Magnet emergency not enough! China Rare is the key

"We always look down on magnets, " Northwestern University in Boston developed a new type of magnetic material Laura Lewis (Laura Lewis) exclaimed , "People always think : ' Yes, yes, even to be used in the fridge magnets, how trivial it! '"

But in Lewis 's eyes, the story is completely different magnets . Permanent magnets is much more than a key component of the fridge , or high school experiment which is difficult to play with piles of metal , which can produce magnetic piece of metal itself is actually a lot of support from the core technology of our modern life .

These techniques included headphones from smart phones to personal items such as their slim shape thanks to the latest generation of highly efficient magnet for internal use , but far more than the magnet 's influence here . NY罗彻斯特阿Nordisk Magnetic Technologies Stephen Constantinides (Steve Constantinides) explains , " Our world runs on energy , automotive , turbines , computers , satellites, and a variety of transportation transport , which requires magnets. "

And now, a crisis is emerging . Gluttonous lust for power by the global stimulus , the demand for the best quality magnets are converging to an undercurrent torrent. The trouble is , we do not know where did you get so much talent magnet . Suddenly, Constantinides , Lewis , and their colleagues found that their work is under unprecedented attention .

To create a good magnet is not easy . 19th century, classical electromagnetic theory tells us that the charge motion generates a magnetic field , the magnetic field is a natural magnet in turn can drive charge . This discovery is enough to make a lot of iron , the most common natural magnetic material, the core of motors, generators and transformers such critical power technology . Core energy stored in these devices , the mechanical work and current into each other , is still true today .

But to explain such a permanent magnet produces a magnetic field and how to obtain the magnetic field and the ability to interact , you have to help a lot of 20th century physics job. All of this comes from the behavior of atoms in solid state electronics . The quantum theory and Einstein 's theory of relativity criteria used in these electronics, you will find that they behave like a small bar magnet that points either up or down , depending on the value of the electron spin .

In most materials , the number of electrons in each point of each half , so overall not exhibit magnetic effect , but some elements, such as iron, cobalt and nickel, as well as its neighbors in the periodic table , if all the outermost layer of atoms forming the bond is that participating in electron spin pointing parallel to each other , it will reduce the overall energy .

As long as these electronic firmly fixed that they are free to flip a solid lattice, then add a little magnetic field , the solid composition of these elements can generate its own magnetic field , and keep it consistent . In this way, you've got a permanent magnet.

Magnets around us everywhere, everyday communication , transportation, energy systems and even an important raw material , however, this is about not enough resources

Quality permanent magnet

Yes, this is a permanent magnet , but this is a good magnet it? "I have a need to meet the requirements of high-quality magnet list , " Constantinides said, "to be launched very long . "

Modern iron-based or ferrite magnets, on the cheap and abundant raw materials have a hook , which is also relatively strong enough magnetic and corrosion resistance are the champion , but they have one fatal flaw : the energy density is too low. This means that if you want a strong magnetic field , then you must use large enough to make a terrible giant pile of ferrite magnets .

" ferrite magnet is large and heavy big iron . "Lewis added.

For the heavy machinery industry, or for use in large-scale power units , this is also decent , but in today's electronic age crafted , we need a more exquisite stature magnet .

How can we create such a magnet to it? Large number of electrons in solid materials and spin interactions between them are too complicated, theoretical physicists want to accurately determine their behavior is simply no chance of winning , so manufacturers better magnet largely dependent on metallurgy family's dark magic : Mix all possible elements, and then placed in a magnetic field , to see how the wheel of fortune will change .

Shen Nong tasted a hundred herbs such methods have been tested. 1930s synthetic aluminum - cobalt - nickel- magnet , the energy density is twice the best ferrite magnets , but the real breakthrough was discovered more than 1970 rare earth elements in the lanthanide or called magnetic potential is beginning . These elements on the periodic table is always a separate area , without exception, can contribute to a large number of spins parallel to each other even woven into a piece of electronics . Samarium cobalt and rare earth elements with a mixture made ​​of magnets, storage or even than aluminum - cobalt - nickel- magnet even twice as high.

Of course , the biggest star in the draft but also is made ​​of rare earth neodymium iron and boron plus made ​​magnet. Prior to the 1990s , these neodymium magnets has been rapid development , so that the magnetic field of a magnet fingernail generated so much , even stronger than the Earth's iron core of the entire field thousands of times . Under "room temperature , neodymium magnets are the strongest magnets we currently know . " Constantinides so commented.

The problem lies in the " room temperature " is . Early Neodymium has a nasty flaw - thermal disturbance will destroy those carefully arranged always good spin , so the magnet demagnetization , and over 100 ℃, complete loss of magnetism , but just need a little building, a ready solution in sight patch : to get a more thermodynamically stable structure , just a fraction of neodymium atoms to a few percent , replacing it heavier companion - Dy .

Ultimately, this has brought a revolution in the magnetic field . The power transmission from the vehicle to allow the hard disk , CD and DVD disc rotates at high speed motor ; required from the speakers and the headphone will be converted into current pulses of acoustic diaphragm to medical magnetic resonance imaging (MRI) of the ultra-high the density of the magnetic field - whenever needed with a minimum volume of local produce maximum field will flash a neodymium magnetic figure.

As of 2010 , despite the nice affordable ferrite magnets in weight proportion still holds the bulk of sales , but sales of the total price point , neodymium-based magnets are more than 1-2 times faster than all other magnets.

With the blessing but a curse to . Magnetic Iowa State University researcher William McCallum (William McCallum) , explains: " When Neodymium was invented , people think it is a bit too good to head it. It REE demand , even more than the latter's reserves. "

REE does not actually rare , accounting for a total of a few parts per million of the Earth's surface , but they are difficult to explore . Over the past few decades , almost all of the world's supply of rare earths comes from China 's rare earth minerals, but China needs these elements to meet their economic and consumer demand , has recently started classes with high rare earth export tariffs - are the value of the global rare earth thirsty for knowledge when the mouth .

