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Hydrogen isotopes permeation barriers (HIPB) play an important role in reducing hydrogen isotopes permeation and leakage in hydrogen energy and thermonuclear fusion energy. In this study, the Al 2 O 3 -HIPB were prepared on 316L stainless steel by RF magnetron sputtering. The impacts of coating thickness and annealing temperature of as-deposited coatings on deuterium permeation reduction factor (D-PRF) are studied in detail. With increasing thickness of coatings from 0.2 μm to 1.6 μm, the D-PRF did not rise significantly, which indicated that coating surface, for thin coatings, played more important role in impeding deuterium permeation than coating interior. As a result of further crystallization and grain growth, the 700 °C-annealed Al 2 O 3 coatings had stronger ability to impede deuterium permeation than 600 °C-annealed Al 2 O 3 coatings. This further proofs that grain boundaries may be a short-cut path for deuterium diffusion in Al 2 O 3 coatings. The D-PRF drastically decreased when the annealing temperature reaches 800 °C, which might be ascribed to the new phases form and the coating cracks appearance after 800 °C annealing. [ABSTRACT FROM AUTHOR]

In hydrogen energy and thermal fusion energy, hydrogen isotopes permeation barriers (HIPB) are used to reduce hydrogen isotopes permeation, which may result in hydrogen isotopes leak and construction materials brittleness. Here, we made Er 2 O 3 HIPB by magnetron sputtering and studied the relation between deuterium-permeation reduction factor (D-PRF) and coating thickness, micro-morphology. The 0.2 μm Er 2 O 3 coatings can reduce deuterium permeation by 1/10 ∼ 1/20 at 600 °C ∼ 300 °C. However, the reduction ability decreases gradually with the increase in coating thickness when the coatings are thicker than 0.2 μm. The reason may be ascribed to the deuterium invasion in deuterium permeation test. After deuterium invasion into coatings, the coatings suffer intrinsic stress, thermal stress and expansion stress from deuterium invasion. As a result of grain size dependence on coating thickness in PVD-derived coatings, i.e. grains become coarse with increasing coating thickness, the sum of stresses in various type increases with increasing coating thickness. The coatings crack easily when they suffer more strong tensile stress. So, the damages of coatings become serious and D-PRF reduces with increasing coating thickness. [ABSTRACT FROM AUTHOR]

Composite coatings as Hydrogen Isotopes Permeation Barriers have seldom been studied. In this work, the Al 2 O 3 –Er 2 O 3 component composite HIPB were prepared on 316L stainless steel by radio frequency reactive magnetron sputtering. The deuterium permeation reduction factor (D-PRF), structure and nano-hardness of the Al 2 O 3 –Er 2 O 3 composite HIPB were investigated. The Er 4 Al 2 O 9 (012), (023) diffraction peaks appeared. The D-PRF of 1.2 μm Al 2 O 3 –Er 2 O 3 composite HIPB could reach 160 at 600 °C, the D-PRF was 210 at 450 °C and increased sharply to 1380 at 250 °C. The coatings kept dense during the deuterium permeation tests while the Er 4 Al 2 O 9 phases changed. The nano-hardness decreased from 9.55 GPa to 7.46 GPa after the deuterium permeation tests. It was inferred that the deuterium atoms invasion and formation of oxygen vacancies should be responsible for the performance and structure changes of the Al 2 O 3 –Er 2 O 3 composite HIPB during deuterium permeation tests. [ABSTRACT FROM AUTHOR]