Repeatability and Reproducibility of Electrical Measurements of Spark-Plasma-Sintered Alumina-SiCw Composites

Al2O3-SiCw ceramic composites are often assumed to be electrically insulating, but with the addition of SiCw as a semi-conducting filler phase, the overall electrical behavior can transition from insulating to conducting when a critical amount of SiCw is added; a process commonly referred to as percolation. Composites are inhomogenous in nature, and thus electrical measurements can be used to measure and quantify the overall electrical behavior of composites as well as differences between samples densified using identical sintering conditions and compositions. In this paper, impedance spectroscopy based measurements were used to capture percolation in spark-plasma-sintered Al2O3 - SiCw of varying SiCw volume content and determine the percolation threshold where the insulating to conducting transition in behavior is observed. Additionally, statistical analysis was performed on the measurements to determine and quantify the repeatability of electrical measurements done on the same sample, as well as reproducibility between samples of the same composition over a given frequency range. This paper introduces a new approach to represent errors in frequency dependent electrical measurements, allowing for an assessment of the homogeneity of a composite by capturing the variance in the insulating or conducting processes of the material.