Abstract
An important growth potential in thermal spraying industry consists of the development of new coating materials. Metal- or Ceramic-Matrix-Composites (MMC / CMC) are of special interest due to a variety of properties which can be influenced particularly by the ratio of matrix and reinforcing material. Thermal sprayed coating properties mainly depend on thermal and kinetic energy of the spray particles. An increase in thermal energy of sprayed particles can be obtained by Self Propagating High Temperature Synthesis (SHS) reaction between components of the spray material. Hence a higher adhesive strength, a lower porosity and an increased deposition efficiency can be expected. Aluminium-based spray materials, containing metal oxides, are suitable for the Self Propagating High Temperature Synthesis to produce MMC-coatings. For good contact between the reactants, powders of aluminium and chromium oxide for plasma spraying were prepared by mechanical alloying. Coatings characterization results on the base of optical microscopy, scanning electron microscopy (SEM), X-ray structure analysis (XRD) and measurements of velocity and temperature with a DPV2000 system. The plasma spraying process combined with SHS reaction of the spray material leads to raised enthalpy of spray particles combined with an increased ad-/cohesive strength and a lower porosity as well as an increased deposition efficiency.
