Nanophase and superfine cemented carbides processed by powder injection molding

Two commercial superfine and one innovative nanophase cemented carbide powders were used in this study. They cover straight and complex grades of cemented carbides. The nanophase cemented carbides are characterized by a combination of high hardness and strength. However, the nanophase cemented carbides do not have a favorable moldability. The as-received nanophase particles are agglomerated hollow balls. Therefore, milling was used on the as-received nanophase powder to form a particle suitable for injection molding. Even so, manufacture of nanophase cemented carbides via powder injection molding (PIM) is highly challenging. Several processing parameters affect the success, including powder moldability, binder chemistry, mixture homogeneity, molding parameters, debinding cycle, and sintering densification level. Binder-related factors were the focus of this study, including binder chemistry, binder-powder compatibility, feedstock preparation, molding conditions, and binder removal after molding. (C) 1998 Elsevier Science Ltd. All rights reserved