A composite coating of GO-Al2O3 for tritium permeation barrier

•A new composite coating of GO-Al2O3 for tritium permeation barrier is prepared by the sol-gel method.•The toughness and deuterium permeation barrier performance of the Al2O3 coating is enhanced by adding the GO nanosheets.•Deuterium permeation reduction factor of the 0.5 wt% GO-Al2O3 composite coating increases about 9 times in comparison with the pure Al2O3 coating. To improve tritium permeation resistance and toughness of Al2O3 coating, a new graphene oxide (GO)-alumina (Al2O3) composite coating as tritium permeation barrier was designed in this paper. GO was added into Al2O3 to prepare the composite coating of GO-Al2O3 by a sol-gel method. The results showed that the deuterium permeation reduction factor (PRF) of 0.5 wt% GO-Al2O3 coating was higher than that of the pure Al2O3 coating at 500 ℃. It was related to the GO nanosheets blocking the diffusion of deuterium atoms in the Al2O3 coating and reducing the permeability. Meanwhile, the toughness of the 0.5 wt% GO-Al2O3 coating was enhanced by about 40 % than the pure Al2O3 coating. The reason can be speculated that GO nanosheets can prevent the cracks propagation in the composite coating of GO-Al2O3. This study could provide a new material of tritium permeation barrier for fusion reactors.