title: Big Area Additive Manufacturing of High Performance Bonded NdFeB Magnets.
abstract: Additive manufacturing allows for the production of complex parts with minimum material waste, offering an effective technique for fabricating permanent magnets which frequently involve critical rare earth elements. In this report, we demonstrate a novel method - Big Area Additive Manufacturing (BAAM) - to fabricate isotropic near-net-shape NdFeB bonded magnets with magnetic and mechanical properties comparable or better than those of traditional injection molded magnets. The starting polymer magnet composite pellets consist of 65 vol% isotropic NdFeB powder and 35 vol% polyamide (Nylon-12). The density of the final BAAM magnet product reached 4.8 g/cm3, and the room temperature magnetic properties are: intrinsic coercivity Hci= 688.4 kA/m, remanence Br= 0.51 T, and energy product (BH)max= 43.49 kJ/m3(5.47 MGOe). In addition, tensile tests performed on four dog-bone shaped specimens yielded an average ultimate tensile strength of 6.60 MPa and an average failure strain of 4.18%. Scanning electron microscopy images of the fracture surfaces indicate that the failure is primarily related to the debonding of the magnetic particles from the polymer binder. The present method significantly simplifies manufacturing of near-net-shape bonded magnets, enables efficient use of rare earth elements thus contributing towards enriching the supply of critical materials.
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Ling
authors: L
authors: Li
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Angelica
authors: A
authors: Tirado
authors: Ames Laboratory, Ames, Iowa 50011, USA.
authors: I C
authors: IC
authors: Nlebedim
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Orlando
authors: O
authors: Rios
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Brian
authors: B
authors: Post
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Vlastimil
authors: V
authors: Kunc
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: R R
authors: RR
authors: Lowden
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Edgar
authors: E
authors: Lara-Curzio
authors: Magnet Applications, Inc., DuBois, PA 15801, USA.
authors: Robert
authors: R
authors: Fredette
authors: Magnet Applications, Inc., DuBois, PA 15801, USA.
authors: John
authors: J
authors: Ormerod
authors: Ames Laboratory, Ames, Iowa 50011, USA.
authors: Thomas A
authors: TA
authors: Lograsso
authors: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: M Parans
authors: MP
authors: Paranthaman