New horizons through atmospheric pressure chemical vapor deposition of aluminum for corrosion protection applications

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• 作者：Frank BaerholdWilhelm KarnerDaniel SchweighoferSimon Oberhauser
• 会议时间：2013-06-01
• 关键词：coil coating ; continuous coil coating with aluminum ; corrosion protection ; aluminum ; aluminum-zinc ; diffusion layers ; chemical vapor deposition ( CVD) ; atmospheric pressure metal organic CVD ( AP MOCVD)
• 作者单位：Frank Baerhold,Wilhelm Karner,Daniel Schweighofer(Andritz Metals,Vienna,Austria)Simon Oberhauser(InnCoa GmbH,Neustadt/Donau,Germany)
• 母体文献：第五届宝钢学术年会论文集
• 会议名称：第五届宝钢学术年会
• 会议地点：上海
• 主办单位：中国金属学会
• 语种：chi

摘要

Aluminum can be deposited on steel or metallic substrates by controlled thermal decomposition of aluminum organic compounds at temperatures between 250 - 370℃ under atmospheric pressure.The process is based on the Chemical Vapor Deposition (CVD) technique with higher deposition rates than typically achieved by conventional galvanic deposition of aluminum from aprotic solvents.The aluminization by means of Metal Organic Chemical Vapor Deposition ( MOCVD) procedures does not involve significant environmental hazard.The deposition does not involve any persistent organic or toxic chemicals.In this work we demonstrated that the MOCVD technique is suitable for coil coating lines as well as for other coating applications like coating of inner surfaces.The resulting Al-layers are closed and show a very even thickness distribution.Such layers provide a good corrosion resistance in neutral media containing chlorides.The determined corrosion rates of the Al-MOCVD coatings in these electrolytes are significantly lower compared to the widely used Zn-galvanic layers.To further improve the overall corrosion resistance,the Al-MOCVD coatings could be additional passivated either applying Cr (VI) - free or Cr-free scales.Overall corrosion resistance of the Al-MOCVD coatings can be even further enhanced by involving other elements like Zn in the generation of the coating.In this way corrosion attack at the locations where defects are present in the Al-coating can be eliminated.Such defects may come from cutting or even stone-chipping.To emphasize,as already indicated earlier,for producing such Al-Zn-coatings the temperature of deposition by the described technique is much lower compared to the hot dip deposition of the Al-Zn-Iayers,such as Galfan and Galvalume.