Magnetically hard Sm 2 ͑Co 0.8 Fe 0.2 ͒ 17 and SmCo 5 nanoparticles have been produced by using surfactant-assisted low-and high-energy ball milling techniques. Surfactants prevent the rewelding of the crashed particles during the milling process. Heptane was used as the milling medium and oleic acid as the surfactant. High-energy ball milling experiments took place in a milling vial with carbon steel balls by using an SPEX 8000M high-energy ball milling machine. The coercivity was found to increase with milling time with values of 2.3 kOe for Sm 2 ͑Co 0.8 Fe 0.2 ͒ 17 and 18.6 kOe for SmCo 5 after 4 h of milling. Transmission electron microscopy data showed that the milled powders consisted of nanoparticles with an average size of 5-6 nm and a narrow size distribution. Samples deposited on copper coated carbon grid showed self-assembled nanoparticles which could be further aligned when subjected to a magnetic field.

High-energy ball milling has been shown to be a promising method for large-scale fabrication of rare earth-transition metal nanoparticles. In this work, we report crystallographically anisotropic SmCo(5), PrCo(5) and Sm(2)(Co, Fe)(17) nanoparticles (particle size smaller than 10 nm) obtained by surfactant-assisted ball milling and study their size and properties as a function of the milling conditions. By milling nanocrystalline precursor alloys, we obtained SmCo(5) platelets (flakes) approximately 100 nm thick with an aspect ratio as high as 10(2)-10(3). The unusual shape evolution of this brittle material is attributed to its increased plasticity in the nanocrystalline state. The nanoflakes are susceptible to re-crystallization annealing and exhibit a room-temperature coercivity of up to 19 kOe. The successful fabrication of rare earth-cobalt nanoparticles and ultra-thin flakes provides hope for the development of nanocomposite permanent magnets with an enhanced energy product.

High energy ball milling has been shown to be a promising method for large-scale fabrication of rare earth-transition metal nanoparticles. In this work, magnetically hard Nd-Fe-B nanopowders with a coercivity in the range of 1.2-4 kOe have been produced by surfactant-assisted ball milling of nanocrystalline precursor alloys. The nanopowders consisted of Nd(2)Fe(14)B flakes with a thickness below 100 nm and an aspect ratio as high as 10(2)-10(3) and anisotropic square nanoparticles with a size of 11 nm. Both the nanoparticles and nanoflakes showed a strong [001] out-of-plane texture. The nanoparticles showed a spin reorientation temperature which is lower (117 K) than the bulk value (135 K). The successful fabrication of Nd-Fe-B nano-thin flakes and anisotropic nanoparticles provides hope for the development of nanocomposite permanent magnets with an enhanced energy product.

Recent advances in additive manufacturing made it feasible to fabricate products with desired shapes and features. Herein, a new, photocurable 3D printer ink mainly based on pentaerythritol triacrylate (PETA) is reported. To achieve rapid curing needed for 3D printing process, high performance water‐soluble photoinitiator, lithium phenyl‐2,4,6‐trimethylbenzoylphosphinate (LAP), was emulsified in PETA monomers and this suspension was evaluated for its polymerization kinetics by exposing to 395 nm UV‐light. The distinct influences of LAP and triethanolamine (TEA) concentrations on photo‐polymerization and printability were examined and an optimum concentration for extrusion‐based 3D printing was found to be 10 mM and 1.62 M for LAP and TEA, respectively. Synthesized PETA‐based 3D printer ink was functionalized by dispersing magnetic particles/flakes into the mixture, and consequently, a magneto responsive ink was obtained to be used in specialized applications. A ring‐shaped structure embedded with micron sized iron flakes was printed as a prototype. This study presents a versatile photo‐curable polymer formulation with possible translation to high performance 3D printing of customizable shapes that can be utilized in a wide range of areas such as micro‐robotics and medical science.

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