Preparation techniques of metal clad fibres for corrosion monitoring of steel materials

Abstract

To fabricate metal clad optical fibres for corrosion sensing, we investigated and compared three techniques of preparing metal cladding on the surface of fibres with cladding removed. The first technique directly deposits iron on the fibre surface by physical vacuum deposition (PVD). The second technique uses nickel on the fibre under the control of a magnetic field in a vacuum environment (MFV). The third technique prepares silver on the fibre by chemical sputtering plating (CP). Finally corrosion-sensitive fibre samples with metal cladding treated as in the above three techniques are electroplated with the materials for monitoring. The metal cladding by the first technique achieved the best quality, and also the desirable material composition and structure as examined by x-ray diffraction analysis. The corrosion parameters of the first metal clad samples, including the change of open circuit potential E-corr and linear polarized resistance R-p with Cl- concentrations, were measured. The fibres prepared by the first technique are shown to satisfactorily monitor corrosion processes in our preliminary experiment.