Annealing Process Effect on Tungsten Copper Electrode Properties

Annealing process controlling is crucial in the process, its time and temperature has an effect on the properties of tungsten copper electrode directly. After infiltration cooling rate has a great impact on the copper layer quality, too fast cooling will be easy to produce pores and tiny cracks. Meanwhile, due to the furnace temperature unevenness, the copper layer thickness of products are not easy to be uniform, so it requires the use of a copper infiltrated after annealing treatment, which further improving the performance of a tungsten-copper electrode. Some experiments shows that annealing process has a great influence on the electrical conductivity of tungsten copper electrode, there is a table of the electrical conductivity of W-25Cu tungsten copper electrode at different temperature.

Some experiments shows that annealing process has a great influence on the electrical conductivity of tungsten copper electrode, there is a table of the electrical conductivity of W-25Cu tungsten copper electrode at different temperature in the part one. The table shows that when the annealing temperature reaches 800 ℃, the electrical conductivity of tungsten copper electrode is the highest, after which the temperature continues to rise, the conductivity decreased. Theoretically, this is due to the elimination of internal stress and the Cu phase recrystallization. On the one hand, when tungsten skeleton is starting cooling process after infiltrated at high temperature, it produce large internal stress because of the a great difference between the coefficient of thermal expansion of tungsten (W) and copper (Cu), which affects the electrical conductivity of tungsten copper electrodes. On the other hand, copper phase recrystallized at 400 ℃, and when the temperature rises to 800 ℃, copper atom lattice distortion reduced, the crystal defects supplemented and improved conduction mechanism of Cu is further reflected. However, with further increase of annealing temperature, changes in Cu phase grain boundaries will gradually slow, the impact on the conductivity becomes negligible.