Topic of the Month: Solution of Aircraft Wing Exhaust Gas Corrosion Problem Is Nearer

Among its many corrosion problems, the aircraft industry is concerned particularly with the behavior of impinging exhaust gases upon the wings and fuselage of the plane. These gases, somewhat similar in composition to automobile exhaust gases, carry with them a volatile lead compound originating in the anti-knock ingredient, lead tetraethyl. Normally, to each gallon of aviation gasoline there is added from 3 to 4.5 milliliters of a liquid whose composition approximates 1.7 parts of lead tetraethyl to one part of ethylene dibromide. The latter material behaves as a scavenger compound preventing internal lead deposition by forming the relatively low melting (370 C) and volatile compound—lead bromide (bp 916 C). It is this compound that has been identified as comprising as high as 90 percent of the deposit found on the plane’s wing. This substance, along with moisture, initiates a series of reactions believed responsible for a very serious corrosion problem....