The influence of La element on tungsten powder morphology

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Tungsten powder is a kind of metal tungsten that appears to be grey silver powder and is the principle raw material in producing powder metallurgy tungsten products and tungsten alloy. By mixing tungsten powder and other metal powders, it can be made into various tungsten alloys, such as tungsten-molybdenum alloy, tungsten-rhenium alloy, tungsten copper alloy, high-density tungsten alloy and so on. The other important application of tungsten powder is being made into tungsten carbide powder which can be further manufactured into the carbide tools, such as turning tools, milling cutters, drills and moulds, etc. Besides, the metal tungsten powder added with La element will have better performance and can obviously improve the anti-seismic property of tungsten powder.

After observing the tungsten powder that has different La content with SEM, we find that the morphology of tungsten powder will have obvious difference with different content of La. Usually the normal morphology of tungsten powder grain appears to be torispherical and has uneven size distribution, while the morphology of tungsten powder containing low La content is in spherical shape and polyhedron, besides, it will adhere to each other between grains and grains and aggregate into rolls; the morphology of tungsten powder that has high La content is in regular polyhedron. Obviously, by adding La element, the energy state of tungsten powder crystal will be changed, thus the powder will appear to be regular polyhedron.