Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (09): 2392-2396.doi: 10.3866/PKU.WHXB20100846

• ELECTROCHEMISTRY • Previous Articles     Next Articles

In situ Ellipsometric Study on the Initial Stages of Porous Anodization of Aluminum

LEI Jing-Lei, ZHANG Li-Na, LI Ling-Jie, ZHENG Sha, WANG Chao, XIE Zhao-Ming, ZHANG Sheng-Tao   

  1. College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, P. R. China
  • Received:2010-02-19 Revised:2010-04-18 Published:2010-09-02
  • Contact: LI Ling-Jie E-mail:LJLi@cqu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20603049, 20803097), Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China ([2007]1108-4) and Natural Science Foundation Project of CQCSTC (2008BB4174).

Abstract:

The initial stages of the anodization of aluminum are influential during the preparation of anodic aluminum oxide nanotemplates and provide an insight into their formation mechanism. The formation and development of both the barrier layer and the porous layer are involved. In this paper, in situ ellipsometric spectra with a high time-resolution were collected. To deconvolute the ellipsometric spectra, several optical models were extracted from the physical models of the Al-H2SO4 interface. Using these models and the effective medium approximation, detailed information about the composition and thickness of the Al2O3-Al interphase, Al2O3 barrier layer, and porous layer was acquired. Based on the deconvoluted results and the optical models, 4 stages of the porous anodization of aluminum, i.e., the barrier layer grows, pores form, pores enlarge, and pores grow at a stable rate, were clearly distinguished. Moreover, during the last stage the thickness of the porous layer changes linearly with time at a rate of 5.8 nm·s-1 while both the thickness of the barrier layer and the porosity of the porous layer change very little.

Key words: Aluminum, Anodization, Template, Spectroscopic ellipsometry, Effective medium approximation

MSC2000: 

  • O646.54