Aerospace coatings are used on all aircraft to help protect the aircraft from corrosion. The livery coatings are changed regularly and are mostly decorative with their only functionality being the prevention of moisture penetration. Unlike livery coatings, the anticorrosive coatings on the Al2024 airframe must last the lifetime of the aircraft, which can be in excess of 40 years. During the aircraft’s lifetime, it will face extreme weather and temperature conditions (due to change of altitude during flight) as well as vastly different climates from coastal to hot desert to freezing snow. All of these factors will enhance the potential for corrosion of the copper rich aluminium alloy used in aircraft manufacturing. In addition, significant mechanical stresses are placed on the metallic structure during flying, take-off and landing, further increasing the risk of stress corrosion cracking and leading to catastrophic failure as in the Aloha Airlines Flight 243 in 1988, where 1 crew member was killed and 65 passengers injured. Current testing for aerospace primers for US military aircraft have to pass 2000 hours of salt spray testing while other tests call for in excess of 3000 hours and even up to as high as 9000 hours in salt spray testing. In aerospace application the aluminium alloy that is primarily used in Al2024 which is a lightweight alloy that utilises mainly copper to impart greater strength. The grain boundary between the copper and aluminium is a prime spot for corrosion to take hold giving rise to crevice corrosion or stress corrosion cracking. For this reason aerospace coatings utilise anti-corrosive primers to help prevent corrosion on the airframe.
Ceramisphere has been working in the area of aerospace coatings for over a decade. We have developed unique chromate free solutions that can be used in aircraft primer coatings as a substitute for toxic chromates. The unique Inhibispheres® products that have been developed to protect Al2024 include Inhibispheres® M and Inhibispheres® B. These products utilise novel organic corrosion inhibitors and have none of the toxic labelling concerns associated with the use of chromates. The organic inhibitors inside the Inhibispheres® are compatible with all types of aerospace coatings whether traditional solvent base coatings or with newer more environmentally benign coating like high solids and water based or water reducible systems that look to meet increasing VOC requirements worldwide. Inhibispheres products are compatible with each other as well as third party tradition corrosion inhibitors. They can be used alone or with others to enhance and extend corrosion protection on metal substrates that are susceptible to attack by corrosion initiators. Inhibispheres products have been extensively tested in salt spray testing and electrochemical testing and can be seen to provide corrosion protection on Al2024. Inhibispheres have been shown to be particular useful in low oxygen environments that give rise to crevice corrosion. When joint sealing is less effect than it should be Inhibispheres can help to make the difference to prevent corrosion in these environments.
Inhibispheres® from Ceramisphere offer a step change in the corrosion protection solutions for coating formulators in the aerospace coating industry.
Automotive coatings is an area where coatings are used extensively. Demand for vehicles worldwide is increasing as more countries become wealthier and the expanding middle class in developing countries has aspirations of automobile ownership. Asia is certainly the largest growing market and where significant growth can be seen. Automotive production in East Asia (China, Japan, Korea) is growing year on year. Corrosion control in coatings is essential for the lifetime of the automobile. Rusting on the vehicle body must be prevented for the vehicle to maintain its structural integrity. The visual aesthetic for the coating on the vehicle body must be consistent and not interfere with the gloss properties of the coating.
Inhibispheres® can be used to prevent corrosion on steel and aluminium auto body frames. Inhibispheres® M is good at preventing corrosion on both substrates. These corrosion inhibitors can be used in primers and topcoats or basecoat clearcoat or even in e-coat. The unique mechanism of inhibitor release allows for corrosion protection over the entire life time of the vehicle utilising efficient organic and organometallic corrosion inhibitors. Due to Inhibispheres® size they can also be used in topcoats and clear coats without affecting the coating’s optical properties. The gloss can be maintained while also adding anti-corrosive functionality.
Paints for the inside of freight rail cars have variable requirements depending on the nature of the material being transported (food, petrochemicals, crops, corrosive liquids). Whether they be hoppers, boxcars, tankers or the engines themselves corrosion is a key issue. The external component of the rail cars as well as the engines require anticorrosive protection from the environment. The cars are usually roughly treated in the demanding work environment of the railroad.
The crude oil tanks often contain significant amounts of water which can cause corrosion inside tanks. This in turn can cause problems for the crude oil quality as the corrosion give rise to contamination of the crude itself. Without proper protection but both the carriage and the freight can be devalued.
Inhibispheres® can be used to help stem the corrosion in rail applications on engines, containers, boxcars, wagons, hoppers and tankers. Inhibispheres® A, Inhibispheres® M, Inhibispheres® ZB and Inhibispheres® ZS can all be used to protect steel from corrosion when they are incorporated into protective coatings.