Powder metallurgy method making thermoelectric materials bismuth telluride (Bi2Te3) alloy, working temperature is
close to 450 ℃ can be used in the manufacture of household refrigerator, air conditioner, small detectors and sensors, etc.
Bismuth telluride with a small amount of antimony telluride (Sb2Te3) alloying can form P type semiconductor solid
solution, and with a small amount of bismuth selenide (Bi2Se3) alloying can form N type semiconductor solid solution.
Bismuth telluride, it and other components to forming alloy have highly anisotropic structure. the most commonly used
method making bismuth telluride alloy is single crystal directional crystallization. But this method is low productivity,
segregation, and poor mechanical properties.
Canada after three years development, has developed a method of of producing bismuth telluride alloy by powder
metallurgy. It is mechanical alloying 2-5 mm diameter granular pure elements (such as Bi, TeSeSb) powder in a ball mill,
after about 3h can be obtained for 5~10 m particle size alloy powders. Powder is cold pressed under the pressure of 360
mpa , compact body relative density of 80%, And hot extrusion in inert atmosphere into the 963.5 mm bar, extrusion
temperature 420-49
