Cold spray deposition on heated substrates

There exists a critical velocity above which the feedstock particles need to be accelerated to form a coating in cold spraying. The yield point of feedstock and substrate are important factors affecting deposition in cold spraying. A lot of effort has been focused by various researchers on developing cold spray equipment and parameters that will accelerate the feedstock above critical velocity to improve deposition. The current work looks at modifying the substrate yield strength to lower the critical velocity required for cold sprayed coating formation. Experiments have been conducted with substrate heating and related to the microstructures of the coatings. The results are explained on the basis of the lowering of the yield strength and increase in percentage elongation to the effect this has on the deposit formation. A model substrate 304 and Ni-20Cr feedstock was used for these experiments.