Corrosion protection of stainless steel by a self-assembled organosilane bilayer

Abstract

Purpose

The purpose of this paper is to construct a self-assembled double layer of organosilane on the surface of stainless steel and to investigate its corrosion inhibitive capability.

Design/methodology/approach

A monolayer of 3-glycidoxypropyltrimethoxysilane (GPTMS) was grafted onto an oxidized AISI 430SS (AISI 430 stainless steel) surface substrate from dry toluene solution. The hydrolysis of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDS) molecules was used to anchor a second organic layer from mixed water-ethanol solution. The adsorption behavior and corrosion inhibition properties of the monolayer and also the bilayer were investigated by potentiodynamic polarization, scanning electron microscope (SEM), Fourier transformed infrared spectroscopy (FTIR) and contact angle measurements.

Findings

The GPTMS/PFDS bilayer was successfully deposited onto the oxidized AISI 430SS surface. The optimal assembling time for the filming of the first GPTMS monolayer is 6 hours. Suitable values of pH and temperature of the PFDS self-assembly solution were pivotal to the successful deposition of the second layer. Compared to the GPTMS monolayer, the GPTMS/PFDS bilayer exhibited a significant enhancement of the corrosion inhibition performance of AISI 430SS in NaCl solution.

Research limitations/implications

The contact angle value measured on the bilayer-modified surface was somewhat lower than the reported value of a complete fluorinated surface. However, further optimization of the assembling condition is needed to obtain more orderly and denser films.

Originality/value

This paper provides useful information regarding the preparation of an organosilane bilayer on the surface of stainless steel and its corrosion inhibition properties in NaCl solution. It illustrates potential application prospects of GPTMS/PFDS bilayers for surface treatment of stainless steel.

Citation

Wang, H., Li, M., Qu, J., Cao, Z., Chen, G. and Zhou, Y. (2014), "Corrosion protection of stainless steel by a self-assembled organosilane bilayer", Anti-Corrosion Methods and Materials, Vol. 61 No. 5, pp. 307-313. https://doi.org/10.1108/ACMM-06-2013-1273