The Role of Carbon in the Formation of Intrinsic Point Defects and Hydrogen Migration in α‐Al2O3‐Based Tritium Permeation Barriers

Abstract

The impurity effect is one of the major concerns for α‐Al2O3‐based tritium permeation barriers (TPBs). The effect of carbon, a common impurity element in α‐Al2O3, on the formation of intrinsic point defects and hydrogen migration behaviors is investigated by first‐principles calculations. It is found that carbon has a significant influence on the existing form, charge state, and relative stability in α‐Al2O3. In view of the hydrogen migration, carbon is not beneficial for the hydrogen permeation resistance in α‐Al2O3‐based TPBs because carbon can remarkably reduce the hydrogen migration barrier in α‐Al2O3.