Here’s juicy news for the protective coatings industry: The newest potential secret weapon in the war on corrosion comes from the date palm, cultivated for its edible sweetfruit.
Yes, the search for a “greener” way to prevent corrosion on the kind of aluminum used in jetliners, cars and other products has led scientists to the juice of the date palm — those tall, majestic trees that have long been prized as sources of food and traditional medicines.
“Anti-Corrosive Properties of Date Palm (Phoenix dactylifera L.) Fruit Juice on 7075 Type Aluminium Alloy in 3.5% NaCl Solution,” newly published in the American Chemical Society’s Industrial & Engineering Chemistry Research, tells how.
Husnu Gerengi’s research involves the strong, lightweight aluminum alloys used to make planes, cars and industrial equipment.
Aluminum corrodes when exposed to air, but unlike rusting steel, the corrosion of aluminum’s surface layer forms a protective film that prevents degradation of the underlying metal. However, that film breaks down in some harsh environments, like seawater, leaving the metal vulnerable. Engineers have developed coatings to protect aluminum in these applications, but many of these use potentially toxic chemicals.
Previous research suggested that extracts of date palm leaves had an anti-corrosion effect. Gerengi decided to give date palm juice a try.
Gerenji found that date palm juice inhibited corrosion of an aluminum alloy called AA7075, used in aerospace and other applications, in a salt solution. Gerengi noted that while an extract from date palm leaves is a known anticorrosive, this was the first test of the fruit’s juice.
The juice, which absorbed into the aluminum’s surface, contains a number of sugars. Gerengi posited that these react with aluminum to form an anticorrosive film on the metal’s surface.
The author acknowledges funding from the Scientific and Technological Research Council of Turkey.