The incandescent lightbulb has been making homes safer and brighter for over 100 years. After centuries using fires, candles, oil lamps and gas, the invention of the incandescent lightbulb transformed daily life.
Tungsten was the eventual material of choice of this innovation, making a bright and long-lasting light.
Thomas Edison is usually credited with the invention of the lightbulb, but his bulb was actually the first commercially successful product rather than the original invention. Edison’s bulb used a carbonised bamboo filament which could burn for up to 1,200 hours.
It was in 1904 when a Hungarian company produced the first tungsten filament and then in 1906, General Electric managed to make a ductile tungsten version. Tungsten filament was very fragile and hindered its usage but William Coolidge at GE was able to make it ductile by swaging and sintering. Ductile tungsten allows the wire to be coiled up, increasing the bulb’s lifespan and making it shine brighter.
The final step to creating the bulb we have known up till recently, was the addition of inert gas into the glass case which increased the luminosity. Quickly GE’s lightbulb was the consumer preference, with market domination by 1914.
We have recently see the phasing out of tungsten filament bulbs, starting in 2009 in the EU. With the replacement of these bulbs by low energy versions, which are not quite the same as their tungsten predecessors. During the phase out, incandescent bulbs were stockpiled by those not keen on the new bulbs. Energy efficient bulbs are said by some to provide a ‘colder’ light as well as taking a while to warm up to their full brightness. Over time, people will probably get used to the new bulbs as those last century gave up their oil lamps and candles.
Working hard
Tungsten and carbon alloyed is Tungsten Carbide (WC), and is one of the hardest alloys used. With a hardness on the Mohs scale of between 8.5 & 9 (diamond is 10 on this scale) combined with its high melting point makes it a good choice for drill bits and tools used to machine steel and stainless steel. Another major application is for armour piercing ammunition, which first started during WWII.
