Study Of Corrosion And Inhibition Of Copper Clad Laminate And Reinforced Concrete

Part 1. Study on the Corrosion Behavior of Copper Clad LaminateElectronic materials are the foundation and precursor for the modern information technologies. As the support and the joint of the electronic components, corrosion of copper on the surface of copper clad laminate (CCL) may cause failures of electronic devices or equipments in practical services. In order to enhance the corrosion resistance of copper and its alloy, the corrosion behavior of copper electronic materials in given environments has been widely studied. In this work, we emphasized to study the corrosion behavior of CCL in NaCl solution by electrochemical techniques, combining in situ measurement of Raman spectroscopy. The main results are summaried as follows:(1) It is indicated, by linear polarization measurement, that the CCL in NaCl solution shows a lower corrosion resistance compared with pure copper in the same condition. The addition of some elements in pure copper may improve the mechanical property for CCL, but it results in lowering corrosion resistance for the copper alloy, besides, the process of CCL manufacturing may also affect its corrosion resistance.(2) The mechanism of anodic and cathodic process has been identified by cyclic voltammetry. The two oxidation peaks represent the formation of two oxides in different valent states respectively, and the"anodic current hump"on the reverse sweep denotes the process of Cu→Cu(Ⅰ) in the passive film. In other words, in the cathodic polarization the dissolution and reparation process of the passive film formed during the anodic process occur dynamically. The cathodic peak is attributed to the reduction of Cu(Ⅰ).(3) At low polarization potential, the CCL dissolves through the formation of CuCl2-, which may be a determinative step in the anodic process. And when the polarization potential increases, a porous film containing CuCl forms on the CCL surface, and the transportation of Cl- in the film becomes a controlling step in the corrosion process. An inductive loop at low frequency was observed in the EIS measurement, which can be explained by the modulation of CuCl film due to the competition between dissolution and growth processes of the Cu passive film on CCL surface.(4) A correlation of the adsorption of chloride ion on the CCL surface during the corrosion process and the electrode potential has been proved by the in situ measurement of laser Raman spectroscopy. With the increase of polarization potential, the process of desorption and adsorption of chloride ion and formation of corrosion products can be in situ followed on the CCL surface.Part 2. Study on the Corrosion and Inhibition of Steel/ConcreteThe inhibition of MFP(sodium monofluorophosphate)on rebar in alkaline solution containing chloride ion has been studied by electrochemical techniques, and Fourier Transform Infrared Spectroscopy in the Multiple Internal Reflection mode (FTIR-MIR) has been adopted to investigate the transportation behavior of water and MFP in the concrete. Some preliminary conclusions can be drawn-out as the follows:(1) The inhibition of MFP on rebar in alkaline solution containing chloride ion is studied by the electrochemical impedance spectroscopy (EIS) and electrochemical polarization. The equivalent circuit analysis was established to explain the EIS measurements and to further understand the corrosion and inhibition mechanisms of rebar in different immersion period. The inhibition of MFP changes with the immersion time, MFP and Cl- concentration in the solution. In the 0.1 mol/L NaCl solution, addition of 5% MFP for immerging 1d shows the best inhibition effect.(2) Fourier Transform Infrared Spectroscopy in the Multiple Internal Reflection mode (FTIR-MIR) has been developed to in situ investigate the transportation behavior of water and MFP in concrete for the first time in this work. It is found that the concrete thickness and cement/sand percentage play important effect on the transportation behavior of water and MFP in concrete. The penetration process of water and MFP in concrete becomes lower with the time, and their penetration rates are determined by the thickness and density of concrete layer.