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7394 |
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Thursday, May 05, 2022, Hall G2 2:00 PM Medical Industry |
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Hydroxyapatite coating by cold gas spraying: interest of a PEEK sublayer |
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Dylan Chatelain* / IRCER, France Vincent Guipont / Ecole des Mines Paristech, France Alain Denoirjean/ IRCER, France Fabrice Rossignol/ IRCER, France Nicolas Tessier Doyen/ IRCER, France |
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Cold spray is based on the acceleration at a supersonic velocity (up to 1200 m.s-1) of unmelted powder particles through a de Laval nozzle by a high-pressure gas (e.g. N2). As the powder is not molten in the gas, the deposit is mostly generated by the powder plastic deformation and/or brittle fragmentation and its mechanical anchorage when impacting the substrate at high kinetic energy. Up to date, cold spray has been mostly dedicated to ductile materials (i.e. metals). However, cold spray of brittle materials (i.e. ceramics) has recently gained attention. In the specific case of ceramics, the challenge consists mostly in controlling the powder fragmentation at the impact to optimize the coating quality (i.e. low porosity and good mechanical adhesion) and its construction rate. In medical area, hydroxyapatite is usually coated on TA6V. However, it is difficult to build a qualitative coating on such a hard material. The idea in this work is to spray a thin PEEK sublayer on the TA6V to make the impact of the hydroxyapatite more plastic, and help in constructing the deposit. Indeed, in thermal spraying, the nature of the first layer is very important especially to avoid delamination. Thanks to PEEK utilization, the anchorage of the first layer is better than without sublayer, and the growth of the coating is easier too. |