Nickel Powder Filled Piezoresistive Composites Based on Field Emission and Quantum Tunneling Effect

The electrical electivity and its variation regularity under compression of cement-based composites with different kinds and contents of nickel powder were measured, and the particle shape and the surface morphology of nickel powder were observed to explore the generation mechanism of the conductivity and piezoresistivity of cement-based materials with nickel powders. The research results show that the conductivity and piezoresistivity of cement-based materials with 15, 20 and 25% ultrafine aristate spherical nickel powder increase orderly. The conductivity of cement-based materials with chain nickel powder is better than that of cement-based materials with spherical nickel powder, and the conductivity of cement-based materials with ultrafine aristate spherical nickel powder is better than that of cement-based materials with nickel powder with smooth surface. These findings indicate that the conductivity and piezoresistivity of cement-based composites with nickel powder is heavily dependent on the particle shape, surface morphology and content of nickel powder, and the favorable conductivity and piezoresistivity of cement-based materials with ultrafine aristate spherical nickel powder are caused by field emission and quantum tunneling effect.