The invention relates to a method for preparing fine spherical niobium powder, belonging to the field of powder preparation. The use of plasma as heat source has great technical advantages in the spheroidization of micron submicron and some nanomaterials. Rf plasma torch has large arc, stable arc flow and easy to adjust and control, which makes it easy to be applied in the field of ultrafine powder material processing technology. At present, the technology of using plasma to treat powder has a certain technical level in foreign countries. Canada's TEKNA (TEKNA) company developed plasma powder treatment system in the induction plasma technology in the international leading position, has achieved Tungsten, Molybdenum, Rhenium, Tantalum, Nickel, Copper and other metal powder and SiO2, ZrO2, YSZ, Al2O3 oxide ceramic powder nodulization treatment. The domestic nuclear industry Southwest Institute of Physics uses self-built plasma spheroidization system to achieve the spheroidization of W, Al2O3 powder, high spheroidization rate, size up to 0.5 ~ 45μm, powder for thermal spraying and powder metallurgy, with good performance.
Because of the excellent application of spheroidized powders in some fields, the spheroidization of various powders, especially high-refractory powders, has become the demand for powder preparation. Niobium is a highly refractory metal, melting point up to 2740℃, can absorb gas, used as a degassing agent, is also a good superconductor, used in many high-tech fields. For example, in the field of high-energy physics, it is necessary to obtain high-performance, large-size niobium products, if the use of laser 3D printing process to prepare niobium products, compared with traditional processes, it is possible to obtain better performance and larger size products. However, in the use of laser 3D printing dense high-performance niobium products, the use of powder with irregular particle shape, in the printing of materials, poor fluidity, resulting in slow printing rate, and small packing density, easy to form holes, not dense; If spherical powder is used as raw material niobium powder, good fluidity, high packing density, uniform shrinkage of products after laser sintering can achieve more accurate dimensional control, uniform product density, low porosity, more dense, the preparation process time is greatly reduced, laser sintering power will also be reduced; Moreover, the impurity content can be further reduced by the radio-frequency plasma spheroidization powder, especially the trace oxygen impurity content, so as to further optimize the superconducting electrical properties of niobium products.
Under this background requirement, it is necessary to have a feasible method with certain production capacity to prepare fine spherical niobium powder.
