open access

https://hdl.handle.net/2115/62192

Mott-Schottky Plot of the Passive Film Formed on Iron in Neutral Borate and Phosphate Solutions

英語

passivation

1987-06

The Electrochemical Society

J. Electrochemical Society

134(6)

1352-1357

The semiconductive properties of the passive film formed on iron were investigated by measuring the impedance of passivated iron electrodes in neutral borate and phosphate solutions. Mott-Schottky type of plot was applied to the impedance data to obtain the donor density ND and the flatband potential VFB as a function of film formation potential, oxidation time, and ion species present in the solution. The value of ND obtained for the passive film is in the range of 1×10^26-2×10^27m^-3 and decreases with increasing formation potential and oxidation time, indicating that the structural and electronic defects in the passive film decrease with increasing film thickness. The value of ND of the passive film formed in phosphate solution is greater than that in borate solution. From the fact that when the electrolyte was changed from borate to phosphate solution ND increased from the value in borate solution to the value in phosphate solution in a time period of about 10^3s, it is evident that phosphate ions penetrate into the passive film producing a large number of defects.

学術雑誌論文

Version of Record

© The Electrochemical Society, Inc. 1987. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in J. Electrochem. Soc. 1987 volume 134, issue 6, 1352-1357.

0013-4651

1945-7111