Bonded NdFeB magnets are composed of a special form of NdFeB powder with a plastic carrier material. They have lower energy product than Sintered NdFeB magnets. Very complicate shapes can be produced in Bonded NdFeB magnets with very close dimensions.
Manufacturing Process
Bonded NdFeB magnets is produced by a special form of NdFeB powder blended with a plastic carrier material, die pressed and then heated. Parts made in this way can be of complex shapes and come off the tool with close tolerances, requiring no further finish machining.
Machining
Bonded NdFeB magnets is easily machined. Coolants must be used while machining this material in order to avoid spontaneous combustion of powder. Machining this material removes a layer of protective coating, and re-coating for corrosion resistance may be necessary.
Surface treatments
The corrosion resistance of Bonded NdFeB magnets is considered poor, epoxy coating is mostly common used for bonded NdFeB magnets.
Magnetizing
Bonded NdFeB materials are isotropic and can be magnetized in any direction or with multiple poles. Special magnetizing fixtures are required in order to achieve multiple pole magnetization, depending on complexity of design and production rate requirements.
Physical properties of Bonded NdFeB magnets
Grade Density Permeability Temperature Coefficient of Br Temperature Coefficient of Hc
BNP-3 5.8-6.5g/cm3 1.30μ r -0.11α(Br) %/ ℃ -0.14α(Hc) %/ ℃
BNP-6 5.8-6.3g/cm3 1.30μ r -0.11α(Br) %/ ℃ -0.14α(Hc) %/ ℃
BNP-8 5.8-6.2g/cm3 1.20μ r -0.11α(Br) %/ ℃ -0.14α(Hc) %/ ℃
BNP-8SR 5.8-6.2g/cm3 1.16μ r -0.07α(Br) %/ ℃ -0.09α(Hc) %/ ℃
BNP-9H 5.8-6.2g/cm3 1.16μ r -0.07α(Br) %/ ℃ -0.09α(Hc) %/ ℃
BNP-10 5.8-6.2g/cm3 1.20μ r -0.11α(Br) %/ ℃ -0.11α(Hc) %/ ℃
BNP-11 5.8-6.2g/cm3 1.20μ r -0.11α(Br) %/ ℃ -0.11α(Hc) %/ ℃
BNP-12L 5.8-6.2g/cm3 1.20μ r -0.08α(Br) %/ ℃ -0.26α(Hc) %/ ℃