Many of the legacy applications for tungsten wire remain strong and necessary.
There are a variety of products in general industry, ranging from filaments to furnaces, in which tungsten wire is used and remains without substitute. Given tungsten’s unique elemental properties, it is highly unlikely there will ever be a superior alternative for certain industrial applications in which tungsten wire is a key component. There are even lamp products in which the poster child for technological obsolescence, the incandescent lamp, cannot be replaced with newer technologies.
Tungsten wire shines where blinking is required.
Despite the first wave of CFLs and the seemingly unstoppable conversion to LEDs (or at least it will be unstoppable once the price falls even further), there are certain lamps that CFLS and LEDs simply cannot replace.
For example, in a wonderful instance of irony, we all know that electronic devices don’t like to be turned on and off rapidly and repeatedly — yet, there are certain lamps whose sole purpose is to do precisely that, such as the turn signal or flasher function in an automobile. Here, the blinking of the lamp, requiring the on-off thermal cycling of the electronic component, is not at all suitable for LEDs. In the early days of enthusiastic LED adoption, there were various schemes to develop a mechanical shutter that would allow LEDS to remain on constantly while appearing to blink. However, it quickly became clear that this was a cumbersome and unworkable solution for products with heavy use as safety equipment, requiring long life, high temperature and exposure resistance, and endless repeatability.
So, the next time you signal a turn in your car, consider that you may very well owe that capability to the presence of a tungsten wire bulb, which remains the long life, low cost source for that blinking solution.
Tungsten properties provide advantages where temperatures are high.
With no other elemental metal having the same heat resistance and shape retention properties, tungsten wire also remains necessary outside of the lighting industry.
For instance, in the case of industrial furnaces, tungsten wire holds its shape at the highest temperatures, making it excellent for support structures, oven mats, and other weight-bearing surfaces that need to maintain the position of the object being subjected to the furnace temperatures. Tungsten wire’s heat resistance enables it to hold the object in the proper location in the hot zone without sagging, collapsing, falling apart, or otherwise moving the object out of the optimal position.
Even though integrated circuits are replacing many electronic applications that use tungsten or tungsten wire, you cannot make an integrated circuit without tungsten wire. Why is this? Most integrated circuits made today start with a single crystal ingot of silicon, called a boule. It is created by dipping a small seed crystal into pure molten silicon in an oven and slowly pulling the boule (like pulling taffy) so that it forms a larger, cylindrical crystal. Once solidified, the crystal is sliced into wafers and polished to provide very regular, flat substrates for semiconductors. And the only material that is suitable for pulling a boule, and uniquely capable of performing as designed in the very high temperature of the silicon manufacturing process, is a cable made of woven tungsten wire.
Another industrial application in which tungsten wire’s high temperature properties prove to be indispensible is in the borescopes used to take measurements of the interior space of very high temperature environments. For areas that are inaccessible by other means, these borescopes are commonly used in the inspection of engines, turbines, pipes, and tanks.
Yet another benefit of tungsten at high temperatures is its extremely low vapor pressure, which comes into play in applications such as electron emitters, ion implantation, and vacuum metalizing coils. For instance, vacuum metalizing coils are used in the process of coating the surfaces of low-cost plastic products — such as toys, jewelry, cosmetic containers, and small decorative parts — with metal evaporates. The products (or parts) are placed in a vacuum along with the coating metal, which is heated with the metalizing coils until it has evaporated; the resulting vapor settles on the products/parts, quickly and completely coating their surfaces with a thin, uniform film of the metallic evaporate.
Where the Heat Is On, Tungsten Wire Still Excels
The possibilities are endless. These are but a few examples of the many intriguing industrial uses for tungsten wire — a product that keeps proving its value in applications where its unique properties deliver results that are difficult (perhaps even impossible) to achieve through other methods at a comparable cost.