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文献 岳仑仑.

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Presentation on theme: "文献 岳仑仑."— Presentation transcript:

1 文献 岳仑仑

2 Zr-Al bilayer Anodic A1-Zr bilayer samples Zr: 0.5 um thick
Al:83 nm thick

3 Anodizing behaviour Voltage-time behaviour dunng anodizing of the A1-Zr bdayer at a constant current density of 5 mAcm -2in 0.1 M ammonium pentaborate solution at 25 °C due to the presence of an air-formed film

4 150 V at 5 mA cm -2 m 0.1 M ammonium pentaborate solution
amorphous A2O3 layer, about 132 nm thick zirconium layer partially oxidized to form a crystalline ZrO2 layer Polycrystalline ZrO2 with grain sizes up to about 20 nm.

5 amorphous A1203 layer to a depth of about 94 nm from the anodic alumina surface.

6 The oxidation behaviour of the super-imposed metallic layers was related to the ionic resistivities to the passage of a given anodizing current of the anodic oxides of the deposited metallic layer and substrate metal. the systems are unstable during anodizing when the anodic oxide of the deposited layer is more resistive than that of the substrate metal.

7 the lower resistivity anodic oxide of the substrate metal
the lower resistivity anodic oxide of the substrate metal. Thereafter, the anodizing current flows preferentially though the holes and the anodic oxide of the deposited metallic layer ,such as A1 on Ta , A1 on Nb Despite the outer anodic A1203 layer being more ionically resistive than the tuner anodic ZrOz layer, the "resistivity criterion" can be applied only for systems where the anodic oxides of the deposited metallic layer and substrate metal are both amorphous.

8 Transport processes during anodizing of the AI-Zr bilayer

9 Conclusions anodizing of zirconium covered by a thin, continuous layer of aluminium leads to development of an outer layer of amorphous alumina and an inner layer of crystalline anodic zirconia. an amorphous anodic film is present above a crystalline anodic film, the underlying oxide of low ionic resistivity does not penetrate locally, in the form of fingers, the outer layer of high resistivity anodic oxide.

10 Incorporation and mobility of zinc ions in anodic alumina films

11 Experimental A1-0.2 at% Zn alloy 35 nm thick
purity aluminium substrate constant current density

12 Basic For anodizing of aluminium at 100% current efficiency, about 40% of the film thickness is formed at the film/electrolyte interface, the remainder forming at the metal/film interface AI-Cu , AI-Ti , AI-W and AI-Zn prior oxidation of the aluminium atoms and the accumulation of the alloying element atoms in the alloy at the alloy/film interface occur.

13 the presence of the air-formed film at the alloy surface
the prior oxidation of aluminium on an electropolished AI-0.9 at% Zn alloy is terminated upon achieving an average enrichment of zinc; determined experimentally no 'incorporation of zinc ions into the anodic film is expected

14 Conclusions zinc atoms are accumulated in a layer of alloy, about 2 nm thick, just beneath the anodic film as a consequence of prior oxidation of the aluminium atoms. No zinc ions are incorporated into the anodic aIumina film during anodizing of the alloy. When the alloy film is almost totally consumed by anodizing, zinc atoms in the enriched alloy layer are oxidized and incorporated immediately into the anodic film as a result of the presence of an air-modified , electropolishing film on the aluminium substrate. Then zinc ions migrate outwards; the migration rate of the zinc ions is about 2.3 times that of A13+ ions.

15 工作计划 Al的厚度100nm,再次尝试光刻后选择性阳极氧化,进行图形和非图形阳极氧化实 验 使用热氧化片阳极氧化,用SEM观察分层情况
调整一下电流密度,观测阳极氧化结果 XRD分析


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