As an electrode material, tungsten copper alloy is required to have good compactness, wear resistance, corrosion resistance, and good electrical conductivity. This paper discusses the technological route of preparing high-performance tungsten copper electrodes from fine-grained tungsten powder, including four parts: studying the particle size of the powder, the preparation of high-performance tungsten skeleton, reasonable infiltration process, and the effect of adding metal elements on the performance.
First, the effects of three tungsten powders with different particle sizes (2.65μm, 4.32μm, 8.26μm) on the properties of tungsten copper alloys are described. Experiments have shown that the finer the particle size of the powder, the higher its density and hardness, but the poorer the electrical conductivity, the more heterogeneous the structure. Among them, for W-30Cu (that is, W70 tungsten copper) alloy, the density and hardness are highest with tungsten 2.65μm particles, which are 14.7g / cm3 and HB222, respectively, but the electrical conductivity is lower at 22.6% IACS.
Secondly, the tungsten skeleton preparation of tungsten powder with a particle diameter of 2.65 μm was studied. The effects of pressure and sintering temperature on the skeleton performance were investigated, and the optimal process conditions for preparing tungsten skeleton were obtained. Tungsten framework was pressed under 410MPA pressure, and sintered at 1300 ℃ under hydrogen atmosphere.
Then, the infiltration process of tungsten skeleton prepared from tungsten powder with a particle size of 2.65 μm was studied. The effects of different process factors such as temperature, time, atmosphere and post-treatment on the properties of tungsten copper alloy were investigated. Through experiments, the optimal process conditions for infiltration were obtained by infiltration of tungsten skeleton at 1350 ℃ under hydrogen atmosphere, and the infiltration time was 80MIN. The infiltrated samples were annealed at 800 ° C.
The addition of activating elements is usually beneficial to the sintering and performance improvement of the alloy. Based on this, this paper discusses the effects of adding a small amount of CO powder and Ni powder on the preparation and properties of tungsten copper alloy. The results show that the addition of trace amounts can significantly increase the density and hardness of tungsten copper alloys, but greatly reduce the conductivity of the alloys. Therefore, the addition of Co and Ni is not conducive to the preparation of high performance tungsten copper electrodes.
Through the above studies and repeated experiments, the optimal process system for preparing high-performance tungsten copper alloy (W-25Cu) was finally determined:
Tungsten powder with a particle size of 2.65 μm and a small amount of induced copper machining powder were sintered at 1300 ℃ to prepare a high-performance tungsten skeleton. Then, under the hydrogen atmosphere, the tungsten skeleton is infiltrated, the infiltration temperature is 1350 ° C, and the infiltration time is, and the annealing treatment is performed at 800 ° C after the infiltration, and the tungsten-copper composite material with better performance can be obtained.
At this time, the density of W-25Cu alloy is 14.78g / cm3, the hardness is HB240, and the electrical conductivity is 41.6% IACS. Its performance index exceeds that of similar domestic products, and is close to the level of imported tungsten copper electrode products, and the use effect is good.
First, the effects of three tungsten powders with different particle sizes (2.65μm, 4.32μm, 8.26μm) on the properties of tungsten copper alloys are described. Experiments have shown that the finer the particle size of the powder, the higher its density and hardness, but the poorer the electrical conductivity, the more heterogeneous the structure. Among them, for W-30Cu (that is, W70 tungsten copper) alloy, the density and hardness are highest with tungsten 2.65μm particles, which are 14.7g / cm3 and HB222, respectively, but the electrical conductivity is lower at 22.6% IACS.
Secondly, the tungsten skeleton preparation of tungsten powder with a particle diameter of 2.65 μm was studied. The effects of pressure and sintering temperature on the skeleton performance were investigated, and the optimal process conditions for preparing tungsten skeleton were obtained. Tungsten framework was pressed under 410MPA pressure, and sintered at 1300 ℃ under hydrogen atmosphere.
Then, the infiltration process of tungsten skeleton prepared from tungsten powder with a particle size of 2.65 μm was studied. The effects of different process factors such as temperature, time, atmosphere and post-treatment on the properties of tungsten copper alloy were investigated. Through experiments, the optimal process conditions for infiltration were obtained by infiltration of tungsten skeleton at 1350 ℃ under hydrogen atmosphere, and the infiltration time was 80MIN. The infiltrated samples were annealed at 800 ° C.
The addition of activating elements is usually beneficial to the sintering and performance improvement of the alloy. Based on this, this paper discusses the effects of adding a small amount of CO powder and Ni powder on the preparation and properties of tungsten copper alloy. The results show that the addition of trace amounts can significantly increase the density and hardness of tungsten copper alloys, but greatly reduce the conductivity of the alloys. Therefore, the addition of Co and Ni is not conducive to the preparation of high performance tungsten copper electrodes.
Through the above studies and repeated experiments, the optimal process system for preparing high-performance tungsten copper alloy (W-25Cu) was finally determined:
Tungsten powder with a particle size of 2.65 μm and a small amount of induced copper machining powder were sintered at 1300 ℃ to prepare a high-performance tungsten skeleton. Then, under the hydrogen atmosphere, the tungsten skeleton is infiltrated, the infiltration temperature is 1350 ° C, and the infiltration time is, and the annealing treatment is performed at 800 ° C after the infiltration, and the tungsten-copper composite material with better performance can be obtained.
At this time, the density of W-25Cu alloy is 14.78g / cm3, the hardness is HB240, and the electrical conductivity is 41.6% IACS. Its performance index exceeds that of similar domestic products, and is close to the level of imported tungsten copper electrode products, and the use effect is good.