Nanocomposite powder for powder-bed-based additive manufacturing obtained by dry particle coating

Abstract

Several dry processing techniques are assessed to elaborate metallic nanocomposite powders dedicated to powder-bed-based (PBB) additive manufacturing as laser-powder bed fusion (L-PBF) and Binder Jetting (BJ). Electrostatic assembly of nanosized silicon carbide (35 nm) particles at the surface of gas atomized aluminium powders (15-53 μm) is performed using mixers covering a range of mixing energy from rotative drum mixer to high energy mixers such as high shear paddle and acoustic mixers. Analyses of particle size distribution (PSD) of powders mixtures show that only high-energy mixers bring to a monomodal PSD describing a complete electrostatic assembly of nanoparticles. Statistic image analysis confirms the absence of plastic deformation of aluminium particles during mixing. The coating leads to a drastic increase of starting host powder flowability and apparent density, while reducing the host powder optical reflectivity. Finally, a surface oxidation of SiC nanoparticles affects the coating efficiency.