| Summary: | In the present research, an advanced Al composite reinforced with open-cell nickel foam (OCNiF) was produced using pre-compressed and Spark Plasma Sintering (SPS). For this purpose, open-cell nickel foam with 10 PPI was placed in a mold then the open-cell nickel foam was filled with pure Al powder and pre-compressed. The initial tablet was sintered at 420 °C under the load of 40 MPa. Afterward, the parts were annealed at 470 °C for two, four, and 8 h. Microstructural investigations was carried out by Field Emission Scanning Electron Microscope (FE-SEM) and X-ray diffraction (XRD). The results showed a complementary process for sintered particles, which became more complete with increasing time of annealing stemming from diffusion. Evaluations showed that the Al3Ni phase began to nucleate after 4 h of annealing at the Al/OCNiF interface. The mentioned phase stabilized and reached to 3 % by weight through annealing After 8 h. Annealing increased the hardness of the substrate by more complete sintering. The hardness of Al3Ni and Al3Ni2 phases increased to 503 and 647 Vickers, respectively. The polarization test showed that the corrosion resistance first increased and then decreased during annealing compared to the SPS sample. Ni affected the development of the protective layer to prevent the pitting corrosion. However, as the annealing time increased, the corrosion current decreased, which was due to the absence of Ni in the protective layer and the formation of corrosion microcells due to the formation and growth of Al3Ni and Al3Ni2 phases.
|
|---|