Gradient structure design of zinc oxide varistor microsphere composites for efficient electric field grading

Abstract Both the functionally graded material and the nonlinear conductive material can be used for grading electric fields. If a nonlinear conductive material with a gradient distribution can be designed according to the electric field distribution characteristics, better control of the electric field distribution will be achieved. In this paper, we realize switching field graded design of zinc oxide (ZnO) varistor microsphere composites in an epoxy resin matrix. Chopped glass fibers were added to a ZnO varistor microsphere/epoxy binary system to form a three-dimensional network. The volume fraction of glass fibers was altered to modify the density of the three-dimensional networks. Under the influence of gravity, the three-dimensional network composed of glass fiber realized layer-by-layer inhibition of the sedimentation of ZnO varistor microspheres, thereby creating a gradient distribution of the ZnO varistor microspheres. Thus, we realized gradient distribution design of the adaptive composites composed ZnO varistor microsphere.