TY - JOUR
T1 - Influence of powder loading fraction on properties of bonded permanent magnets prepared by selective laser sintering
AU - Mapley, Martin
AU - Gregory, Shaun D.
AU - Pauls, Jo P.
AU - Tansley, Geoff
AU - Busch, Andrew
N1 - Funding Information:
This work was supported by the Prince Charles Hospital Foundation, Brisbane, Australia [NI2017–28, TM2017-04]. J.P.P. was supported by a Fellowship (RF2018-04) from The Prince Charles Hospital Foundation, Brisbane, Australia. S.D.G. was supported by a Fellowship (102062) from the National Heart Foundation of Australia.
Publisher Copyright:
© Copyright 2021, Mary Ann Liebert, Inc., publishers 2021.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/6
Y1 - 2021/6
N2 - Production of bonded permanent magnets (PMs) by processing a mixture of neodymium-iron-boron (Nd-Fe-B) (spherical and flake) and polyamide-12 powders using selective laser sintering (SLS) has focused on increasing the magnetic powder loading fraction to improve the magnetic performance of PMs. However, when using SLS to produce PMs from mixed feedstock, the likelihood of the areas between the magnetic particles being infiltrated by the liquefied binder inducing particle bonding is reduced as binder content is reduced. This decreases mechanical strength and introduces upper limits to the attainable loading fraction of the magnetic powder. The present study investigated the mechanical properties and provided an insight into the residual induction, of loading fractions between 10% and 90% of spherical and flake powders when producing PMs using SLS. The maximum attainable loading fractions were 80%/vol and 70%/vol for the flake and spherical powders, respectively. The PMs produced from the flakes reached a maximum density and residual induction at 50%/vol loading fraction. The PMs produced from spherical powder reached maximum density and residual induction at 70%/vol loading fraction; however, a knee point at 30%/vol loading fraction demonstrated only minor improvements to density (8.8%) and residual induction (13.4%) with further increases in loading fraction. Although PMs produced from flakes demonstrated superior mechanical properties, the elastic modulus and strain limit rapidly decreased with increases in powder loading fraction for both powder types. This study demonstrated the application-specific balance between mechanical and magnetic strength that must be considered when producing PMs by using SLS.
AB - Production of bonded permanent magnets (PMs) by processing a mixture of neodymium-iron-boron (Nd-Fe-B) (spherical and flake) and polyamide-12 powders using selective laser sintering (SLS) has focused on increasing the magnetic powder loading fraction to improve the magnetic performance of PMs. However, when using SLS to produce PMs from mixed feedstock, the likelihood of the areas between the magnetic particles being infiltrated by the liquefied binder inducing particle bonding is reduced as binder content is reduced. This decreases mechanical strength and introduces upper limits to the attainable loading fraction of the magnetic powder. The present study investigated the mechanical properties and provided an insight into the residual induction, of loading fractions between 10% and 90% of spherical and flake powders when producing PMs using SLS. The maximum attainable loading fractions were 80%/vol and 70%/vol for the flake and spherical powders, respectively. The PMs produced from the flakes reached a maximum density and residual induction at 50%/vol loading fraction. The PMs produced from spherical powder reached maximum density and residual induction at 70%/vol loading fraction; however, a knee point at 30%/vol loading fraction demonstrated only minor improvements to density (8.8%) and residual induction (13.4%) with further increases in loading fraction. Although PMs produced from flakes demonstrated superior mechanical properties, the elastic modulus and strain limit rapidly decreased with increases in powder loading fraction for both powder types. This study demonstrated the application-specific balance between mechanical and magnetic strength that must be considered when producing PMs by using SLS.
KW - additive manufacturing
KW - functional materials
KW - hard magnetic materials
KW - polymers
UR - http://www.scopus.com/inward/record.url?scp=85107774600&partnerID=8YFLogxK
U2 - 10.1089/3dp.2020.0297
DO - 10.1089/3dp.2020.0297
M3 - Article
AN - SCOPUS:85107774600
SN - 2329-7662
VL - 8
SP - 169
EP - 175
JO - 3D Printing and Additive Manufacturing
JF - 3D Printing and Additive Manufacturing
IS - 3
ER -