Development of a corrosion protection system for aluminum alloys and evaluation of system's effectiveness

Abstract

Even with advances in the prevention of corrosion the cost of corrosion to the US economy is over a $1 trillion in today's dollars. Research into new more effective corrosion control methods is imperative. Of the different types of corrosion, galvanic corrosion is the most common and the most destructive. This research investigates the superhydrophobic coating to provide mitigation of the galvanic corrosion mechanism in aluminum alloys. A superhydrophobic coating was developed by creating a micro-nanostructure hierarchical morphology using micosized and nano- sized metallic particles with a silicone component. Then the coating was shown to have an average water contact angle (WCA) of 158° with a high of 163° , an average sliding angle of 4.05° with a 7.6° hysteresis. Durability of the coating was tested with acetone, and an acid solution which had no effect on WCA and but a base lowered the WCA considerably. The corrosion mitigation of the coating was determined by comparing electrochemical testing of coated specimens and with testing of the bare aluminum materials. The coating was effective in significantly lowering the corrosion rates of the coated specimens compared to the bare aluminum as shown in Figure 1(a). The corrosion current shifted significantly more anodic as seen in Figure 1(b). The corrosion properties for the coated aluminum as well as the weld material were significantly improved over the bare material.