The protection of TDPA deposited from mixed solutions with different water/ethanol ratios for aluminum alloy against corrosion in NaCl solution
Abstract
Purpose
The purpose of this paper is to investigate the effect of water content of assembly solution on the adsorption behavior and corrosion protection performance of 1–tetradecylphosphonic acid [TDPA, CH3(CH2)13P(O)(OH)2] films on aluminum alloy surface in NaCl solution.
Design/methodology/approach
Self-assembled monolayers (SAMs) of TDPA were prepared on the 2024 aluminum alloy surface in TDPA containing ethanol-water solutions with different water contents. The adsorption behavior of the SAMs on the alloy surface and their corrosion protection properties in a 3.5 per cent NaCl solution were characterized by potentiodynamic polarization scan, Fourier-transformed infrared spectroscopy (FTIR) and atomic force microscopy (AFM).
Findings
The FTIR results demonstrated that the TDPA molecules were successfully adsorbed on the 2024 aluminum alloy surface, and the density of the SAMs increased with the increasing water content in the assembly solution. The electrochemical studies and corrosion morphologies observed by AFM showed that the optimal condition is 2 h of assembling in solution B or solution C. The corrosion inhibition efficiency values follow the order solution B ≈ solution C > solution A at the first 2 h assembly and solution B > solution C > solution A while the assembly time exceeded 2 h. The dependence of corrosion inhibition performance of the SAM on the water content and on the assembly time is related to the balancing of competition between TDPA adsorption and dissolution of the alloy oxidation film.
Originality/value
It illustrates potential application prospects of TDPA for surface treatment of aluminum alloy. Via the comparison with our previous work, this paper provides useful information regarding the difference of corrosion inhibition properties of organic phosphonic acid for aluminum alloy between in neutral and in acid solution.
Keywords
Acknowledgements
The authors gratefully acknowledge the financial support of the Youth Foundation of Hubei Provincial Education Bureau (Grant No. Q20120110) and the National Natural Science Foundation of China (Grant No. 51001045).
Citation
Jun-e, Q., Geng, C., Hai-ren, W. and Zhi-yong, C. (2017), "The protection of TDPA deposited from mixed solutions with different water/ethanol ratios for aluminum alloy against corrosion in NaCl solution", Anti-Corrosion Methods and Materials, Vol. 64 No. 2, pp. 233-240. https://doi.org/10.1108/ACMM-09-2015-1576
Publisher
:Emerald Publishing Limited
Copyright © 2017, Emerald Publishing Limited