Understanding and quantification of grain growth mechanism in ZrO_2 carbon nanotube composites

摘要

The high temperature grain growth behaviour of Y2O3 partially stabilised ZrO2 and ZrO2-CNT (0.5 and 2 vol%) composites was investigated in a series of isothermal experiments carried out between 1500 and 1800 degrees C. The grain growth activation energy was found to be 417 +/- 20 kJ mol(-1) for the ZrO2, which increased with the addition of CNTs to 509 +/- 41 and 497 +/- 17 kJ mol-1 for the 0.5 and 2 vol% composites respectively. A sintering exponent of 2 was observed for the ZrO2, corresponding to normal grain growth, whilst the nanocomposites showed a CNT drag dominated sintering mechanism, with exponents of 2.7 and 3.2 for the 0.5 and 2 vol% composites respectively. This work confirms and quantifies the direct influence of CNTs on the grain growth mechanism and activation energy of ZrO2-CNT composites. (C) 2017 Elsevier Ltd. All rights reserved.