| Abstract: |
Technical feasibility of cold spraying MCrAlY coatings, in particular for repair and build-up parts, has been reported as a viable alternative option in lieu of the traditional HVOF and LPPS processes. Despite of its numerous advantages, for e.g., low porosity (dense coatings), excellent bond strength, lower oxide content etc., one of the main drawbacks of cold spray has been its lower powder spray rates (H27 g/min Vs. 40 g/min for HVOF & LPPS). In the present study the sprayability of annealed CoNiCrAlY (Amdry 995 type) alloy feed-stock material was investigated. The as-sprayed and post-sprayed heat-treated coatings generated with the annealed feed-stock were investigated for its influence on bond strength, micro-hardness, porosity and surface morphologies. These cold sprayed coatings were compared and contrasted with the more traditional LPPS generated coatings. Cold spray coatings, produced by Sulzer Metcos Kinetiks 8000, were deposited on Inconel 718 substrates. Nitrogen was utilized both as a propellant and powder carrier gas. A comprehensive characterization of the associated properties of the as-sprayed and heat-treated coatings for both the cold sprayed and LPPS coatings were also investigated.
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