Magnetic additives

However, magnetic additives such as ferrites or rare earths can be added to plastics to produce polymer magnets. 

The two main families of magnetic additives used for polymer magnets are ferrites and rare earths, which have very different characteristics. 

Table 3.24 contains general information on magnetic additives for PVC Table 3.24. PVC magnetic additives.

As for the cemented coating constitution, the carbon stability in iron is very low. This addition element is essentially present under the form of cementite. The presence of carbon atoms in iron leads to an increasing of the resistivity and diminishes the magnetic permeability. 

The different techniques of NDT were applied to evaluate the method allowing to give an optimal spectrum so that the interpretation can be done easily. In addition, and for the purpose of the defects quantification, we have done an optimization on the magnetic powders, colored and fluorescent, by applying magnetic powders of variable dimensions. This will enable us to estimate defects with a high precision. 

The obtained results for the magnetic bench have allowed to note that defects situated at 12 mm of depth have been observed clearly. This is explained by the high power furnished by the bench, in addition its induction is double alternation rectified. Dimensions of the defect (height and width) are precisely estimated (figure 1). The defect detection at this depth is due to the application of a rectified field, so skin phenomenon is almost absent. 

The curve allows determining the comer of a magnetic moment of one magnet (region 16 -i- 70 ). The comer of a magnetic moment of the second magnet is found as additional for comer proportional to (in + l)l80 , where n = 0,1, 2. Being calculated, this dependence is written as follows h... 

In addition, there could be a mechanical or electromagnetic interaction of a system with an external entity which may do work on an otherwise isolated system. Such a contact with a work source can be represented by the Hamiltonian U p, q, x) where x is the coordinate (for example, the position of a piston in a box containing a gas, or the magnetic moment if an external magnetic field is present, or the electric dipole moment in the presence of an external electric field) describing the interaction between the system and the external work source. Then the force, canonically conjugate to x, which the system exerts on the outside world is... 

The little atomic magnets are of course quantum mechanical, but Weiss s original theory of paramagnetism and ferromagnetism (1907) [7] predated even the Boln atom. He assumed that in addition to the external magnetic field Bq, there was an additional internal molecular field B. proportional to the overall magnetization M of the sample. 

Furthennore, the magnetic diffraction and the nuclear diffraction do not interfere with one another, and the nuclear and magnetic intensities simply add together, although in many cases the magnetic unit cell is larger than the nuclear unit cell, which produces additional diffraction peaks. 

Higher magnetic fields exist tiian those used in NMR but the NMR experiment imposes constraints in addition to just magnitude. An NMR spectroscopy experiment also demands homogeneity and stability of the magnetic... 

Motion, and in particular diffiision, causes a further limit to resolution [14,15]. First, there is a physical limitation caused by spins diflfiising into adjacent voxels durmg the acquisition of a transient. For water containing samples at room temperature the optimal resolution on these grounds is about 5 pm. However, as will be seen in subsequent sections, difhision of nuclei in a magnetic field gradient causes an additional... 

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