华南理工大学学报(自然科学版) ›› 2010, Vol. 38 ›› Issue (4): 76-82.doi: 10.3969/j.issn.1000-565X.2010.04.015

• 材料科学与技术 • 上一篇    下一篇

常温时添加剂对Ce-Mn转化膜的影响

张军军 李文芳 杜军   


  1. 华南理工大学 材料科学与工程学院, 广东 广州 510640
  • 收稿日期:2009-08-11 修回日期:2009-12-04 出版日期:2010-04-25 发布日期:2010-04-25
  • 通信作者: 李文芳(1954-),男,教授,博士生导师,主要从事材料表面工程的研究.E-mail:mewfli@scut.edu.cn E-mail:zjjhscn@163.com
  • 作者简介:张军军(1976-),男,博士生,主要从事材料表面工程的研究.
  • 基金资助:

    粤港关键领域重点突破(佛山专项)专项基金资助项目(2008Z012); 广东省重大科技专项(产业共性技术)基金资助项目(2009A08025002)

Influence of Additives on Ce-Mn Conversion Coating at Room Temperature

Zhang Jun-jun  Li Wen-fang  Du Jun   

  1. School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2009-08-11 Revised:2009-12-04 Online:2010-04-25 Published:2010-04-25
  • Contact: 李文芳(1954-),男,教授,博士生导师,主要从事材料表面工程的研究.E-mail:mewfli@scut.edu.cn E-mail:zjjhscn@163.com
  • About author:张军军(1976-),男,博士生,主要从事材料表面工程的研究.
  • Supported by:

    粤港关键领域重点突破(佛山专项)专项基金资助项目(2008Z012); 广东省重大科技专项(产业共性技术)基金资助项目(2009A08025002)

摘要: 为了提高常温下Ce-Mn转化膜在铝合金表面的成膜速度和耐腐蚀性能,在室温、pH=2的Ce(NO33和KMnO4的混合溶液中分别添加H3BO3、Zr(SO42、NaF、HF、NaBF4和Na2ZrF66种添加剂,研究添加剂对Ce-Mn转化膜的影响.通过光学显微镜、涡流测厚仪、点滴腐蚀法、Tafel极化曲线和交流阻抗等研究了膜的金相组织、厚度及耐腐蚀性能等;同时,通过SEM和EDS研究了氟化钠对膜的形貌和成分的影响.结果表明:氟化钠是较佳的常温成膜促进剂,常温下9 min就能成膜,相对于无添加剂的Ce-Mn转化膜,膜厚增加2.3倍,耐点滴腐蚀时间延长2.0倍,腐蚀电流密度降低至原来的1/3,膜电阻提高3.9倍:添加NaF后膜的铈含量从5.14%提高到8.59%,锰含量从7.70%提高到14.42%.

关键词: 铝合金, 成膜促进剂, Ce-Mn转化膜, 硝酸铈, 高锰酸钾, 耐蚀性能

Abstract:

In order to accelerate the coating formation and improve the corrosion resistance of Ce-Mn conversion coating on aluminium alloy at room temperature,six additives including H3BO3,Zr(SO42,NaF,HF,NaBF4 and Na2ZrF6 were respectively added in the mixed solution of Ce(NO33 and KMnO4,and the effects of these additives on the behaviours of Ce-Mn conversion coating were investigated.Then,the metallographic structure and thickness of the coating were analyzed by using an optical microscope and an eddy current thickness meter,respectively,and the corrosion resistance of the coating was discussed by dropping corrosion test,Tafel polarization curves and electrochemical spectroscopy(EIS).Finally,the effects of NaF on the morphology and composition of the coating were analyzed by means of SEM and EDS.The results indicate that,with the help of NaF,Ce-Mn conversion coating can be prepared at room temperature with a time consumption of only 9min,the thickness,anti-corrosion time,co-rrosion current density and impedance of the coating are respectively 3.3,3.0,1/3 and 4.9 times that of the coating without any additives,and the Ce and Mn contents of the coating increase from 5.14% to 8.59% and from 7.70% to 14.42%,respectively.It is thus concluded that NaF is an optimal additive for the formation of Ce-Mn coating.

Key words: aluminium alloy, film-forming accelerator, Ce-Mn conversion coating, cerium nitrate, potassium permanganate, corrosion resistance