Microstructure and Physical and Mechanical Properties of Si₃N₄/Ni Composite with Tree-Ring Imitating Structure

Although engineering ceramics are widely used in industry, its high brittleness is one of the main factors restricting its popularization. This paper was to synergistically improve the strength and toughness of engineering structural ceramics. A wood tree ring-like Si₃N₄/Ni composite was prepared with micron-sized powder of Si₃N₄ and high purity nickel wire via hot pressing sintering. The interface bonding between Si₃N₄ matrix and Ni wire in Si₃N₄/Ni composite was investigated, and the physical and mechanical properties of the composite were characterized. The results show that the interface between Si₃N₄ matrix and Ni wire in the composite is well bonded, and the wood tree ring-like material structure contributes to the strengthening and toughening of ceramic materials. The bending strength and fracture toughness of the composite are (989±87) MPa and (8.12±0.8) MPa·m^1/2, respectively. Compared with single-phase Si₃N₄, the physical and mechanical properties of Si₃N₄ ceramics are improved.