Nanotechnology-Based Self-Healing Coating System to Enable Extensive Use of Magnesium Alloys in Automotives

The fuel efficiency of automobiles can be enhanced by using lightweight materials such as magnesium alloys. However, unlike steel, magnesium alloys corrode rapidly. Although magnesium alloys can be protected against corrosion by chromate-based coatings, chromates are being phased out due to toxicity and environmental concerns. Therefore, there is an immediate need to develop non-chromate corrosion-resistant coatings with ¿self-healing¿ characteristics, similar to those of chromate-based coatings. This project will demonstrate the feasibility of producing coating formulations containing nanoscale corrosion inhibitors, such that the coating exhibits self-healing behavior. In Phase I, coatings will be applied on two different magnesium alloys, and the corrosion protection performance of coatings will be evaluated by electrochemical techniques (e.g., AC Impedance Spectroscopy and DC Polarization) and salt spray. Once the proof-of-concept is demonstrated, prototype automotive components will be coated and tested in Phase II. Commercial Applications and other Benefits as described by the awardee: The chromate-free coating technology should lead to an increase in the use of magnesium alloys in automobiles. Various automotive components, such as chassis, powertrain, and doorframe can be made from magnesium alloys. Improvement in the fuel efficiency of automobiles associated with the increased use of lightweight magnesium alloys should help to reduce the emission of greenhouse gases.