A novel two-step field-assisted sintering method to prepare (MgCoNiCuZn)O high entropy oxide

A two-step sintering experiment of (MgCoNiCuZn)O high entropy oxide was performed to lower the flash onset temperature and shorten the process time. The flash onset temper-ature was efficiently minimized by regulating the first step heating process due to the variation of the conductivity and density of the compacts. The lowest onset temperature was only 307 degrees C at a 300 degrees C first step sintering. Subsequently, the as-sintered material with mainly rock-salt structure can be obtained in just 20 s soaking time after the field-assisted flash sintering procedure. The unusual densification was mainly caused by the higher configuration entropy and significant temperature gradients resulted from the preferential Joule heating of grain boundaries. This novel two-step sintering method would promote the rapid synthesize of high entropy oxides.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

A two-step sintering experiment was conducted to reduce the flash onset temperature and shorten the process time of (MgCoNiCuZn)O high entropy oxide. The flash onset temperature was effectively minimized by adjusting the first step heating process, resulting from the variation in conductivity and density of the compacts. The lowest onset temperature achieved was 307 degrees C at a 300 degrees C first step sintering. Subsequently, the as-sintered material with primarily rock-salt structure was obtained in just 20 s soaking time after the field-assisted flash sintering procedure. This novel two-step sintering method is expected to facilitate the rapid synthesis of high entropy oxides.