Effect of Sulfuric Acid Addition on the Aluminum AC Etching in HCl Solution

염산용액내에 황산 첨가에 의한 알루미늄의 교류에칭 특성

  • Kim, Hangyoung (Department of Chemical Engineering, Inha University) ;
  • Choi, Jinsub (Department of Chemical Engineering, Inha University) ;
  • Tak, Yongsug (Department of Chemical Engineering, Inha University)
  • 김행영 (인하대학교 공과대학 화학공학과) ;
  • 최진섭 (인하대학교 공과대학 화학공학과) ;
  • 탁용석 (인하대학교 공과대학 화학공학과)
  • Received : 1997.03.12
  • Accepted : 1998.04.10
  • Published : 1998.08.10

Abstract

When sulfuric acid was added in HCl etching solution, corrosion of aluminum metal was inhibited by the chemical adsorption of sulfate ions. In the presence of $SO_4^{-2}$, cyclic voltammetry showed that the protective oxide film was formed on the inner surfaces of etch pits and, pit density was increased by nucleation on both the aluminum surface and the pits inside. Structure and distribution of etch pits found in AC etching of aluminum were strongly influenced by the concentration of $SO_4^{-2}$ and the amount of cathodic pulse charging. Below $0.8mC/cm^2$ of cathodic pulse charging, oxide films formed inside actively dissolving pits indicated the higher resistance to pit nucleation as the concentration of $SO_4^{-2}$ increases. However, the structural change of oxide films occurred above the $0.8mC/cm^2$ charging and the effect of $SO_4^{-2}$ was minimized, and it resulted in the rapid formation of etch pits.

Keywords

Aluminum;AC Etching;Sulfuric Acid;Oxide Films

Acknowledgement

Supported by : 한국과학재단

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