Evaluation of the technique 'wire on the screw' in laboratory accelerated essays

The CLIMAT essay has been employed as for the micro climate corrosiveness determination as for large geographic zones, allowing the qualification of corrosiveness of the interesting sites, the maps raising, the materials evaluation and the pollution focus localization. However, its utility, this has not been deepen in the understanding of his characteristics and corrosive process that it experiments. With the purpose in order to deepen in its knowledge and evaluating the useful possibilities in an immersion-emersion accelerated essay, it was accomplishment the present work. For this, was employed spiral aluminium manometers forming a galvanized pair with copper and steel screws, which were exposed to representative dissolutions of rainwater of the rural, urban and marine environment. It was measured the electrode potential for the essays, the corrosion velocities were determined gravimetrically, it was drawing polarization curves and they were characterized the corrosion products by X-ray diffraction (XRD), Infrared spectrometry (Ftir), Scanning Electron Microscopy (Sem) and stereoscopic microscope. The results allow to conclude that must pass sometime for what galvanic action was established. The potential evolution after that initial time, is approximately the same for the two pairs, for which the main losing of mass obtained in the Al-Cu screw has to be explained with kinetic arguments offered for polarization curves. The main corrosion product is bayerite (Al(OH)3), with greater crystallinity in Cl- dissolution than in SO4(2-) and with morphologies very influenced by environment. (Author)