Multi-layer structured AlN/Er2O3 coating: Enhanced thermal stability and hydrogen isotope permeation resistance.

AlN/Er 2 O 3 multi-layer coatings, as a novel hydrogen isotope permeation barrier for nuclear reactor and hydrogen energy field, were prepared by magnetron sputtering coupled with metal-organic decomposition on the surface of reduced activation ferrite/martensitic steel. The thickness of the Er 2 O 3 layers was adjusted by spin coating several times, the adhesion of the layers was tested with a micron scratch tester, and the microstructure and surface composition of the layers were analyzed by TEM and XPS. The results indicate the absence of evident crack holes on the coating surface, uniform distribution of elements without segregation, and satisfactory densification. In comparison with the individual Er 2 O 3 coating, the multi-layer coating incorporating AlN as the interlayer exhibits enhanced adhesion strength, which could effectively mitigate the thermal mismatch phenomenon of Er 2 O 3 under high temperature conditions. Electrochemical hydrogen permeation and high temperature gas pressure driven deuterium permeation tests demonstrated that the permeability resistance of the AlN/Er 2 O 3 coating does not linearly increase with its thickness. The hydrogen permeation reduced factor of the coating reaches its maximum value when the thickness of the Er 2 O 3 coating is 1500 nm. [ABSTRACT FROM AUTHOR]