MODELING THE CORROSIVE EFFECTS OF VARIOUS MAGNESIUM ALLOYS EXPOSED TO TWO SALTWATER ENVIRONMENTS

摘要

The use of magnesium within the automotive industry is limited by its corrosion rate in the presence of saltwater. By adding various elements, the magnesium microstructure and corrosion rate can be altered. In the Center for Advanced Vehicular Systems at Mississippi State University, a model is being developed to elucidate the total corrosion of magnesium alloys and is comprised of general corrosion and pitting corrosion, respectively, as shown below:φ=φ_(gc)+φ_(IC)(1)where pitting corrosion is based on the pit number density, pit surface area, and a nearest neighbor distance function, respectively, as shown below:φ_(IC)=1_PV_PC(2)The exposure environment resulted in differences in the amount of pit nucleation, in the size of the pits formed, and in the rate of coalescence. Time also affected the surface characteristics, as general corrosion began degrade the number and size of the pits. The research presented here will cover the model development, calibration, and validation.