Professor Thomas Schreflat is leading a team St. Pölten University of Applied Sciences in Austria showing that rare earth permanent magnets may contain local deformations in the crystal lattice of the material, resulting in a weakening of the magnetic force of the material in those areas.  Finding ways to minimize or eliminate the deformations would lead to using less rare earth materials in manufacturing magnets.

The rare earth elements are an expensive and necessary component of strong permanent magnets.  Annual production is at 150,000 metric tons, suggesting the rare earths are really not that rare. The problem is that they are particularly difficult to extract due to the low concentrations.  Thus the concentration level for mines is what garners the most attention.

In view of rapidly growing global demand, a shortage is therefore imminent.

The St. Pölten University team can show with computer simulations strong permanent magnet manufacturing can be optimized and thereby reduce the rare earth elements needed and perhaps reduce the size.

The results, presented in the U. S. March 1st 2011 at the annual meeting of the US Minerals, Metals & Materials Society in San Diego, California, show the deformations are all located at the boundary of grains within the material. According to the calculations of the St. Pölten University team, the magnetic force of the material is weakened in these areas. Thus costs could be reduced by optimizing the material structure – that saves resources by reducing the amount of rare earths required.

The St. Pölten University team studied the exact structure of neodymium magnets. In addition to the rare earth element neodymium, the magnets consist of iron and boron.  Prof. Schrefl, head of the Industrial Simulations study course commented on the recent findings explaining, “Our simulations show disturbances in the crystalline structure in neodymium magnets. Such disturbances cause the magnetizing direction to change in these areas. In a so-called anisotropic magnet, like the neodymium magnet, in which all parts must have the same magnetizing direction, this phenomenon weakens the magnet.”

Neodymium Iron Boron Magnet Grain Junction Illustration. Image Credit: Thomas Schrefl. Click image for the largest view.

Here’s the key of the matter: The team’s simulations show that such disturbances in the junctions between individual material grains occur when three different grains meet. In these triple junctions, a non-magnetic enclosure is formed and the crystal lattice near the enclosure is disturbed. In the same region, a high demagnetising field weakens the magnet further.  This is to say when a magnet is built the deformations at the grain junctions sets up a small magnet working against or canceling a part of the whole magnet.

Obviously that’s not good.

The influence of disturbances on the magnet’s behavior was found in multiscale simulations that take into account several different dimensions: from the atomic to the visible range. Conventional simulations were unable to cover this range of sizes until now. It was the combination of individual numerical computational methods, such as fast boundary element methods and tensor grid methods for computing the magnetic fields, which finally made it possible. The development credit goes to Prof. Schrefl’s team as part of the Special Research Program ViCoM – Vienna Computational Materials Laboratory.

Prof. Georg Kresse the spokesperson for the Special Research Program at the research group Computational Materials Physics at the University of Vienna, explained the aims of the Special Research Program: “We want to describe the correlated movement of electrons more accurately. This electron correlation is mainly responsible for the cohesion of solid-state bodies and molecules. An accurate description is therefore crucial for precisely predicting the mechanical, electronic and optical properties of materials.”

The Special Research Program helps with the optimization of magnetic and magneto-optical storage, as in high-performance permanent magnets for electric cars or wind turbines, thereby making a substantial contribution to developing future-oriented technologies.  The magnet group is only one of in a total of twelve project groups with more than 50 scientists working on describing material properties.  Other industrial targets for improvement are microelectronics, solar technology, polymer production and numerous other technologies.

Knowing the deformation junction should allow process designers and engineers to start finding the ways to build magnets using less material.  The development might include new element recipes, processes and /or other refinements.

How much can be gained is a noticeable question.  From catalogs of magnets its clear that in the rare earth based market there is quite a range of power by weight – indicating that improvements should come as the research moves from the simulation to application.

Improvements won’t be obvious to consumers, but engineers knowing the power robbing junctions are there offers new room with a better foundation for more ideas on how to gain power from the elements and space allowed for magnets, which should offer consumers better and lower cost goods in the coming years.


2 Comments so far

  1. paul christensen on March 9, 2011 11:17 PM

    i have samples which i think it may be hydrogen 3 next generation fuel i am looking for some 1 to analysis it also material which was in the spaceship that crashed in the USA there is 8 elements have 4 two 2 dig up this summer looking for the 7 th 1 i need some 1 who can test for the unknown is there any 1 out that can help me

  2. paul christensen on March 9, 2011 11:21 PM

    8 element is sulphur

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