A Glance Back at Tungsten ca. 2007, Courtesy of ITIA
The International Tungsten Industry Association (ITIA) is an esteemed organization of which our colleagues at Nippon Tungsten have been a member for many years. Where Metal Cutting Corporation is an expert in how to cut tungsten and in using it to create precision parts from wrought rod and fine wire, the ITIA is more focused on the powder and tonnage side of the business. However, the highly respected ITIA is of interest to anyone in the tungsten business, where unique properties including the high melting point of tungsten (at 6192°F, or 3422°C), its low vapor pressure (temperatures > 3000°F, or > 1650°C), and its high tensile strength have made tungsten useful in a wide range of applications.
In fact, we recently came across a marvelous look back at tungsten in an old ITIA newsletter article called “A Family’s Day with Tungsten.” Almost a decade after the piece was written, just for fun we decided to do an update of sorts — looking at how many tungsten uses circa 2007, as experienced by a theoretical family of four people (a father, a mother, and two children), have stood the test of time.
At Home in the Morning
That day in 2007 began with the dad waking up very early (and quietly, so as to not disturb his wife and kids) to the gentle vibration of his mobile phone under his pillow. While the type of phone pictured in the article is long gone — replaced by the slimmest of smart phones — the mechanism of a tiny tungsten part rotated by an electric micro-motor inside the phone to create the vibration is one of the tungsten uses that is still utilized today.
As the dad tiptoed around the house, he noted various lighting, including the soft glow of the bedside lamp using a 15W incandescent bulb with a tungsten filament and the bathroom’s bright halogen spotlights with high-performance tungsten wires. The reality today is that incandescent bulbs with filament wire are waning, and even CFLs are fast ceding to the efficiency of LED lighting. (As much as wire filament is one of those tungsten uses that is good for our business, we are not among the LED deniers!)
Tungsten Uses on the Road and in the Air
Finally in his car and on the way to the airport, the dad switched on his window de-icer, which used tungsten filament wires embedded in the front and rear windshields. This application never really caught on in automobiles made in the United States, but it is still used widely in Europe. (Moreover, Metal Cutting today provides tungsten filament wire for this purpose in aerospace windshields.) The dad noted that his 10-cylinder car engine ran surprisingly smoothly for a diesel; this was due almost 22 pounds (10 kg) of tungsten parts placed around the crankshaft to reduce vibration. That thinking has gone the way of 10-cylinder diesels in general, in favor of the evolution of lighter and more energy-efficient automobiles.
Narrowly avoiding a collision on the highway, dad quickly leaned on his car horn — an application that, then AND now, requires the flow of electric current and depends on switches made of pure tungsten, which in turn depend on expertise in how to cut tungsten. In the pre-dawn, a thin layer of tungsten bronze on his rearview mirror reduced the glare of the headlights behind him; this, too, is one of the tungsten uses that is utilized today. As it began to snow, the dad thought of his brother-in-law who lived in Finland, where tires studded with cemented tungsten carbide were — and still are — useful in icy winter weather, where local government allows them; the studs’ hardness and abrasion resistance help to prevent cars from skidding. Of course, today’s automobiles include an ever-growing range of active safety technology designed to improve both safety and performance.
As he neared the airport, the dad saw cargo trucks with labels saying they were equipped with modern emission reduction equipment. DeNOx catalysts, used then and now on many truck diesel engines, reduce nitrogen oxide concentration in exhaust and are made from a tungsten containing ceramic — two materials that work well together, given the ultra-high melting point of tungsten. In addition, today the diesel injectors for these trucks are made using Metal Cutting’s own tungsten electrodes.
Boarding an airplane and finding his seat near one of the wings, the dad noticed the engine turbines, in which the turbine blades in the engine’s high-temperature zone were and are still made of tungsten containing super-alloys — another application that benefits from the high melting point of tungsten. During takeoff, he looked out the window and noticed the wing flaps and aileron at work; in 2007 and today, tungsten heavy metal counterweights are part of the mechanism that controls the force exerted on the flaps. Ironically, while today we now pay for all luggage and must pay extra for overweight bags, airplanes themselves are filled with heavy counterweights. However, these are precision engineered for specific locations and safety purposes, so we’re not complaining.
Dad brought out his laptop and iPod to pass the time and prepare for his business meeting. While such electronic devices have evolved extraordinarily in the past decade, tungsten uses are still integral to their manufacture — from the printed circuit boards inside, still machined using cemented carbide routers and micro-drills, to the integrated circuit chips that use tungsten conducting wires or plugs and tungsten silicide gate material. In addition, tungsten and molybdenum alloys are still used in the production of device displays.
Tungsten in Medical and Dental Applications
For the mother of the family, the story detailed some important appointments that featured tungsten uses in medical devices. She made a trip to a hospital for a computer tomography (CT) scan of her spine, to try to determine the cause of some long-time back pain. Although magnetic resonance imaging (MRI) is probably more widely used today, then and now a CT device could be used to generate 3D images using a series of X-ray tubes, each of which has an electron gun with an electrode made of tungsten, as well as a rotating anode made of tungsten or a tungsten rhenium alloy. Additionally, tungsten is still used in the shielding of the entire CT machine.
After a good report from the CT scan, showing no serious problem, the mom headed to a date at the dentist’s office. There, a panorama x-ray of all her teeth was taken — and once again, tungsten anodes played a part in the x-ray machine. Calcium tungstate was used as fluorescent material in the x-ray film. Additionally, the heavy protective apron that the mom wore was made of tungsten powder dispersed in latex, which shielded her against radiation and was more eco-friendly than lead.
Today, digital imaging is more prevalent than the use of traditional x-ray film at the dentist’s office, but basic x-ray technology remains the same. Interestingly, here in the United States our dentists still use protective aprons made with lead. But, wouldn’t it be great if they switched to the more environmentally friendly tungsten?
Returning to 2007 — bad news for mom: She needed a root canal! Most of the drills used by the dentist for cleaning and shaping were made of fine-grained, extremely sharp edged cemented carbide. True then and still true now, this drill material produces less friction, which means less heat and less pain for the patient — finally, some good news for mom.
Come Back Next Time to See How a “Day with Tungsten” Ends
We’ll continue the family’s story in our next blog. In the meantime, for an enjoyable blast from the not-so-distant past, we invite you to read the ITIA article for yourself and consider how much you think tungsten uses have changed — and how much they haven’t — over the past decade.