The investigation of sintering temperature and Ni interlayer effects on diffusion bonding in inserted metal injection molding

Metal injection molding (MIM) is a combination of powder metallurgy and plastic injection molding technologies. This method consists of four main steps: preparation of feedstock, injection molding, debinding and sintering. In inserted metal injection molding (IMIM), the feedstock is injected on a preformed wrought insert to fabricate a multi-functional specimen. In the present work, the insert was made of 1050 carbon steel, coated by nickel (Ni) interlayers with thicknesses of 10, 20 and 30 mu m, on which 316 L feedstock was injected. The injected specimens were debound, and then sintered at four different temperatures of 1260, 1300, 1340 and 1380 degrees C. The effects of sintering temperature and interlayer thickness on diffusion bonding were evaluated by shear strength measurement. As a result, the specimen sintered at 1300 degrees C with an interlayer having a thickness of 30 mu m exhibited the highest shear strength of 238 MPa, while the lowest strength, 170 MPa, was achieved for specimen sintered at 1260 degrees C having no interlayer.