我的博客列表

2013年6月18日星期二

Tungsten Copper Heat Sink Resistance Welding

The high physical and mechanical properties, as well as the thermal and electrical conductivity, of refractory metal composites make these materials very suitable for die inserts and electrode facings, flash and butt welding dies, and hot upsetting. They can also solve heat balance problems
JBNR developed CuW75 to be used extensively in thermal mounting plates, chip carriers, flanges, and frames for high-power electronic devices. As a copper tungsten material, it’s a composite, so both the thermal advantages of copper and the very low expansion characteristics of tungsten can be utilized.
The combination of these two materials results in thermal expansion characteristics similar to those of silicone carbide, aluminum oxide, and beryllium oxide, used as chips and substrates. Because of its thermal conductivity and expansion characteristics, it works well in densely packed circuits.

Tungsten Copper

Tungsten Copper alloy is the composite of Tungsten and Copper, which own the excellent performances of Tungsten and Copper, such as heat-resistant, ablate-resistant, high-intensity, excellent thermal and electrical conductivity. It is easy to be machined. It is used widely in such industries as engine, electrical power, electron, metallurgy, spaceflight and aviation. Using CIP formation, sintered tungsten skeleton and infiltrating copper (silver) technology, large size and special shape products of tungsten-copper (silver) composites with 6-90 percent of copper are produced, such as electric contacts, electrode, refractory parts, heat sinks and parts of rocket, We can also produce sheet material, tubing, plate and other small products by mould pressing, extrusion pressing and MIM.

2013年6月4日星期二

Copper Tungsten Alloys--Refractory Metal Composites

Copper Tungsten Alloys--Refractory Metal Composites
Eagle refractory metal composite materials are a combination of tungsten or tungsten carbide combined with copper or silver. The manufacturing process is to press the refractory (tungsten or tungsten carbide), sinter the pressed compact at a high temperature, and infiltrate with copper or silver. All this is done under very closely controlled conditions. The result is a relatively hard materials with superior arc and wear resistance, high physical properties at elevated temperatures, and good electrical and thermal conductivity.

Tungsten Copper Alloy

Midwest Tungsten Service tungsten copper alloys are the perfect choice where high density, high thermal conductivity, or low thermal expansion are important. Electrical contacts, heat sinks, and resistance welding electrodes are all applications where MTS tungsten copper alloys can do the job. Check the options and properties below to determine which of our alloys is best suited to your needs. Most sizes and shapes can be supplied with short lead times. We can also manufacture parts from these materials to your speci

Advantages:
• High arc resistance combined with good electrical conductivity
• High thermal conductivity
• Low thermal expansion
Applications:
• Arc contacts and vacuum contacts in high/medium voltage breakers or vacuum interruptors
• Electrodes in electric spark erosion (EDM) cutting machines
• Heat sinks for passive cooling of electronic devices
• Electrodes for resistance welding

Thermal conductivity of tungsten copper composites

Thermal conductivity of tungsten copper composites
As the speed and degree of integration of semiconductor devices increases, more heat is generated, and the performance and lifetime of semiconductor devices depend on the dissipation of the generated heat. Tungsten–copper alloys have high electrical and thermal conductivities, low contact resistances, and low coefficients of thermal expansion, thus allowing them to be used as a shielding material for microwave packages, and heat sinks for high power integrated circuits (ICs). In this study, the thermal conductivity and thermal expansion of several types of tungsten–copper (W–Cu) composites are investigated, using compositions of 5–30 wt.% copper balanced with tungsten. The tungsten–copper powders were produced using the spray conversion method, and the W–Cu alloys were fabricated via the metal injection molding. The tungsten–copper composite particles were nanosized, and the thermal conductivity of the W–Cu alloys gradually decreases with temperature increases. The thermal conductivity of the W–30 wt.% Cu composite was 238 W/(m K) at room temperature.
We present the temperature dependence of the thermophysical properties for tungsten–copper composite from room temperature to 400 °C. The powders of tungsten–copper were produced by the spray conversion method and the W–Cu alloys were fabricated by the metal injection molding. Thermal conductivity and thermal expansion of tungsten–copper composite was controllable by volume fraction copper.