Tungsten Vanadium Copper Composite Materials by Ball Milling

Among the many vanadium oxides, vanadium dioxide is different because of its rapid and sudden phase transition. Its phase transition temperature is 68 ℃, which can change reversibly from low temperature monoclinic system to high temperature tetragonal system, making its physical properties such as resistivity, optical transmittance and magnetic conductivity change greatly. This characteristic makes it have a great prospect in intelligent switch, electronic device and photoelectric equipment. The results show that tungsten can effectively reduce the phase transition temperature of vanadium dioxide, and copper can improve the conductivity of vanadium dioxide.

Using high energy ball milling method, the better the quality of the finished powder can be obtained, which will have a significant impact on the electrical and magnetic properties of the composite, that is, the phase transformation effect of the composite has been improved, and the doping method is roughly as follows:

Weigh tungsten-vanadium-copper composite powder, in which the volume ratio of V to Cu is 20-50:50-80; then mix the powder into the ball grinding tank, add the powder 15-60 times of the total quality of V_0.97W_0.03O₂ powder and Cu powder into the ball grinding tank, and mix the powder mechanically for 12-72h to obtain the composite powder; then ball mill the composite powder and the ball in the high-energy ball mill for 72h, and the rotation speed of the ball mill is 100-800r/min. After sieving, the powder was pre pressed by cold pressing die, the pressing pressure was 300KN, and the pressure was kept for 3-8 minutes to form composite blank;

Finally, the blank of the composite material is installed in a pressurized crucible and put into a vacuum high-temperature sintering furnace to vacuumize the furnace. When the vacuum degree reaches 10-1-10-3pa, the furnace is heated to 600-700 ℃ for 60-120min, and then cooled naturally. When the temperature of the vacuum sintering furnace is reduced to room temperature, the air pressure in the furnace is restored to 1 × 105Pa, then the composite blank is taken out, and the surface of the blank is heated. After machining, Cu V_0.97W_0.03O₂ composite was obtained.

By using high energy ball milling method, the preparation process of vanadium dioxide tungsten copper composite can be simple, the process can be controlled, the cost can be controlled, and the sudden change effect of electrical properties and magnetic properties of functional composite can be improved at different temperatures.

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