Concept of metal tungsten -

Tungsten, a Swedish chemist at the club, in 178 l found when using acid decomposing tungsten acid, but after sixty-seven, people made of pure metal Kekai tungsten & Molybdenum copper molybdenum. Pure tungsten is silvery white metal, only powder or filamentous pot is a gray or black. Electric light bulb will used long black, it is because of the light bulb inside have a layer of tungsten powder. Tungsten is very heavy, 1 cubic meters of copper tungsten weighing 19.1 tons, and almost like gold, so its Swedish original intention, is the meaning of "heavy". Tungsten and very hard, people is to use the hard stone, diamond wire drawing die, the l mm diameter molybdenium diamond hole through more than 20 small down gradually, to put it into a filament one percent only a few millimeters in diameter. A kilo of tungsten ingots can grow up to four hundred kilometers of the filaments. Now, incandescent lamp, tube and even our country in recent years made of novel "iodine tungsten lamp". Are made of tungsten filament. According to statistics, every year all over the world now than incandescent lamp and tube production for billions of!