Permalloy 1J85 Alloy (marketing department of Shanghai HY Industry Co., Ltd)
1J85 is a nickel-iron magnetic alloy with a nickel content of approximately 80% and an iron content of approximately 20%. Invented by Bell Telephone Laboratories physicist Gustav Elmen in 1914, it is known for its very high magnetic permeability, which makes it useful as a magnetic core material for electrical and electronic equipment, and as a magnetic shield against magnetic fields shield. Commercial permalloy typically has a relative permeability of around 100,000, compared to the thousands for common steel.
In addition to high magnetic permeability, its other magnetic properties are low coercivity, near zero magnetostriction, and pronounced anisotropic magnetoresistance. Low magnetostriction is critical for industrial applications, enabling its use in thin films where variable stress would otherwise cause devastatingly large changes in magnetism. The electrical resistivity of permalloy can vary by as much as 5%, depending on the strength and direction of the applied magnetic field. Permalloy generally has a face-centered cubic crystal structure with a lattice constant of about 0.355 nm around an 80% nickel concentration. A disadvantage of permalloy is that it is not very ductile or machinable, so applications that require fine shapes, such as magnetic shielding, are made from other high permeability alloys such as permalloy for transformer laminations and magnetic recording head.
As a typical soft magnetic Permalloy, 1J85 has high initial permeability μ0 and maximum permeability μm, high saturation magnetic induction Bs and low coercive force Hc under weak magnetic field, and the structure is stable, The magnetic properties are less sensitive to external disturbance factors. This type of alloy is mainly used for magnetic head cores, magnetic conductors, magnetic shields, shells of recording heads, magnetic chips, sensors, etc. working under weak AC magnetic fields.
With the continuous development of aerospace engineering and electronics industry, the quality requirements for soft magnetic alloys, especially high-nickel soft magnetic alloys, are also increasing. 1J85 Permalloy is a high-nickel soft magnetic alloy with high initial magnetic permeability, which is widely used in the electronic information industry.
Chemical Composition of Permalloy 1J85
Material Grade |
Executive standard |
Chemical Composition(%) |
|||||||||||
C |
S |
P |
Mn |
Si |
Ni |
Cr |
Co |
Mo |
Cu |
Al |
Fe |
||
MAX |
|||||||||||||
1J85/Super-permalloy |
0.03 |
0.02 |
0.02 |
0.-3-0.6 |
0.15-0.30 |
79-81 |
– |
– |
4.8-5.2 |
≤0.2 |
– |
余 Bla. |
Heat Treatment Process of Permalloy 1J85
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The chemical composition of the alloy has an influence on the heat treatment process, and better magnetic properties can be obtained by adjusting the heat treatment process.
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Within 1200 ℃, with the increase of annealing temperature, it is beneficial to improve the magnetic properties.
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When the annealing holding time is less than 4h, the holding time can be extended appropriately to improve the magnetic properties. The holding time can be appropriately shortened when the annealing temperature is increased.
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The two-step process is also a reasonable process.
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Based on the production cost and the above analysis, the optimal heat treatment process for the 1J85 alloy produced by the Provincial Iron and Steel Research Institute is: heating up to 1150 °C with the furnace, holding for 4 hours, then slowly cooling to 600 °C, and finally at a rate of more than 500 °C/h Rapid cooling to 300 ℃ out of the oven.
About Permalloy 1J85 Smelting Suggestions
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Increase the time of smelting and refining during the smelting process to make the alloy composition as homogeneous as possible. For different smelting furnaces, summarize and count the alloy yield, the source of inclusions and the amount of inclusions, so that each Alloy composition control methods available for furnaces.
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Alloy cold-rolled thin strips are annealed in a hydrogen atmosphere at high temperature (1300°C) for a long time. After heat preservation, the cooling rate is controlled to about 300°C and air-cooled, and the cooling rate is precisely controlled. It is possible to increase the high temperature annealing time and adopt a heat treatment system of 500°C secondary intermediate temperature annealing and then rapid cooling. Shock, vibration and other forces should be avoided during use.
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Use reasonable smelting, refining and heat treatment processes to control the grain size and grain size of the alloy, such as increasing the annealing temperature during heat treatment, extending the holding time during annealing, and adopting two-stage continuous annealing.
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In the later stage of smelting, in addition to adding Si and alloys with adjusted composition, it is also recommended to add alloys containing Ca and Ba, which is beneficial to the accumulation and floating of inclusions. The floating inclusions are removed to increase the purity of the alloy. The object size is far away from the magnetic domain wall size of about 1 μm, which reduces the influence on the rotation and movement of the magnetic domain wall, thereby increasing the magnetic performance.