SIEMENS

Materials researchers at Siemens are on a high-speed treasure hunt. They know that just a handful of elements will suffice to open up a wide field of possible combinations. But they also know that speed is of the essence. Nuggets are rare and competitors are quick to capitalize on them. “Whoever is quickest gets the patent,” says Dr. Raquel de la Peña Alonso, who works at Siemens Corporate Technology (CT) in Munich, where she manages the High Throughput Experimentation (HTE) Lab. At the lab, robots that dose materials very precisely produce large numbers of samples. Special programs subsequently analyze the samples to measure their specific properties, such as their melting point or electrical conductivity. Because 120 samples are examined at the same time, the process is around 20 times faster than it would be if each substance were made by hand. That saves time, money, human resources, and material.

Powerful Illumination. The HTE Lab is developing new phosphors such as those found in white light-emitting diodes (LED), in which a blue light-emitting chip excites the covering phosphor in such a way that white light is produced. A phosphor’s strength and color depends on its composition and crystal structure. Together with Siemens subsidiary Osram, de la Peña Alonso is looking for phosphors that are more efficient or that produce colors other than those available today. Among other things, she and her team have discovered a phosphor whose light is redder than that of other materials. White LEDs need red light components in order to emit warm light. Thanks to de la Peña Alonso’s work, Osram now owns a few additional patents in the hotly contested LED market, and light-emitting diodes need less phosphor as a result.

Phosphors also contain rare earth elements such as europium. These materials may become scarce in the future as LEDs are increasingly used for general lighting. In view of this, CT has launched a research program that develops strategies for the sustainable use of these materials. Among the key issues being addressed here are permanent magnets containing the rare earth elements neodymium and dysprosium. These elements are used, for example, in wind turbines and electric motors — areas in which rapid growth could lead to supply bottlenecks. In view of this, CT’s Sustainable Materials research program, which is led by Dr. Thomas Scheiter, is examining new recycling techniques, researching magnetic materials that do without rare earth elements, and developing methods for assessing whether a product’s manufacture has minimized its use of raw materials.

Siemens is also managing a project funded by the German Ministry of Education and Research (BMBF) that is known as MORE, in which partners from research and industry are working together to find solutions for recycling electric motors. “Although the copper used in motors is widely recycled today, magnets are simply disposed of,” says Dr. Jens-Oliver Müller, who is responsible for the MORE project on Scheiter’s team. The researchers are therefore developing methods for dismantling motors and analyzing the quality of their magnets. Depending on their condition, magnets can either be immediately reused or melted down in order to make new ones. In addition, the project’s participants are working on chemical procedures for extracting rare earths directly from magnetic materials.

Since the summer of 2011, CT in Munich has also been developing the first permanent magnets that do not contain rare earths. Instead, the magnets consist of magnetic nano-sized rods made of a cobalt compound. Program director Dr. Gotthard Rieger is focusing on this material because it is more resistant to magnetization reversal than currently available aluminum-nickel-cobalt compounds. However, the material results in magnets that are not quite as stable as those made with rare earth elements. One way around this might be to make the magnets somewhat larger so that a weaker material could be used. “But achieving this will take time,” cautions Rieger, “as the materials not only need good magnetic properties, but also must be sufficiently thermally stable to be employed in electric cars. What’s more, we will also need manufacturing processes that will enable the material to be mass-produced.”

Other materials may also cause bottlenecks. “Indium and tungsten could soon be in short supply,” says Dr. Ute Liepold, a chemist at CT, who is working on a method for evaluating a product’s raw material efficiency. She wants to assess the materials contained in products according to three factors: their environmental impact, the reliability of their supply, and their importance for a product’s function. Such evaluations will be combined into an overall assessment, which could be used, for example, to compare a variety of electric motors and their magnets in terms of how efficiency their raw materials are used. Whereas the environmental impact of a range of materials could be assessed with the help of existing tools, standardized methods remain to be developed for the two other factors.

Complicated Mining Processes. No analysis of potential remedies to the scarcity of certain materials would be complete without taking mining into account. With this in mind, Siemens is working with the RWTH University in Aachen, Germany, and, by 2015, will invest €6 million to fund ten doctoral dissertations focusing on environmentally-friendly methods for mining rare earths. Mining these substances presents a challenge because they exist in nature only as mixtures of a variety of rare earth oxides. These oxides are extracted from ore chemically — using acids, for example — after which they are transformed into metals in a number of melting processes. The resulting slurries are potentially extremely harmful to the environment and have to be processed at great expense, which is why many mines closed down in the 1980s.

The partnership with the RWTH University was initiated by Prof. Dieter Wegener, head of the Advanced Technologies and Standards department at Siemens’ Industry Automation and Drive Technologies divisions. Wegener has developed a technique for evaluating “green” products and solutions with regard to their environmental impact and profitability.

In the context of a research project, Wegener’s team will for the first time depict the entire process chain from ore to finished magnets in an Eco-Care Matrix. “We will be looking for processes that perform better in the Matrix, since they would make it economically feasible to revitalize mines that have been taken out of service or exploit new deposits,” explains Wegener. This would be a big step toward reducing dependence on a handful of suppliers. According to Wegener, it would also make gearless wind turbines and electric motors even “greener” and more economical in terms of the Eco-Care Matrix.