Plasma-sprayed Ti-6Al-4V coatings in a reactive nitrogen atmosphere up to 250 kPa

International audienceTwo spherical Ti-6Al-4V (25-45 µm and 45-75 µm) powders, were sprayed in a CAPS system ("Controlled Atmosphere Plasma Spraying") operating in a coupled mode: High-Pressure Plasma Spraying (HPPS) and Reactive Plasma Spraying (RPS). Four different pressure settings up to 250 kPa with reactive nitrogen atmosphere were tested in order to assess the influence of chamber pressure and chamber atmosphere on the deposition of Ti-6Al-4V coatings. The microstructures and phase compositions of the plasma sprayed Ti-6Al-4V coatings were studied using standard X-ray diffraction (XRD) and electron probe microanalysis (EPMA) with help of electron microscopy techniques (SEM and TEM). These established the pressure-assisted nitriding of the Ti-6Al-4V in the CAPS chamber with fine and coarse TiN precipitates embedded in a α-Ti matrix. A High-Pressure coupled with RPS enhanced the nitriding of the Ti-6Al-4V powder with a content of nitrogen which was all the higher because particle size was low

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