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Full-Text Articles in Physical Chemistry

Comparative Studies On The Deterioration Process Of Organic Coatings Under Immersed And Cyclic Wet-Dry Conditions By Eis, Yu-Nan Li, Jia Wang, Wei Zhang Nov 2010

Comparative Studies On The Deterioration Process Of Organic Coatings Under Immersed And Cyclic Wet-Dry Conditions By Eis, Yu-Nan Li, Jia Wang, Wei Zhang

Journal of Electrochemistry

Under the immersed and wet-dry cyclic conditions,the deterioration processes of the organic coatings on carbon steel surface have been comparatively studied by using electrochemical techniques.The wet-dry cycles were carried out in the alternating conditions of 12 h by immersing in a 3.5% sodium chloride solution and drying at 25 ℃ and 50% RH.Coating resistance,Rf,coating capacitance,Cf,and double layer capacitance,Cd,were monitored continuously and separately under above two conditions.The percentages of the intenfacial active area,Aw,were estimated from the obtained double layer capacitance,Cd.According to the EIS characteristics,the entire deterioration processes under above two mentioned conditions can be divided into three main stages,consisting of the …


Electrochemical Behaviors Of Organic Coating/Matal Substrate Under Simulated Deep Sea Environment Partⅰ.Effects Of Seawater Pressure On Transportation Behavior Of Water Through Coating And Coating′S Protective Performance, Bin Liu, Zhi-Gang Fang, Tao Wang, Hong-Bin Wang Nov 2010

Electrochemical Behaviors Of Organic Coating/Matal Substrate Under Simulated Deep Sea Environment Partⅰ.Effects Of Seawater Pressure On Transportation Behavior Of Water Through Coating And Coating′S Protective Performance, Bin Liu, Zhi-Gang Fang, Tao Wang, Hong-Bin Wang

Journal of Electrochemistry

By means of electrochemical impedance spectroscopy(EIS),the electrochemical behaviors of organic coating/metal substrate were studied under simulated deep sea environment in the laboratory.Effects of seawater pressure on the transportation behavior of water through coating and the protective performance of coating were analyzed.The experimental results showed that,compared to normal pressured seawater,there were different impedance characteristics of coating in 3.5 MPa pressured seawater.The main observations were that high seawater pressure accelerated the process of water uptake and invalidation of coating,increased water absorption,and lowered the anti-corrosion property of coating.


Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang Nov 2010

Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang

Journal of Electrochemistry

This study detailed the atmospheric corrosion behaviour of sintered NdFeB(M35) in a simulated marine atmosphere with 80% relative humidity(RH).The dissolution and subsequent reaction of NaCl particles cause the attack of NdFeB.The corrosion presented three representative types:if the electrolyte covered magnetic phase and Nd-rich phase,the Nd-rich phase was corroded firstly due to galvanic effect;if the electrolyte covered magnetic phase,magnetic phase was corroded along the grain boundary;if the electrolyte located near the position of defects,corrosion progressed along with the defect because of low concentration of oxygen inside the defect.With corrosion progressing,local corrosion areas were mutually connected,with Nd-rich phase and grain boundary being …


Eis Study On The Change Of Resistance And Water Absorption During The Failure Graduation Of Inorganic Zinc-Rich/Epoxy/Aliphatic Polyurethane Composite Coatings, Shao-Ping He, Jin-Ping Xiong, Yu-Ming Tang, Yu Zuo Nov 2010

Eis Study On The Change Of Resistance And Water Absorption During The Failure Graduation Of Inorganic Zinc-Rich/Epoxy/Aliphatic Polyurethane Composite Coatings, Shao-Ping He, Jin-Ping Xiong, Yu-Ming Tang, Yu Zuo

Journal of Electrochemistry

The failure process of inorganic zinc-rich/micaceous iron oxide epoxy/aliphatic polyurethane composite coatings in 3.5% NaCl solution under ultraviolet radiation(UV) was studied with Electrochemical Impedance Spectroscopy(EIS).The result shows that the protective property of the coating was enhanced with the increase of total coating thickness,but the degree of improvement reduced gradully as the coating thickness increased.The shielding effect of the micaceous iron oxide epoxy was mainly reflected in the initial period of the service process,while in later period the coating performance largely depended on the zinc-rich primer.The change of the water uptake in the composite coating presented a 'three-stage' characteristic.The thinner the …


Measurement And Wavelet Analysis Of The Electrochemical Noise Of Rebar Steel In Simulated Concrete Pore Solution, Rong-Gang Hu, Chen-Qing Ye, Shi-Gang Dong, Chang-Jian Lin May 2010

Measurement And Wavelet Analysis Of The Electrochemical Noise Of Rebar Steel In Simulated Concrete Pore Solution, Rong-Gang Hu, Chen-Qing Ye, Shi-Gang Dong, Chang-Jian Lin

Journal of Electrochemistry

Electrochemical noise ( ECN) measurement can provide information about both corrosion rate and corrosion type while inflicting no perturbation on the studied system. The ECN data of steel rebar in SPS with different amount of Cl-were collected and treated by discrete wavelet transformation to evaluate the contribution from transients in different frequency in the overall signals. Energy distribution plot( EDP) indicated in SPS with 0. 0001 mol/L NaCl,the transients with time constant between 16 ~ 32 s were found to be predominant over other processes; while in SPS with higher Cl-concentration,the trend toward active corrosion became the main process. It …