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4648 |
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Thursday, May 12, 2016, Room 3E 10:00 AM Characterization & Testing Methods |
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Influence of powder characteristics on the microstructure and bond strength of cold sprayed aluminum coating |
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Pierre-Emmanuel Leger* / Ecole des Mines de Paris, FRANCE François Borit/ MINES ParisTech-Centre des Matériaux/C2P (Competence Center for Spray Processing), CNRS UMR 7633, BP87, France Nicole Fabregue/ MINES ParisTech-Centre des Matériaux/C2P (Competence Center for Spray Processing), CNRS UMR 7633, BP87, France Michel Jeandin/ MINES ParisTech-Centre des Matériaux/C2P (Competence Center for Spray Processing), CNRS UMR 7633, BP87, France Ducos Maurice/ MD Consultant, Route d'Uchaux, France |
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Cold spray aluminum coatings are today developed for a wide range of applications such as the repair of aircraft components, additive manufacturing or corrosion protection. However, powders specifically tailored for cold spray, are yet not available due to a rather low amount of results on the effect of powder characteristics on cold spray coatings properties. Powder parameters are numerous such as grain size, particle shape, particle microstructure or oxide content. The influence of these powder characteristics on the microstructure and bond strength of cold-sprayed aluminum coating was shown in this study. Aluminum powders with spherical and irregular shapes were selected for cold spray onto a steel substrate prepared using two different surface preparations. These powders were mixed with two alumina powders with either a spherical or an irregular particle shape to improve coating properties. The effect of powder characteristics on coating microstructure was studied using X-Ray diffraction, optical and scanning electron microscopy and microhardness testing. In addition, coating adhesion properties was studied using conventional pull-off testing and LASAT® (LAser Shock Adhesion Test). Experimental results were discussed in the light of several simulation of particle impact for various particle shapes. This study resulted in specifying some criteria to help cold spray users in selecting powders for their applications, according to economic and technical requirements. |