Surface engineering of magnesium alloys requires adequate strategies, processes and materials permitting corrosion protection. Liquid formulations containing corrosion inhibitors often are to be optimized according to...Surface engineering of magnesium alloys requires adequate strategies, processes and materials permitting corrosion protection. Liquid formulations containing corrosion inhibitors often are to be optimized according to the demands of the respective substrate and following the service conditions during its application. As an interdisciplinary approach, a combination of several techniques for instantly monitoring or elaborately analyzing the surface state of magnesium was accomplished in order to characterize the performance of new adsorbing sustainable amphiphilic polymers which recently were developed to facilitate a multi-metal corrosion protection approach. The application of established techniques like Contact Angle measurements and X-ray Photoelectron Spectroscopy investigations was supplemented by introducing related and yet faster online-capable and larger-scale techniques like Aerosol Wetting Test and Optically Stimulated Electron Emission. Moreover, an inexpensive setup was configured for scaling the inset and the extent of degradation processes which occur at local electrochemical circuits and lead to hydrogen bubble formation. Using these analytical tools, changes of the surface state of emeried AM50 samples were investigated. Even in contact with water, being a moderate corrosive medium, the online techniques facilitated detecting surface degradation of the unprotected magnesium alloy within some seconds. In contrast, following contact with a 1 weight% formulation of a polymeric corrosion inhibitor, surface monitoring indicated a delay of the onset of degradation processes by approximately two orders of magnitude in time. Mainly based on the spectroscopic investigations, the corrosion inhibiting effects of the investigated polymer are attributed to the adsorption of a primary polymer layer with a thickness of a few nanometers which occurs within some seconds. Immersion of magnesium for several hours brings up a protective film with around ten nanometers thickness.展开更多
Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacry...Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization. [WT5HZ]展开更多
借助粒子视频显微镜(Particle Video Microscope,PVM)对水合物高压实验环路中的油包水乳状液混合以及水合物的生成、聚结过程进行了实验研究。结果表明:PVM设备可以清晰、定量、视觉化地检测到水合物的生成结晶过程以及实时颗粒/液滴的...借助粒子视频显微镜(Particle Video Microscope,PVM)对水合物高压实验环路中的油包水乳状液混合以及水合物的生成、聚结过程进行了实验研究。结果表明:PVM设备可以清晰、定量、视觉化地检测到水合物的生成结晶过程以及实时颗粒/液滴的粒径分布,并发现随着水合物的不断生成,其水合物颗粒会发生聚结,形成较大的水合物颗粒,随着反应的进一步进行,水合物颗粒粒径会表现为先增大后减小的趋势,这主要是由于水合物生成过程中的颗粒、液滴间的碰撞、聚集使得粒径增大,同时体系中增强的剪切作用和水合物颗粒表面润湿性的减小致使聚集的水合物颗粒又发生破碎所致;再则,实验过程中阻聚剂的加入对油水乳状液具有较好的乳化作用,使其水相较为均匀的分散到连续油相中,形成稳定、均一的乳状液体系,并且其分散相水滴的粒径要较不加剂情况下少;在水合物的形成过程中水合物颗粒间的聚并是导致水合物堵塞管道的主要原因。展开更多
基金Borders(Ciencia sem Fronteiras,proc.L.M.G.Goncalves 88888.021780/2013-00,L.C.Sanchez 88888.021800/2013-00 and S.Stamboroski 88888.020610/2013-00)Coordination of Improvement of Higher Education Personnel(CAPES-Brazil)and Consejo Nacional para Investigaciones Científicas y Tecnologicas de Costa Rica.(CONICIT)for the funding+1 种基金the German Federal Ministry of Economics and Technology(BMWi)under the ZIM programme(Zentrales Innovationsprogramm Mittelstand-ZIM)the“KABA”project(funding reference KF2139502 HA9)carried out with Straetmans High TAC GmbH
文摘Surface engineering of magnesium alloys requires adequate strategies, processes and materials permitting corrosion protection. Liquid formulations containing corrosion inhibitors often are to be optimized according to the demands of the respective substrate and following the service conditions during its application. As an interdisciplinary approach, a combination of several techniques for instantly monitoring or elaborately analyzing the surface state of magnesium was accomplished in order to characterize the performance of new adsorbing sustainable amphiphilic polymers which recently were developed to facilitate a multi-metal corrosion protection approach. The application of established techniques like Contact Angle measurements and X-ray Photoelectron Spectroscopy investigations was supplemented by introducing related and yet faster online-capable and larger-scale techniques like Aerosol Wetting Test and Optically Stimulated Electron Emission. Moreover, an inexpensive setup was configured for scaling the inset and the extent of degradation processes which occur at local electrochemical circuits and lead to hydrogen bubble formation. Using these analytical tools, changes of the surface state of emeried AM50 samples were investigated. Even in contact with water, being a moderate corrosive medium, the online techniques facilitated detecting surface degradation of the unprotected magnesium alloy within some seconds. In contrast, following contact with a 1 weight% formulation of a polymeric corrosion inhibitor, surface monitoring indicated a delay of the onset of degradation processes by approximately two orders of magnitude in time. Mainly based on the spectroscopic investigations, the corrosion inhibiting effects of the investigated polymer are attributed to the adsorption of a primary polymer layer with a thickness of a few nanometers which occurs within some seconds. Immersion of magnesium for several hours brings up a protective film with around ten nanometers thickness.
文摘Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization. [WT5HZ]
文摘借助粒子视频显微镜(Particle Video Microscope,PVM)对水合物高压实验环路中的油包水乳状液混合以及水合物的生成、聚结过程进行了实验研究。结果表明:PVM设备可以清晰、定量、视觉化地检测到水合物的生成结晶过程以及实时颗粒/液滴的粒径分布,并发现随着水合物的不断生成,其水合物颗粒会发生聚结,形成较大的水合物颗粒,随着反应的进一步进行,水合物颗粒粒径会表现为先增大后减小的趋势,这主要是由于水合物生成过程中的颗粒、液滴间的碰撞、聚集使得粒径增大,同时体系中增强的剪切作用和水合物颗粒表面润湿性的减小致使聚集的水合物颗粒又发生破碎所致;再则,实验过程中阻聚剂的加入对油水乳状液具有较好的乳化作用,使其水相较为均匀的分散到连续油相中,形成稳定、均一的乳状液体系,并且其分散相水滴的粒径要较不加剂情况下少;在水合物的形成过程中水合物颗粒间的聚并是导致水合物堵塞管道的主要原因。
