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|Surface:||Bright||Coil Weight:||1-5 Kg|
|Magnetic Properties:||2 Class|
Ohmalloy-1J79 widely used in radio-electronic industry, precision instruments, remote control and automatic control system.
It is a nickel–iron magnetic alloy, with about 80% nickel and 20% iron content. Invented in 1914 by physicist Gustav Elmen at Bell Telephone Laboratories, it is notable for its very high magnetic permeability, which makes it useful as a magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields. Commercial permalloy alloys typically have relative permeability of around 100,000, compared to several thousand for ordinary steel.
In addition to high permeability, its other magnetic properties are low coercivity, near zero magnetostriction, and significant anisotropic magnetoresistance. The low magnetostriction is critical for industrial applications, allowing it to be used in thin films where variable stresses would otherwise cause a ruinously large variation in magnetic properties. Permalloy's electrical resistivity can vary as much as 5% depending on the strength and the direction of an applied magnetic field. Permalloys typically have the face centered cubic crystal structure with a lattice constant of approximately 0.355 nm in the vicinity of a nickel concentration of 80%. A disadvantage of permalloy is that it is not very ductile or workable, so applications requiring elaborate shapes, such as magnetic shields, are made of other high permeability alloys such as mu metal. Permalloy is used in transformer laminations and magnetic recording heads.
|Yield strength||Tensile Strength||Elongation|
|Electrical resistivity at 20℃(Ωmm2/m)||0.55|
|Coefficient of linear expansion(20℃~200℃)X10-6/℃||10.3~11.5|
|Saturation magnetostriction coefficient λθ/ 10-6||2.0|
|Curie point Tc/ ℃||450|
The magnetic properties of alloys with high permeability in weak fields
|1J79||Initial permeability||Maximum permeability||Coercivity||Saturation magnetic induction intensity|
Сold-rolled strip/ sheet.
|μ0.08/ (mH/m)||μm/ (mH/m)||Hc/ (A/m)||BS/ T|
|cold drawn wire|
|Mode of heat treatment 1J79|
|Annealing media||Vacuum with a residual pressure not higher than 0.1Pa, hydrogen with a dew point of not higher than minus 40 ℃.|
|The heating temperature and rate||1100~1150℃|
|Cooling rate||With 100 ~ 200 ℃/ h cooled to 600 ℃, rapidly cooled to 300℃|