermally sprayed coatings. In this paper the preparation and characterisation of two spray powders of different composition by agglomeration and sintering with a narrow range of the value n in TinO2n-1 is described. Powders were characterised by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), thermogravimetric measurements (TG), helium pycnometry, nitrogen adsorption and mercury intrusion techniques. The sprayability was tested by plasma spraying. The coating structures were studied by optical microscopy, XRD, TG and TEM. Although the powders were only partially oxidized as a result of the spray process, the crystallographic structure was changed significantly, according to XRD and TEM investigations. As an alternative method of preparation of titanium suboxide spray powders, the reduction of a fused and crushed spray powder with hydrogen is described. Powder particle shape and size distribution are not changed in this process.
