Search results
Results from the WOW.Com Content Network
Carbonyl iron has lower losses than hydrogen-reduced iron, but also lower permeability. A popular application of carbonyl iron-based magnetic cores is in high-frequency and broadband inductors and transformers, especially higher power ones. Carbonyl iron cores are often called "RF cores".
Cobalt-iron alloys like permendur have very high Curie temperatures so they can function magnetically at high temperatures at which other ferromagnetic materials lose their magnetic properties. They are harder and less ductile than many other iron alloys and so are harder to fabricate, but have superior mechanical strength.
For example, 4% electrical steel has an initial relative permeability (at or near 0 T) of 2,000 and a maximum of 38,000 at T = 1 [5] [6] and different range of values at different percent of Si and manufacturing process, and, indeed, the relative permeability of any material at a sufficiently high field strength trends toward 1 (at magnetic ...
In 2009, a team of MIT physicists demonstrated that a lithium gas cooled to less than one kelvin can exhibit ferromagnetism. [12] The team cooled fermionic lithium-6 to less than 150 nK (150 billionths of one kelvin) using infrared laser cooling. This demonstration is the first time that ferromagnetism has been demonstrated in a gas.
Mu-metal has several compositions. One such composition is approximately 77% nickel, 16% iron, 5% copper, and 2% chromium or molybdenum. [1] [2]More recently, mu-metal is considered to be ASTM A753 Alloy 4 and is composed of approximately
Air and vacuum have high reluctance, while easily magnetized materials such as soft iron have low reluctance. The concentration of flux in low-reluctance materials forms strong temporary poles and causes mechanical forces that tend to move the materials towards regions of higher flux so it is always an attractive force (pull).
In the gaps G the electric field lines "bulge" out, so the field strength is less than in the core: B F < B B L – leakage flux; magnetic field lines which don't follow complete magnetic circuit L – average length of the magnetic circuit. It is the sum of the length L core in the iron core pieces and the length L gap in the air gaps G.
Hysteresis loop Induction B as function of field strength H for H varying between H min and H max; for ferromagnetic material the B has different values for H going up and down, therefore a plot of the function forms a loop instead of a curve joining two points; for perminvar type materials, the loop is a "rectangle" (Domain Structure of Perminvar Having a Rectangular Hysteresis Loop, Williams ...