Rod-like W Grain in W-Cu Electrode Formation—Powder Morphology(2/2)

By many trials and experimental data analysis and SEM photographs, the researchers summed up the possible causes of the four rod-shaped tungsten grain, and for its analysis and discussion. They are the influence of powder morphology, the rearrangement and combination of tungsten (W) grains in the process of microwave infiltration, the growth of grains caused by elution after infiltration and the growth of grains. This part we are concentrated on the influence of powder morphology. Theoretically, morphology of the powder particles directly affect flow ability of the powder and the suppression of performance, but also have a certain impact on the microstructure of the sintered body strength.

Viewed from the structure, tungsten powder is a typical cubic crystal structure, and thus the rod-shaped tungsten grain microwave infiltration is unlikely to be due after the tungsten powder material morphology caused. Then analyze the morphology of tungsten skeleton compact SEM picture, which has a large amount of bores, but there is no rod-like w grains. In addition, for the same group of powder, which was prepared under the same conditions (temperature, pressure, etc.), conventional copper infiltrated tungsten alloy electrode samples showed distinct grain growth mode, there is no obvious grain tungsten rod appears, which further proved a rod-shaped tungsten grains and powder morphology no direct link, but there is a certain connection with the microwave sintering in the microwave field.

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