Asynergistic inhibition study was carried out on an aluminium/copper galvanic coupling model in neutral aerated NaCl solution using scanning vibrating electrode technique(SVET).The approach allows the simulation of the local micro-galvanic cells of AA2024-T3 obtained from the potential difference between the intermetallic particles(IMPs)and the aluminium matrix.The inhibition effect of CeCl3 and 3-Amino-1,2,4-triazole-5-thiol(ATAT)was demonstrated by the reduction in the galvanic current density over Al and Cu surfaces.An improved inhibition from positive synergistic effect was revealed by the combination of the two inhibitors after 24 h of immersion,with the best inhibition recorded for Ce1.5ATAT3.5.Scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and time of flight secondary ion mass spectrometry(ToF-SIMS)were used to characterize the Ce-and ATAT-based complex film formed and to illustrate the mechanism of inhibition.
Inime Ime UdohHongwei ShiMohammad SoleymanibrojeniFuchun LiuEn-Hou Han
Self-assembled nano-phase silane-based particle coating was prepared through sol-gel technique.Tetramethoxysilane and 3-glycidoxypropyltrimethoxysilane were used as precursors for the self-assembled sol-gel coatings.The silane colloidal particle size was analyzed by laser particle size measurement.The results indicate that the particle size is in nano-scale and the diameter of particles deceases with increasing dilution times.Gel permeation chromatography proves that the relative molecular mass of macromolecule in a referenced sol solution is 1220-1240 amu.A simulation model was proposed to study the siloxane structure.Fourier transform infrared spectra of solution and film prove the disappearing of epoxy bond.The results of solid-state 13C and 29Si nuclear magnetic resonance experiments indicate the formation of Si-O-Si network.Potentiodynamic analysis shows that the self-assembled coating has excellent corrosion resistance.Salt fog tests prove that 2-methyl piperidine as inhibitor significantly improves the corrosion resistance of the self-assembled coating.
Cerium malate (CeMal) was tested as a corrosion inhibitor for AA2024-T3 in this work. Corrosion inhibition on bare AA2024-T3 indicated that the inhibiting effect was a result of the synergistic effect of cerium cations and maleic anions. The corrosion of AA2024-T3 was stagnated by greatly reducing the corrosion current when CeMal was present in NaCl solutions. CeMal was adsorbed on the surface of AA2024-T3 forming a protective film in the initial stage. Then, cerium cations transformed to cerium oxide/hydroxides, precipitating on the cathode sites to inhibit the further corrosion. The electrochemical impedance spectra results of the sol-gel coatings proved that CeMal was an effective corrosion inhibitor in the sol-gel coatings to provide corrosion protection for AA2024-T3.
Tian-Hui HuHong-Wei ShiTao WeiShi-Hua FanFu-Chun LiuEn-Hou Han
为了实现升级改造后各分散控制系统(distributed control system,DCS)与原DCS的数据交互,对DCS第三方通信接口与具体实现方法进行了研究。阐述了与DCS建立第三方通信的几种常见实现方法:硬接线实现、串口实现、用于过程控制的对象连接与嵌入技术(object linking and embedding for process control,OPC)实现,分析比较各种方法的优缺点,归纳总结各自适用场合,认为多种方式交叉应用的解决方案将在长时间内占据主流地位。
