The following is straight from the Simens website:-
Hooked on Rare Earths. The core of the problem is the fact that rare-earth metals are required for many high-tech products, including electric motors, cell phones, laser devices, and LCD television sets. And the introduction of energy-saving light bulbs, whose fluorescent materials also require rare-earth elements, has further increased demand. “The excellent properties of rare-earth elements have led to development of new products, which have boosted the market further,” explains Dr. Ulrich Bast, who is in charge of Technology Innovation at CT in Munich.
Electric motors, for instance, can operate either with two-coil magnets or with one coil and one permanent magnet. Synchronous machines equipped with permanent magnets are a separate class of motors and generators. They can substantially reduce the weight of wind turbines. “Use of conventional materials, such as iron and copper, results in a heavy machine,” says Dr. Gotthard Rieger, who heads Magnetic Materials Development at CT. A much more elegant solution would be to equip the external rotors, which “tap” the rotational energy of such a turbine, with thin neodymium-iron-boron magnets that induce an electrical field in the coils. In conventionally- designed wind energy systems, a massive gear set converts relatively slow rotation into fast rotation, which then generates electric power in the generator. New versions, however, are designed to use permanent magnets based on rare-earth elements to generate power directly from the slow rotation. The advantages are that no gear set is needed, weight is reduced, and less maintenance is required, which is an advantage in offshore applications. Siemens already offers gearless turbines in 3-megawatt and 6-megawatt systems.
What this means is that demand for rare-earth elements will continue to increase. What’s more, China is going to play a steadily expanding role in wind turbines and electric vehicles, so it will consume more of its own resources. Siemens is addressing this challenge in the context of an advanced project. For instance, researchers led by Thomas Scheiter are conducting an analysis of the key materials the company uses and in what quantities. They will then analyze current market data to determine whether there are raw materials whose use should be considered critical with regard to their availability.
If the answer is affirmative, the roughly 200 materials scientists at CT will face the task of developing alternatives. Given the impending shortage of rare-earth elements, the company has launched a project designed to develop new kinds of powerful permanent magnets. Such magnets will have to be produced either without any rare-earth elements or with only very small amounts of them.
“In order to use dysprosium more efficiently than has been done in the past, for example, we are no longer going to distribute it throughout all the material in a magnet,” says Rieger. “Instead, we will create a structure in which this element is concentrated only along the crystallite boundaries within the neodymium-iron-boron part of each magnet.” This can be achieved by applying a thin dysprosium layer on the finished magnet, and then using a heat treatment to diffuse it along the grain boundary into the interior. This approach drastically reduces dysprosium use, while leaving needed properties unchanged or even improving them.
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