Suspension Plasma Spraying of Self Lubricating Coating Systems

A couple of non stoichiometric phases in the system Ti-O show a reduction of their coefficient of friction under dry sliding conditions with rising temperature, being therefore sometimes called solid lubricants. But these homologous series tend to transform towards the rutile structure losing their good friction behavior.
To avoid this effect, the aim of this work was the stabilization of these phases by substitution of titania cations by several mono- and heterovalent cations. The resulting phases are homologous to Ti_nO_2n-1, but have the advantages of a better thermal stability and a broader area of formation in the resulting three-component system compared to the Ti-O-system. The nanosized feedstock powders where suspension plasma sprayed, as it allows achieving target stoichiometries by giving two precursors with the equivalent molar masses into the suspension and mixing them in the plasma. Furthermore the achievable coatings are very dense and thin and therefore allow an operation in fields where high demands towards the adhesion, cohesion and near net shape are made.