The Corrosion Behavior of Metals, Plated Metals, and Metal Coatings in Methanol/Gasoline Fuel Mixtures

Government clean air regulations have prompted much interest in the automotive industry in alternative fuels for lower emission vehicles. Methanol fuels have become the primary focus of the auto companies in meeting these challenges. Even though the corrosiveness of methanol and commercial methanol fuel blends is well recognized, no systematic investigations on the relative corrosion behavior of metals and their coatings in these solutions are available.

The purpose of the present study is to determine the relative corrosion rates for metals, plated metals, and otherwise coated metals that were exposed to ionic and water contaminated methanol/gasoline fuel mixtures. The results are described for samples that were immersed in M15 and M85 test fuels for between 2000 to 8000 hours under static laboratory conditions at 40°C. The primary measure of corrosion was mass loss, which was used to generate corrosion rates, where possible, for each of the specimens. The test results show that a high percentage of the materials tested display some measure of degradation in alcohol fuel blends. However, some metals and organics were shown to be viable barrier coatings for the protection of steel and aluminum in these fuels.