STUDY OF THE CORROSION INHIBITION MECHANISM OFRARE EARTH METAL(REM) ON B95 Al ALLOY WITH THESPILT CELL TECHNIQUE

摘要

A major complication in the study of corrosion inhibitors is the inability to separate the anodicand cathodic surface reactions. This inability makes it difficult to ascertain the effect of an inhibitor on theindividual corrosion processes. This complication is manifested in the absence of a definitive mechanismof action for common corrosion inhibitors and has contributed to the empirical nature of many corrosioninhibition studies. This paper puts forward a new method of studying the corrosion inhibition mechanismof rare earth metal(REM) on B95 Al alloy with the spilt cell technique. Firstly, the principle andexperimental method of the spilt cell technique are analyzed. Then by measuring the change ofnet-electric current between the two electrodes caused by the change of the amount of oxygen in thesolution and the addition of CeCl3, the authors of this paper did a research into the influence of corrosiveperformance of CeCl3 on B95 super-power aluminum alloy in the 0.1M NaCl solution. Meanwhile,another research was done into the conditional changes of pH values, CeCl3 solution and time ofperformance. Finally the authors revealed the features of electrode surface with the help of SEM andX-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques,such as potential-time curve, polarization curve and the like, the authors made a further approach intocerium(III) salt inhibition mechanism. The results are as follows:(1) The split cell technique presented serves as an effective method for the screening of corrosioninhibitor mechanisms. The method is a combination of galvanic corrosion and differential aeration cellswhich allows for partial separation of the anodic and cathodic reactions.(2) The rare earth Ce reduces the corrosive potential of B95 and restrains the corrosion of B95 Al alloyeffectively.(3) The spilt cell technique straightens out that Ce (III)has some restriction on B95 Al alloy cathodicreaction and CeCl3 proves to be an excellent coatings-forming aluminum alloy corrosion inhibitor.(4) The inhibition of Ce (III)on B95 Al alloy is closely related to pH values.(5) The conversion coating process falls in harmony with cathodic coating theory.