In this paper,A technique that preparing Al 2O 3 barrier film on surface of stainless steels (00Cr17Ni14Mo2 and 1Cr18Ni9Ti)
have been studied.In order to test the permeation behavior,hydrogen was used to simulate deuterium and tritium.Firstly,pack cementation aluminizing process had been adopted to form a aluminum rich layer on the surface of stainless steels.The aluminizing layer shows multiplayer characteristics which consists of inner layer (25 μm),external layer (5 μm) and transitional layer (30 μm).The good adherence can be seen between the sub-layers and the interface between the layer and substrate as observed by metallography.The weight concentration of the element Al in the aluminizing layer exceeds 30 mass %.Then
thermal oxidation processes were taken on the aluminized layer to form the Al 2O 3 film.It shows that an uniform and compact Al 2O 3 film is grown on the aluminizing layer.The film thickness is about 0.6μm when oxidized at 900℃ for 2 h in 2 0×10 -2 Torr oxygen pressure.In order to examine the hydrogen permeation property of the materials,the hydrogen permeation treatment were taken to both the aluminied and bare steds.Then the amount of hydrogen in the surface region of the steels was measured by elastic recoil detection (ERD) method.It was found that the content of hydrogen dropped gradually with the increasing distance to the surface.And the hydrogen content at the distance of 0 2 μm from the surface is 0 007 at% that is about the hydrogen content of the received
stainless steel.This implies that the hydrogen atoms can not diffuse through the formed Al 2O 3 barrier film.The aluminization plus oxidation to form the Al 2O 3 barrier film is an effective method for resisting the permeation of hydrogen and its isotopes.