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Q: |
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What P/M materials are available
from Hoeganaes for electromagnetic applications? |
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A: |
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There are two families of
materials for electromagnetic applications. The first are powders used in the sintered
state. These materials include pure irons such as Ancorsteel 1000, Ancorsteel 1000B and
Ancorsteel 1000C, iron-phosphorous alloys such as Ancorsteel 45P and Ancorsteel 80P,
iron-silicon alloys with silicon contents varying typically up to 6% and ferritic
stainless steel powders such Ancor 410L, Ancor 430, and Ancor 434. The second family of
powders are the Ancorsteel Insulated powders. |
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Q: |
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What differentiates the two
families of powders and their application? |
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The first materials are compacted
to net-shape and sintered to obtain optimal mechanical and magnetic properties. Since
these materials are utilized in their sintered state and are essentially large pieces of
ferrous materials, they are typically used in applications where high permeability values
and low coercive force values are required and the presence of rapidly alternating
magnetic fields are kept to minimum (DC applications).
Ancorsteel Insulated powders are designed
for electromagnetic applications requiring constant magnetic permeability and low core
losses over a wider range of operating frequencies (AC applications). For this material,
each powder particle is insulated from the each other prior to the compaction step. The
insulation is made up of either a combination of an oxide coating with a thermoplastic
coating or a single thermoplastic coating. The materials are not sintered following
compaction resulting in a high resistivity component. Despite the fact that the materials
are not sintered, these highly engineered materials result in parts with tensile strengths
in excess of 15,000 psi. |
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Q: |
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What are typical magnetic
properties of these materials? |
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A: |
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Like all P/M materials, the
magnetic properties of these materials can be easily modified to meet specific application
requirements. The chemistry, density and processing of the component can provide a wide
range of magnetic and physical properties. The following tables outline the range of
performance possible. |
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Typical Magnetic
Properties for Sintered (DC) Materials Measured at a Maximum Drive Field of 15 Oe
| Alloy System |
Typical Density
(g/cm³) |
Maximum
Permeability |
Coercive Force (Oe) |
Maximum Induction
(kGauss) |
Resistivity
(µohm-cm) |
| Iron |
6.8-7.2 |
1,800 / 3,500 |
1.5 / 2.5 |
10 / 13 |
10 |
| Fe-P |
6.7-7.4 |
2,500 / 6,000 |
1.2 / 2.0 |
10 / 14 |
30 |
| Fe-Si |
6.8-7.5 |
2,000 / 5,000 |
0.6 / 1.2 |
9 / 14 |
60 |
| Ferritic Stainless
Steels |
5.9-7.2 |
5,00 / 1,500 |
2.0 / 4.0 |
6 / 8 |
50 |
| 50Ni / 50 Fe |
7.2-7.6 |
5,000 / 15,000 |
0.2 / 0.5 |
9 / 12 |
45 |
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Q: |
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What are typical applications for
the insulated particle material? |
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A: |
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Typical applications are for AC
applications that have an operating frequency above 300Hz. Below this operating frequency
the lower permeability of the insulated materials will give inferior performance to
laminations. |
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Q: |
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Can IP be used in DC applications? |
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Yes, but the application will be
better served by a sintered material. The reduced permeability for IP is just not a good
match. |
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Q: |
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What effects sintered magnetic
properties? |
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A: |
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Several material and processing
parameters effect magnetic performance of P/M materials. As density increases, the
magnetic properties of maximum induction and permeability are increased significantly. The
addition of certain alloying elements such as P and Si, improve the nearly all magnetic
properties. In particular, these alloying elements tend to increase resistivity while
decreasing (improving) coercive force. The presence of the interstitial elements, carbon
and nitrogen, have a very potent detrimental effect on magnetic performance. Elevated
levels of these elements are usually found as the result of their presence in the
sintering atmosphere. Magnetic performance is also enhance by the use of higher sintering
temperatures. High temperature sintering results in higher density, more refined pore
structure and larger grain size, each which will improve magnetic performance. |