Isotropic Sm-Fe-N bonded magnets were obtained by additive manufacturing(AM). The technique used was the so-called powder bed fusion(PBF) and the feedstock was composed of a polymeric binder(PA-12) and Sm-Fe-N flake p...Isotropic Sm-Fe-N bonded magnets were obtained by additive manufacturing(AM). The technique used was the so-called powder bed fusion(PBF) and the feedstock was composed of a polymeric binder(PA-12) and Sm-Fe-N flake particles(Nitroquench-P). The AM set-up equipment uses a computer-controlled CO2 laser beam to melt the binder and constructs magnets layer-by-layer. In order to develop this study, a cylinder with 10 mm of both height and diameter was selected as the shape of samples. Specimens were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). Magnetic properties were measured in a hysteresis graph. XRD results indicate that there is no degradation of the main magnetic phase(SmFe7 Nx). In the AM component, porous regions were identified on SEM micrographs, as well as magnetic particles and polymeric binder. Remanence values(Br) as great as 0.3 T are achieved, while intrinsic coercivities remain in the range from 616 up to 642 kA/m. An additional isostatic compression of the parts results in greater remanence, which is directly proportional to the density increase. Coercivity is also sensitive to the porosity decrease, probably due to a better interlocking of particles. Current results indicate AM as a promising route for near net-shape manufacturing of Sm-Fe-N permanent magnets, a market niche yet to be widely explored.展开更多
文摘Isotropic Sm-Fe-N bonded magnets were obtained by additive manufacturing(AM). The technique used was the so-called powder bed fusion(PBF) and the feedstock was composed of a polymeric binder(PA-12) and Sm-Fe-N flake particles(Nitroquench-P). The AM set-up equipment uses a computer-controlled CO2 laser beam to melt the binder and constructs magnets layer-by-layer. In order to develop this study, a cylinder with 10 mm of both height and diameter was selected as the shape of samples. Specimens were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). Magnetic properties were measured in a hysteresis graph. XRD results indicate that there is no degradation of the main magnetic phase(SmFe7 Nx). In the AM component, porous regions were identified on SEM micrographs, as well as magnetic particles and polymeric binder. Remanence values(Br) as great as 0.3 T are achieved, while intrinsic coercivities remain in the range from 616 up to 642 kA/m. An additional isostatic compression of the parts results in greater remanence, which is directly proportional to the density increase. Coercivity is also sensitive to the porosity decrease, probably due to a better interlocking of particles. Current results indicate AM as a promising route for near net-shape manufacturing of Sm-Fe-N permanent magnets, a market niche yet to be widely explored.
