Abstract
In this study, products obtained using Cu-Ni alloy powder and a Cu, Ni powder mixture in injection molding were compared. Both the alloy powder and the powder mixture were composed of 69.4 mass% Cu and 30.6 mass% Ni. Both feedstocks were composed of 56.0 vol% metal powder and 44.0 vol% organic binder. The binder system consisted of 25.0 vol% polybutylmethacrylate (PBMA), 35.0 vol% ethylene-vinyl acetate copolymer (EVA), and 40.0 vol% paraffin wax (PW) for both feedstocks. Sintered bodies of Cu-Ni alloy were produced from Cu-Ni alloy powder or Cu, Ni powder mixture using metal injection molding (MIM) technology. In nitrogen sintering, the density of sintered bodies produced using the Cu, Ni powder mixture was higher than that of sintered bodies produced using the Cu-Ni alloy powder. In vacuum sintering, the density of sintered bodies produced using the alloy powder was higher than that of sintered bodies produced using the powder mixture. Contents of oxygen and carbon in sintered bodies, and density depended on hydrogen treatment temperature. The maximum density, tensile strength and Vickers hardness (Hv) of sintered bodies produced using alloy powder were 8.39 g⋅cm-3, 213 MPa and 56.9-87.2, respectively. On the other hand, those of sintered bodies produced using the powder mixture were 8.36 g ⋅CM-3, 199 MPa and 86.9-123, respectively.
