FeCrCo & Crovac, Iron Chrome Cobalt Magnets – Overview

Iron Chrome Cobalt magnets / FeCrCo Magnets have something similar with Alnico Magnet on production and characteristic. FeCrCo Magnets also have high remanence but low Hc which is similar with Alnico 5 Magnets, They also have high working temperature and very low-temperature coefficient of Br which is also similar with Alnico Magnets. They are also made magnetism by a process of heat treatment, and they also classified to the isotropic and anisotropic material by the process of magnetic orientation. It can be made as different shapes and sizes such as wire, tube, bar, strip etc.

The very difference of FeCrCo Magnets is they are very machinable. As all know, whether Alnico Magnets or Rare earth magnetic materials, they are all brittle, they are only able to be machined by limited methods, For example, grinding and linear cutting. But FeCrCo Magnets can be machined by lots of methods prior to the heat treatment.

Characteristic of FeCrCo Magnets
Machinable prior to the heat treatment
High working temperature.
Low-temperature coefficient; Very Temperature stable.
Various shapes. they can be produced to very thin and very small part.
low Hc

They are a replacement for CuNiFe magnetic material (CuNiFe is not commercially available any more).

Advantages

• Malleable – FeCrCo is easier to machine than Alnico
• FeCrCo can be hot deformed
• The maximum recommended operating temperature is typically around +400 degrees C (752F)
• FeCrCo has a Hc varying typically from 50kA/m to 300kA/m. The value of Hc produced depends on the method of the final heat treatment (timescale, temperature and quench rate)
• FeCrCo usually does not require any corrosion coating

Disadvantages

• If the final heat treatment is not performed, the magnetic performance is very poor
• The strips are usually thin. Thicker sheets and plate are not really possible
• Easily demagnetised or remagnetised in a different direction

Typical Applications

• Compasses
• Hysteresis coupling applications e.g. a multi-pole permanent magnet rotor turning a FeCrCo disc by hysteresis

Example

A company wanted a customised needle for a compass they were designing.
The needle could be produced to the shape, heat treated, painted and magnetised to their requirements.

FeCrCo Crovac

Iron chromium Cobalt (FeCrCo) magnets are similar to Alnico magnets in magnetic property, but they have better mechanical property. FeCrCo alloys can be easily hot deformed and machined. There are practically no limitations of their shapes and sizes. They can be made to block, square rods, round rods, tube, strips, wire. FeCrCo magnets are beneficial combination of magnets and mechanical properties. Their maximum working trmperature can be as high as 400°C.

Fecrco Magnet Usage
Fe – Cr – Spinodal decomposition Co alloy is according to the theory of Fe – in the alloy based on binary Cr plus Co, FeCrCo magnet in high form a single alpha, then, through the Spinodal decomposition form alpha 1 and 2, then the alpha tempering process, two phase composition difference, thus can achieve higher magnetic.

TYPICAL MAGNETIC PROPETIES OF IRON-CHROMIUM-COBALT MAGNETS
(US STANDARD)
GRADE
RESIDUAL INDUCTION(BR)
COERCIVE FORCE(HCB)
(BH)MAX
MARK
Br:Residual induction /Hcb:Coersive Force /Hcj:intrinsic Coersive Force /(BH)max:Max Energy Product
kGs(mT)
kA/m(kOe)
kJ/M3(MGOe)
Fe Cr Co 1
8.8(880)
37(0.46)
12.7(1.60)
Isotropic
Fe Cr Co 2
9.9(990)
28(0.35)
12.7(1.60)
Isotropic
Fe Cr Co
10.5(1050)
16(200)
8.0(1.00)
Isotropic
Fe Cr Co 1
9.0(900)
39(490)
13.0(1.63)
Isotropic
Fe Cr Co 5
13.5(1350)
48(600)
41.8(5.25)
anisotropic
Fe Cr Co 250
14.0(1400)
20(250)
15.9(2.00)
anisotropic
Fe Cr Co 640
12.0(1200)
51(641)
35.0(4.4)
anisotropic
TYPICAL MAGNETIC PROPETIES OF IRON-CHROMIUM-COBALT MAGNETS
(CN STANDARD)
GRADE
RESIDUAL INDUCTION(BR)
COERCIVE FORCE(HCB)
COERCIVE FORCE(HCJ)
(BH)MAX
MARK
Br:Residual induction /Hcb:Coersive Force /Hcj:intrinsic Coersive Force /(BH)max:Max Energy Product
kGs(mT)
kA/m(kOe)
kA/m(kOe)
kJ/M3(MGOe)
FeCrCo10/3
820(8.2)
340(27)
360(29)
10(1.25)
Isotropic
FeCrCo12/4
800(8.0)
500(40)
530(42)
12(1.5)
Isotropic
FeCrCo28/5
1000(10)
570(45)
580(46)
28(3.5)
anisotropic
FeCrCo30/4
1150(11.5)
500(40)
510(41)
30(3.8)
anisotropic
FeCrCo35/5
1050(10.5)
630(50)
640(51)
35(4.4)
anisotropic
FeCrCo36/5
1200(12.0)
660(52)
680(54)
36(4.5)
anisotropic
FeCrCo44/4
1300(13.0)
560(44)
570(45)
44(5.5)
anisotropic
FeCrCo52/5
1350(13.5)
600(48)
620(49)
52(6.5)
anisotropic
Feature:

Fe-Cr-Co alloy has a big advantage, namely its high Curie temperature, Tc = 680ºC for the left and right (Tc slightly different in different alloy grades) so that its temperature can reach 400ºC, reversible temperature coefficient is small, is -0.0128%ºC, the magnetic stability of the well for the high-precision components.

FeCrCo Characteristics:

FeCrCo Can be made to small and complex shape components. Its minimum diameter can reach 0.05mm and the thinnest thickness can reach 0.1mm, so it is suitable for the production of high-precision components. It has good temperature stability and corrosion resistance. The high Curie temperature is about 680℃ and the highest wroking teperature can reach 400℃ .

Iron-Chrome-Cobalt permanent magnets are a malleable, magnetically semi-hard alloy which is available in cast form (see the Alnico Magnet section) and as thin rolled strip,bar,rod or wire from Rolled Products facility. It is an excellent material for hysteresis coupling and for sensor applications. It is also a substitute for CuNiFe, which is no longer commercially available.

As the Fe-Cr-Co alloy has excellent mechanical properties and magnetic properties, determined that it is widely used in various fields.Years of production in our many thousands of customers Tigong the specification of components, Baokuo heaven Fei Ji, rockets, land of guns, tanks, cars, underwater in the submarine, the vessel Hai Shang Deng, Du Guo Women use the magnetic components.Now, with the technological level of the increase, the States development and growth, on magnetic materials in the application of products for civilian use has expanded and a large amount of Xiangdang in the instrumentation industry, Yonglaizhizao magnetic materials ammeter, voltmeter, tachometer, electric degreestable galvanometer, the oil level gauge, etc.; in the electronics and telecommunications industry used to produce hysteresis motor, micro motor, computer Embroidery Machine; phone buzzer; for travel goods, clothing decoration, stationery, etc.compass.In the aviation and maritime areas: for the magnetic compass, gyro, etc., also used in various household appliances such as stereo speakers; TV, hearing aids, electromagnetic locks, alarm, etc..Medical, in addition to manufacturing medical devices, the magnetic health-care equipment such as magnetic glasses, magnetic shoe, magnetized water, etc. are also widely used.Another is also a great demand for petroleum exploration.

LECMAG’s FeCrCo & Crovac (Iron Chrome Cobalt Magnets) Display

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