Effects of Copper Powder Morphology and Sintering Temperature on the Microstructure and Properties of MIM-fabricated Porous Copper

In this study, porous copper material was prepared from copper powders with different morphologies (near-spherical, irregular, and cluster-like) by combining metal injection molding and powder sintering technologies. The effects of power morphology and sintering temperature on the pore features, water absorption and mechanical properties of the sintered samples were studied. The results showed that at the same sintering temperature, the samples prepared from cluster-like copper powder exhibited the highest porosity, while those prepared from near-spherical powder had the lowest porosity. Correspondingly, samples prepared from near-spherical powder displayed the minimum volume shrinkage rate at all sintering temperatures. As the sintering temperature increased from 850 ℃ to 1000 ℃, the porosity of the samples prepared from cluster-like copper powder decreased from 44.3% to 20.5%. And their water absorption rate drops from 1.2 mm/s to 0.5 mm/s. In terms of mechanical properties, the tensile strength of samples prepared from copper powders with different morphologies all increased with the rising sintering temperature. Among them, the near-spherical powder showed the best tensile strength at all sintering temperatures. With the sintering temperature increasing from 850 ℃ to 1000 ℃, the tensile strength of the samples prepared from near-spherical powder increased from 8.7 MPa to 117.6 MPa.