Study On In-door Accelerated Tests Of Atmospheric Corrosion Of Aluminum Alloy

ABSTRACT In this thesis, for four kinds of aluminum alloys, LC4 aluminumalloy with Al and without Al clad, LY12 aluminum alloy with Al clad andwithout clad which were widely used in aeronautic industry, the in-dooraccelerated tests including continuous salt spray, cyclic salt spray andcyclic immersion test were carried out. The corrosion current-time curveswere measured by means of atmospheric corrosion monitor (ACM),which can provides evidence for evaluating the simulation of acceleratedtest. For the three tests above, the corrosion kinetic analysis, morphologyand composition of the corrosion product and protective character ofcorrosion layer was investigated. The protective property of corrosionproduct layer was studied by polarization curves measurement. Theresults of A.C impedance measurement revealed that the transfer ofcorrosive medium is controlled by diffusion process, so the corrosionproduct layer has good protection to the matrix. According to the weight loss data from Wanning out-door exposuresite, the simulation and acceleration of different accelerated tests wereanalyzed and the concluded correlation was given. As for LC4 and LY12 aluminum alloy with Al clad, the cyclicimmersion test has better correlation with out-door exposure test atWanning exposure site than continuous salt spray; As for LC4 and LY12aluminum alloy without Al clad, the correlation with the out-doorexposure test at Wanning should be in the sequence below: cyclic saltspray test, cyclic immersion test and continuous salt spray.