Interface interaction and structural transformation in particles of ceramic and cermet composite powders in flame spraying

The behavior of particles of Al₂O₃, TiO₂, Al₂O₃ - TiO₂, Al₂O₃ - Ni, ZrO₂ - Ni, Al₂O₃ - Ni- Ti powders in flame spraying has been studied. The interaction between the surface tension forces and the wetting forces has been found to produce either a melt shell around the particles core or drops of the second component on the surface of the core. Subsequently a total or partial capture of drops of the second component melt by the core melt or their separation during the movement within the plasma jet volume are possible. At high particle heating and cooling rates, polymorphous transformations, higher - to - lower oxide transformations and metastable phase fixations in the coating take place. These effects influence the conditions of ceramic powder plasma coating formation and also the properties of the coatings.