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Tungsten

Tungsten gets its periodic symbol from its German name, Wolfram. Tungsten is a "refractory" metal, meaning that you have to heat the hell out of it before it melts. This is what allows it to be used as incandescent lightbulb filaments (remember those?) This property also allows tungsten to be used in high-temperature cofired ceramics, because the ceramics melt below the temperature that tunsten vaporizies or catches on fire. Due to its relatively high resistivity, co-fired ceramic feed through plugs employing tungsten have appreciable RF loss. If they used gold conductors, they would have even higher loss because the gold would have burned away during firing.

All values except melting point are assumed to be at 25 degrees C, and may vary dramatically over temperature.

Formula or Composition: W
Bulk Resistivity: 5.6 μΩ-cm
Bulk Resistivity: 5.8 E-8 Ω-cm
Bulk Conductivity: 1.79E7 S/m
Temperature Coefficient of Resistivity (TCR): ppm/°C
Mass Density: 19.3 gr/cc
Heat Capacity: 135.9 J/kg/°C
Thermal Conductivity (k): 169 W/m°C
Temperature Coefficient of Expansion (TCE): 4.5 ppm/°C
Melting Point, °C: 3410 °C
Melting Point, °F: 6170 °F

 

 

Author : Unknown Editor

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