| Abstract: | A Ni-B_4C macroscopic diffusion welding couple and a Ni-15 wt% B_4C composite fabricated by spark plasma sintering(SPS) were used to understand the micro-scale diffusion bonding between metals and ceramics. In the Ni-B_4C macroscopic diffusion welding couple a perfect diffusion welding joint was achieved. In the Ni-15 wt% B_4C sample, microstructure analyses demonstrated that loose structures occurred around the B_4C particles. Energy dispersive X-ray spectroscopy analyses revealed that during the SPS process, the process of diffusion bonding between Ni and B_4C particles can be divided into three stages. By employing a nano-indentation test, the room-temperature fracture toughness of the Ni matrix was found to be higher than that of the interface. The micro-diffusion bonding between Ni and B_4C particles is quite different from the Ni-B_4C reaction couple. |
