RWMA Resistance welding Tungsten Copper Electrode, CuW or WCu is a mixture of copper and tungsten. As copper and tungsten are not mutually soluble, The material is composed of distinct particles of one metal dispersed in a matrix of the other one. The microstructure is therefore rather a metal matrix composite instead of a true alloy.
The material combines the properties of both of the Metals, resulting in a material that is Heat-Resistant, Ablation-resistant, Highly Thermally and electrically conductive and easy to machine.
Parts are made from the CuW composite by pressing the tungsten particles into the desired shape, sintering the compacted part, then infiltrating with molten copper. Sheets, rods, and bars of the composite mixture are available as well.
Commonly used copper tungsten mixtures contain 10–50 wt.% of copper and the remaining portion being mostly tungsten. The typical properties are dependent on its composition. The mixture with less wt.% of copper has higher density, higher hardness, and higher resistivity. The typical density of CuW90, with 10% of copper, is 16.75 g/cm3 and 11.85 g/cm3 for CuW50 . CuW90 has higher hardness and resistivity of 260 HB kgf/mm2 and 6.5 µΩ.cm than CuW50.
TYPICAL PROPERTIES OF COMMONLY USED COPPER TUNGSTEN COMPOSITION
|wt. %||g/cm3≥||HB Kgf/mm2≥||µΩ.cm≤||%≥||Mpa≥|
- Heat sinks as passive cooling elements of electronic devices
- Electrodes for resistance welding
- Electrodes in electric spark erosion cutting machines
- Arcing contacts and vacuum contacts in high and medium voltage breakers or vacuum interruptions
|TUNGSTEN WT. %||55||68||70||75||78||80||85||90|
|Tungsten wt. % 55 68 70 75 78 80 85 90 UTS (MPa)||434||517||586||620||648||662||517||483|
|Thermal Conductivity (W/(cm K))||2.4||2.1||2.01||1.89||1.84||1.82||1.75||1.47|
|Electro Resistance at 20°C||3.16||3.33||3.41||3.51||3.71||3.9||4.71||6.1|