Abstract:Ni/Al₂O₃ composites were prepared by hot pressing approach. The relationship between their microstructure, mechanical, dielectric and magnetic properties with Ni particle content was studied. By increasing the amount of, metal in the composite, the relative density and the bending strength decrease gradually. The possible reason is that non-wetting between Ni and alumina in the preparation results in weak adhesion of the Ni/Al interface. For the composites, the maximum fracture toughness is 6.4 MPa∙ m^1/2, which is about 25% higher than that of pure alumina ceramic. The increase in toughness of the Ni/Al₂O₃ composites is due to the deformation of nickel particles. The complex dielectric constant measurements indicate that the real part and the imaginary part increase greatly with the Ni content in the frequency range of 8.2−12.4 GHz. The real part and the imaginary part of complex permeability of the composites also increase with increasing Ni content.

Key words: Al₂O₃/Ni composites; dielectric property; magnetic property; mechanical property