Such a horseshoe magnet , mostly ferrite magnets. They are characterized by abundant and cheap raw materials , the disadvantage is that there can not sufficiently compact and strong enough magnetic

The shortage of sources , not personal consumer electronics . "You can see each computer , which has about 50 grams magnet. " McCallum said. For millions of such devices , the amount of the required magnet is very substantial.

But compared to now swallowed magnets green energy technology , but trivial. Wind turbines, electric vehicles and electric bicycle motors must be strong and lightweight, only two neodymium magnet can have both . Each electric car motors require about 2 kg neodymium magnet , and an energy output of one million kilowatts of wind power generator takes about 2 / 3 tons . Only one wind generator will allow the magnet demand between 2010 and 2015 rose by 7 times.

By re-open the mine mountain pass in California , as well as the newly opened mines in Australia , the shortage of rare earths can be partially alleviated, but this is only a fraction of it. Electric cars , wind turbines or anywhere roaring , operating temperatures are high, which implies the need to neodymium and dysprosium in order to ensure the incorporation of a large magnetic stability. Dysprosium is precisely the lack of American and Australian rare earth mine , something only rich in Chinese mines .

Therefore, the industry demand for new super magnet has become increasingly urgent. In the United States , the Department of Energy has started as a pioneer advocate for the development of new magnet. Is shrinking called " counter " (React) "critical technologies of rare earth alternatives " (Rare Earth Alternatives in Critical Technologies) project, funded by 14 different groups , with a total investment of $ 22 million , the goal is to develop the required fewer REE magnets, totally not the best .

Lewis 's team is one of them , they are trying to use a mixture of iron and nickel to further squeeze the performance of high-end magnets. Usually, when you have two kinds of magnetic potential elements mixed together they actually will degenerate into some random lattice structure , so that the spin parallel to the more difficult to achieve , but there is an exception, is called Quartet taenite (tetrataenite ) mineral structure in which iron and nickel atoms form regular layered structure, with a strong magnetization orientation.

In the usual time scales , the solid structure of atoms fused into such unlikely neat natural conformation . In fact , not a geologic Quartet taenite product on the planet , now known natural samples are from a few dozen meteorites. "They're from a big , big, big asteroid separated , it took ten years before cooling into the hundreds of millions of the current structure , " Lewis explained.

We can not wait for billions of years. Lewis 's job is trying to make iron and nickel atoms fused rapid formation of this structure, by adding different impurities to guide them into the right order. "The fact is these two atoms to fool their brains , so they do not need to think through the test of time and can also form a solid marriage. "Lewis quips.

This is a bold vision . But with McCallum 's words: "' counter ' project is unique for each team are called curtain , two or three curtain curtain miracle plays. Lewis must find a way to eternal condensed into one minute or one hour , this is a miracle to reach her ​​. "

McCallum is a miracle of their own , so that cerium bring magnetic field. Although rare earth cerium is , but in the mountain pass more than rich mineral deposits in it , about half of the total weight of rare earth elements mine . " If successful , the whole economy will be altered rare earth industry . " McCallum look forward to the future.

But there is a problem that lie in front of each cerium atom has a change point forming a magnetic spin of a single electron , but the structure once it binds to other components , the cerium atoms will contribute electrons, so it is highly unstable magnetic , especially in some critical temperature range.

McCallum 's work mainly through the structure by adding some elements of atomic Impartial enough , let not send cerium atoms and courteous , but even feasible , it is impossible that shine like cerium , neodymium , and fortunately it not shoulder this responsibility. He explained: " look at the difference between the non- rare earth rare earth magnets and magnet , described as hanging in every day . " Thus, any non- magnet rare material, as long as a place in the neutral zone , the fever will let dysprosium , neodymium and then let cool .

Constantinides also has a similar goal . "We do not need to replace neodymium , " he thought so , " we need to do is to find some of the material , price, performance with complementary . " His company is carrying out two broad attempt. First, by using high-performance computing to eliminate aluminum - Nickel - Cobalt magnets rare earth elements such as existing non- short board. Another strategy he described as a wasteland , is to use complex algorithms auditions in the limited nature of magnetic material library, through the analysis to find the next superstar.

Constantinides said: " nickel, iron and cobalt is highly decorated , the question is can we find a more intelligent combination of these elements so that a more hard-edged . "However, he did not Chi Wang quick fix , " the number of floating point operations per second (Flops) it needs to remember the needs of trillions of times . "

Meanwhile, the U.S. State of Virginia Commonwealth University in Richmond Everett Carpenter (Everett Carpenter) and his team , is looking at a more unlikely candidate : Carbon . Graphite and diamond is not known magnetically , and made ​​of carbon was added to the iron- steel magnetic be weakened, but the fine carbonaceous nanoparticles bind with other elements , the result obtained is very different .

"We actually can enhance the magnetic properties of materials, " Carpenter said, " and it is greatly enhanced. "He believes that this kind may eventually tempered into a steel magnet , neodymium magnet beat , and the price is much cheaper. The most important question is how to make these tiny magnets grow into suitable size.

Right now , both Carpenter or any of the other team " fight back" programs , are not claiming to have made a breakthrough . So Lewis think she has a chance of winning it a few ? "Oh, we set ah, very small, " she laughs , but taking into account the effect of the magnet support the electrification of our modern lives , we should all pray for a miracle to happen, " even if it is found that a glimmer of hope , may earthshaking . " By 2015 , global demand for magnet industry might result in a shortage situation


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