Fabrication of a novel high electrical conductivity Si3N4 matrix composite with Cu three-dimensional network structure by spark plasma sintering

Abstract

Silicon nitride (Si 3 N 4 ) ceramic matrix conductive composite materials have shown great promise as conductive layer materials for electrical transmission components. However, existing conductive phases struggle to form a three-dimensional (3D) interconnected network in Si 3 N 4 matrix, resulting in poor electrical conductivity . This study proposed a spark plasma sintering (SPS) process utilizing Si 3 N 4 as the substrate and Cu particles as the reinforcement phase to fabricate a novel electrical conductivity Si 3 N 4 /Cu composite material. The results indicated that the diffusion of Si atoms in Si 3 N 4 facilitated the formation of copper silicide (Cu i Si) interface between the two constituents during sintering, creating a strong chemical bonding for high conductivity. Simultaneously, composite materials with optimized Cu content formed a 3D interconnect network structure, providing a continuous path for electrical conduction. At Cu content of 30 vol%, the Si 3 N 4 /Cu composite exhibited a satisfying electrical conductivity of 295.37 S/m, which was 14 orders of magnitude higher than that of Si 3 N 4 . The composites also demonstrated a percolation phenomenon, with a theoretical percolation threshold of Cu particles at just 0.1 vol%, an order of magnitude lower than that of carbon reinforcement particles . Furthermore, an integrated design featuring external insulation and internal conductivity was achieved by wrapping a Si 3 N 4 insulation layer around the conductive Si 3 N 4 /Cu composites. The fabricated insulation layer exhibited higher resistivity (1.12×10 14 Ω) and a lower wear rate (1.3×10 −6 mm 3 /N·m) compared to some contemporary insulation ceramics, while the conductive layer had a lower calorific value , making them excellent candidates for electrical transmission component materials.

Topics & Concepts