Studies On Deuterium Resistance Of Al-Al₂O₃ Composite Coatings Prepared By Magnetron Sputtering

The retention and permeation of hydrogen and its isotopes is one of the key issues in fusion engineering.A tritium-resistant coating with a certain thickness on the surface of structural materials can effectively solve this problem.Al2O3 is widely used in the tritium-resistant coating because of its high hardness,high permeability reduction factor and good stability.In this thesis,Al2O3 coating and Al-Al2O3 composite coating were prepared on the surface of 316 L stainless steel by double target magnetron sputtering and inductively coupled plasma-enhanced magnetron sputtering(ICP-MS),and the ability to resist deuterium of the coating was tested.The research results are as follows:(1)A gas-driven deuterium permeation measurement platform was designed and made independently.The deuterium permeation calibration of the platform was carried out by the residual gas analyzer.Under the permeation conditions of deuterium gas pressure 0～100 kPa and permeation temperature 0～1000 ℃,the deuterium gas leakage rate was measured in the range of 7.75 ×10-8～1.3×10-6 Pa.m3/s.(2)By adjusting the combination of Al target and Al2O3 target,Al-Al2O3 double-layer coating and Al-Al2O3 fusion coating were prepared on 316 L stainless steel substrate by dual-target and dual-frequency magnetron sputtering.It was found that due to the deposition of Al-Al2O3 fusion coating by Co-Sputtering,an Al/Al2O3 transition layer was formed between Al and Al2O3,which effectively reduced the defects of interlayer microstructure,and made the Al-Al2O3 fusion coating have a denser interlayer structure than the Al-Al2O3 double-layer coating.The deuterium permeation test results showed that the deuterium resistance reduction factors of Al-Al2O3 fusion coating were two to three times more than that of Al-Al2O3 double-layer coating,and the deuterium permeation diffusion time of Al-Al2O3 fusion coating was 1/10 of that of Al-Al2O3 double-layer coating.As the penetration test temperature(823～1023 K)rises,it was found that the deuterium resistance reduction factor of Al-Al2O3 fusion coating increases significantly,from 8 to 72,which was caused by the transformation of amorphous Al2O3 to more denser γ-Al2O3 in high-temperature test.(3)Al2O3 coatings were prepared on 316 L stainless steel substrate by respectively using traditional magnetron sputtering and ICP-MS.It was found that the Al2O3 Island particles on the surface of the coating prepared by ICP-MS were small and less rough,but the Al2O3 coatings prepared by the two methods both were amorphous.After the deuterium resistance of the coating was tested,the results showed that the coatings prepared by the two methods did not visibly fall away and had no obvious cracks.The Al2O3 coating prepared by ICP-MS has a better ability to resist deuterium than the Al2O3 coating prepared by traditional magnetron sputtering.