How to Make Copper/Tungsten Disulfide/Graphite Composite Electric Brush?

Copper/tungsten disulfide/graphite composite electric brush can be prepared by hot-pressing sintering of electrolytic copper powder, tungsten disulfide powder and graphite powder. It is an ideal brush material with good conductivity and excellent friction performance.

Electric brush is an important component of motor, which is responsible for conducting current between rotating parts and stationary parts. Its performance is affected by both mechanical and electrical loads. The high temperature produced on the contact surface will reduce the brush performance by the effect of friction heat and Joule heat, which causes severe wear.

Copper/tungsten disulfide/graphite composite electric brush can be prepared by the hot pressing of powder metallurgy. It involves the following steps:

Step One: Reagents preparation. Electrolytic copper powder (purity is 99.5%, particle size is 45 microns), tungsten disulfide powder (purity is 99.9%, particle size is 45 μm) and graphite powder (purity is 98.5%, particle size is 45 μm) are taken.

Step Two: Copper powder, tungsten disulfide powder and graphite powder are ground in planetary ball mill for 2 hours under the protection of high purity argon. The volume fraction of copper powder is 40%,which is the same as that of graphite powder. And the volume fraction of tungsten disulfide powder is 20%.

Step Three: The mixed powder is placed in graphite mould first and then it is put in ZT-40-20Y vacuum furnace. Copper/tungsten disulfide/graphite composite can be prepared by the hot-pressing sintering of the mixed powder. The process parameters of hot pressing sintering are as follows: pressure 30 MPa, temperature 800°C, holding time 1 h, heating rate 10 °C/min. The preparation is carried out under the protection of high purity argon.

Step Four: The sintered composite of copper, tungsten disulfide and graphite is made into an electric brush with a size of 24 mm x 20 mm x 8 mm.

The prepared electric brush with good conductivity and friction performance is used in motor to reduce the friction loss. And the preparation process is simple, clean and time-saving.

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