RARE EARTHS CRITICAL TO AMERICAN DEFENSE

Industrial Mineral Article by Harold Hough

In these days of Defense Department cutbacks, the US military is spread thin. It still has worldwide obligations in addition to winding down a war in Afghanistan. Then there remains the potential of involvement in Syria.

Fortunately, the US military has one asset on its side – Rare Earth Elements (REE). These allow our small, professional military to multiply its potential by seeing more, flying through enemy airspace undetected and hitting targets more effectively. Rare Earth Elements have an important role in the defense industry.

They are used in lasers, radar, missile-guidance systems, satellites and aircraft electronics. And many military systems also rely upon commercial computer hard drives that use rare earth magnets.

Specific examples of rare earth-driven technologies include the navigation system for the M-1 Abrams battle tank, and the electric drive for the Navy's DDG-51 destroyers. The GAO report states, “Defense systems will likely continue to depend on rare earth materials, based on their life cycles and lack of effective substitutes.” Weapons created for the military by Lockheed Martin, Raytheon Co., General Dynamics Corp. and Huntington Ingalls Industries Inc. use 175 metric tons of neodymium iron-boron magnets every year.

Proof of REE’s importance in defense applications was made more apparent in September, when Russia announced it was investing $1 billion in weaning itself from reliance in Chinese REE production. “The (Russian) President (Vladimir Putin) and the government have set a task to expand rare earths production as Russia's stocks are almost depleted,” state industrial and defense conglomerate Rostec told Reuters in September.

One critical REE use is in jet aircraft engines. A coating of yttrium, which can withstand high levels of heat, is used inside jet exhaust systems and on the turbine blades.

REEs are also critical to make sure American bombs are on target. The Ground Laser Target Designator, which allows infantrymen to guide munitions onto targets and estimate ranges, depends on neodymium-doped yttrium-aluminum garnets.

One of America’s military strengths is stealth and REEs are critical in their application. Take stealth helicopters, which present special problems. Radar absorbing materials and radar cross section mean less, since helicopters fly close to the earth. Instead, masking the noise of a helicopter is the major problem.

Reducing helicopter noise isn’t a new science. Aerospace engineers know that redesigning rotor blades and tips, in addition to increasing the number of blades can significantly reduce the percussive thump we all recognize as the signature of a helicopter.

However, that isn’t enough, so stealth engineers have put a new technology into the stealth mix – white noise generators. Like the ones you can buy for your home, they mask and cancel out distracting noises. But what the Department of Defense uses for their stealth helicopters puts the home ones to shame.

Not only can these super-sized noise generators, hidden behind domes on the helicopter, help cancel out the blade noises of a helicopter, they can play a few other tricks on listeners. As anyone who has listened to a train move towards them and then away, the frequency of the noise can help a listener tell if an object is moving towards or away from them. This is known as the Doppler Shift.

Stealth helicopters use this principle to play games on your ears. They can change frequencies so it appears that a helicopter moving towards you sounds like it is moving away from you. Combined with low radar cross section and low infrared signature, these helicopters can truly confuse an enemy.

This is where rare earths come into play. There is only one magnet that is powerful enough and able to withstand the heat enough to carry this out – Samarium/Cobalt Magnets. They can withstand temperatures of 700 degrees Celsius without losing their magnetic properties. Neodymium magnets, which are more powerful, would fail in such heavy use.

The good news is that the US is the second largest producer of samarium and the US government has realized the importance of Rare Earths. The Mountain Pass Mine, once the largest REE mine in the world, has begun limited operations and is already one of the largest rare earths operations in the world. This alone will reduce our foreign reliance on REES by 40%.

Although the US allowed China to gain leadership in REE production decades ago, it appears that we have realized the error of our ways before it was too late. One can only hope that future enemies of America will meet their demise with American mined Rare Earth technology.