ABSTRACT
Vacuum plasma sprayed (VPS) is one of the most frequently used thermal spray processes for deposition of high temperature oxidation resistant materials such as McrAlY alloys onto turbine parts. For correlation analysis a statistical factorial plan was used to assess the effects of the parameters. Coatings were also subjected to cyclic oxidation tests to determine potentials for replacing VPS coatings. The oxide and nitrogen content of the coatings were evaluated using an O2N2-analyser after peeling them from the substrate, oxygen units are in wt% or ppm. Cyclic oxidation tests revealed that high-velocity oxygen-fuel (HVOF) coatings can compete very well with VPS ones. Influences of HVOF parameters on coating microstructure and oxygen content were investigated by statistical means. Reactive plasma spraying is an appropriate tool to increase reactive gas content in coatings aimed at hard phase formation. The nitrogen content could be increased by a factor of 100 from the initial powder.
