Materials Selection for Gasoline/Methanol Blend Fuel Systems 930447
The Clean Air Act of 1990 stipulated tougher industry-wide standards for environmental pollution control from mobile sources. One way the U.S. automobile manufacturers may achieve compliance with the more stringent federal standards is to produce cars which utilize cleaner burning methanol blend fuels. However, the major shortcoming of the methanol blend powered vehicle is the accelerated corrosion of metallic components in direct contact with the fuel.
Consequently, a laboratory test program was developed to screen suitable materials for the corrosive fuel environment. The metals selected for this test series were based on corrosion data from the National Association of Corrosion Engineers (NACE). They include stainless steel 304, 1010 steel and 356 aluminum. Established protective coatings and surface treatments, namely, electroless nickel, DACROMETB and conventional anodizing were also included in the test series.
Guidelines issued by the SAE Cooperative Research Program 1990 were followed during testing. Laboratory methodology conformed to ASTM G31, “Standard Practice for Laboratory Immersion Corrosion Testing of Metals”.
Based on specimen appearance and corrosion rates, the CM85A and CM85AP fuels were the most aggressive fuels out of the six tested at the conclusion of 2,000 hours test time. Overall, electroless nickel coating on steel and on aluminum and anodized aluminum, demonstrated the best corrosion performance under the controlled test conditions.