is excellent high temperature thermocouple materials

Tungsten doped tungsten powder is added in about 1% of silicon, oxides of aluminum and potassium in the vertical melt (from resistance sintering) process, volatile additives hydroxide, the formation of pores in the material, the trailing edge of the processed hole axially elongated; annealed to form elongated hole parallel to the filament axis dispersed bubbles line, this dispersion foam bubbles known as potassium. Potassium tungsten wire bulbs impede lateral grain growth, improve anti-sagging properties of high-temperature tungsten, but also to improve the room temperature ductility after recrystallization, help around the wire and transport storage. China tungsten-doped high-temperature creep values ​​by WAl1, WAl2, WAl3 three kinds of grades. In the W-ThO2 alloy, since the added amount of thermal stability, good dispersion of the particles ThO2, not only can reduce the electron work function, can inhibit the grain growth of tungsten, the material has a high recrystallization temperature, excellent high-temperature strength and creep resistance. Tungsten-thorium alloy is widely used in not only the thermal electron emission material, and is an excellent electrode material.Tungsten-rhenium alloys, rhenium addition, not only can improve the strength of the material, to improve the recrystallization temperature of about 200 ~ 400 ℃, the secondary recrystallization good plasticity, grain growth is slow, and can significantly reduce plastic - brittle transition temperature. Added if more than 30% of rhenium, it will damage the alloy processing performance. Tungsten-rhenium alloy also has a high thermoelectric power, at 2200 ℃, its thermoelectric power linear relationship with temperature. Tungsten-rhenium thermocouples measure the temperature up to 3000 ℃, is excellent high temperature thermocouple materials