Preparation of Cobalt Chromium Molybdenum Powder for Metal Injection Molding

In order to expand the application range of cobalt-based alloy in metal injection molding (MIM) process and meet the design requirements of MIM products, the preparation process of cobalt-chromium molybdenum powder was optimized. The water gas atomization process was put forward to prepare cobalt chromium molybdenum powder, the important parameters of metal melting process were defined, the relationship between atomization water pressure and the morphology, particle size distribution and oxygen content of cobalt chromium molybdenum powder was discussed, and the comparison with the conventional water atomization process was made. The results of process optimization show that different atomization water pressure has certain influence on the particle size distribution, morphology, vibration density and oxygen content of CoCr Mo powder during atomization. The median diameters D50 and D90 of the prepared CoCr Mo powders decreased significantly with the increase of atomizing water pressure, and the yield of powders less than 25μm increased significantly. When the atomizing water pressure is in the range of 90~110 MPa, the oxygen content of powder decreases with the increase of atomizing water pressure. When the atomizing water pressure is 90 MPa, the vibrational density of powder has reached more than 5.23 g·cm~(-3). When the atomizing water pressure increases, the vibrational density decreases slightly. The proportion of irregular powder particles is relatively reduced. The cobalt chromium molybdenum powder prepared by this process is nearly spherical and the powder is fine, which is better than the powder prepared by water atomization and finer than the powder prepared by gas atomization, and it meets the standard of injection molding process. The optimized preparation process of cobalt chromium molybdenum powder has a wide application prospect in the actual manufacturing industry and can provide more choices for the metal injection molding process.