Aircraft corrosion is a significant challenge in the aerospace industry, impacting aircraft safety, performance and maintenance costs. Corrosion occurs when metals deteriorate due to environmental exposure, leading to weakened structural integrity and potential failures. Understanding the causes and implementing effective engineering solutions is crucial for maintaining aircraft longevity and operational efficiency.
As aircraft operate in diverse and often harsh environments, there is a constant battle against corrosion to protect vital components from deterioration and maximise their lifespan. The materials used in aircraft structures, particularly aluminium and titanium alloys, are chosen for their strength-to-weight ratio. However, these materials can still corrode under certain conditions and be susceptible to specific forms of corrosion.
Galvanic corrosion - Occurs when two dissimilar metals come into contact in the presence of an electrolyte, such as moisture. This is common in dissimilar metal assemblies.
Pitting corrosion - A localised form of corrosion that creates small holes or pits in metal surfaces, often caused by salt exposure.
Crevice corrosion - Develops in confined spaces where moisture is trapped, such as under fasteners or between overlapping metal surfaces.
Intergranular corrosion - Results from grain boundary deterioration in metal alloys, reducing material strength and integrity.
Fretting corrosion - Occurs due to repeated contact and movement between two metal surfaces, leading to wear and oxidation.
Aircraft are constantly exposed to varying atmospheric conditions. High humidity, salt-laden air (particularly in coastal and marine environments) and pollutants can accelerate corrosion.
Extreme temperature changes cause metals to expand and contract, leading to microcracks that can become initiation points for corrosion.
Water can accumulate in areas with poor drainage, such as landing gear wells, fastener recesses and structural voids, creating an ideal environment for corrosion.
Failure to regularly clean, inspect and treat aircraft surfaces can lead to undetected corrosion. Corrosive residues left from de-icing fluids, bird droppings or industrial pollutants can reinforce the problem.
To mitigate corrosion risks, engineers employ a range of solutions that enhance aircraft durability and longevity.
Applying anti-corrosion coatings such as anodising, chromate conversion coatings, or specialised paint systems helps create a protective barrier against environmental factors. These coatings enhance corrosion resistance while maintaining the lightweight properties of aircraft materials.
Using corrosion-resistant materials, such as titanium alloys, composite materials and stainless steel, can significantly reduce corrosion risks. Advances in material science have led to the development of high-strength, lightweight alloys that provide better resistance to environmental degradation.
Scheduled inspections using non-destructive testing (NDT) methods, such as ultrasonic testing, help detect early-stage corrosion before it compromises structural integrity. Routine cleaning and application of corrosion inhibitors also extend the lifespan of aircraft components.
Wire thread inserts provide an advanced solution for protecting fastener joints and preventing corrosion-related failures. These inserts are designed to enhance joint integrity by distributing stress evenly and isolating fasteners from direct contact with corrosive elements.
Prevention of galvanic corrosion: Wire thread inserts act as a barrier between dissimilar metals, reducing the risk of galvanic reactions.
Enhanced fastener strength: By distributing load more effectively, these inserts prevent thread stripping and wear that can lead to fretting corrosion from surface wear and oxidation.
Material and coating options: Wire thread inserts can act as a protective layer against corrosion as they are available in resistant materials such as phosphor bronze and stainless steel, with additional coatings like cadmium plating for enhanced protection.
Aircraft corrosion remains a critical challenge that requires proactive engineering solutions. By understanding the causes and implementing protective measures such as advanced coatings, optimised materials, rigorous maintenance programmes, and innovative fastening solutions like wire thread inserts, the aerospace industry can significantly extend the operational lifespan of aircraft.
With ongoing advancements in corrosion-resistant technologies like wire thread inserts, aircraft manufacturers and maintenance teams can ensure that aircraft remain safe, efficient and reliable throughout their service life. To find out more about how wire thread inserts can protect aircraft mechanical joints from failure, read our comprehensive guide below.