Investigation Of Preparation And Hydrogen Permeation Properties Of Alumina/Zirconia Composite Coating

Stainless steel is widely used in hydrogen related field as structural material. Hydrogen has high permeability in structural materials, thus it can cause severe hydrogen embrittlement. Moreover, the permeation and loss of hydrogen isotope tritium lead to radioactive contamination of the surrounding environment and loss of fusion fuel. In recent years, oxide coatings on surface of structural materials as hydrogen permeation barriers have become one the most promising techniques to solve the problem of hydrogen permeation. This work investigated the preparation of Al2O3/ZrO2composite coating by radio-frequency reactive magnetron sputtering and its performance. Sputtering parameters were optimized to deposit Al2O3, ZrO2and Al2O3/ZrO2coatings. The hydrogen permeation behaviors of these coatings were examined.(1) The thickness of the Al2O3coating prepared by optimum sputtering process was about236nm. The coating was compact and has typical columnar grains. The apparent hydrogen permeability of the Al2O3coatings:P=4.0×10-7exp(-110×103/RT) mol/(m·s·Pa0.5). The activation energy of hydrogen permeation of the coating is110kJ/mol. The hydrogen permeability reduction factor (PRF) values of the Al2O3coating were129-335at temperatures550-700℃.(2) The thickness of the ZrO2coating was about225nm. The coating was compact and homogeneous. The apparent hydrogen permeability of the ZrO2coatings: P=1.0×10-66exp(-116×103/RT) mol/(m·s·Pa0.5). The activation energy of hydrogen permeation of the coating is116kJ/mol. The PRF values of the ZrO2coating were117-374at temperatures550-700℃.(3) The thickness of the Al2O3/ZrO2composite coating was233nm and the face of the coating had high density and uniformity. The hydrogen permeation activation energy of the composite coating is132kJ/mol. The hydrogen permeability decrease factor was247-790during550-700℃. The hydrogen risistance performance of the Al2O3/ZrO2composite coating was much higher than those of the Al2O3and ZrO2-The thickness of the Al2O3/ZrO2composite coating was about233nm. The interface of the composite coating was compact. The apparent hydrogen permeability of the composite coatings: P=3.6×10-6exp(-132409/RT) mol/(m·s·Pa0.5). The activation energy of hydrogen permeation of the coating is132kJ/mol. The PRF values of the composite coating were247-790at temperatures550-700℃, much higher than the Al2O3coating. (4) The adhesion strength of the Al2O3/ZrO2composite coating was8.5N, higher than the value for the Al2O3coating,4.5N. The AlO2O3coating had apparent cracking on the surface after hydrogen permeation test while the surface of the Al2O3/ZrO2composite coating had no obvious change. The thermal stability of the Al2O3/ZrO2composite coating was higher than the Al2O3coating.