Surface corrosion poses a significant threat to the longevity and safety of aircraft. Given the extreme environments in which aircraft operate, ranging from high altitudes to coastal humidity, corrosion can lead to structural degradation, increased maintenance costs and even catastrophic failure if left unchecked. Understanding how to identify and mitigate surface corrosion is essential for ensuring aircraft reliability and safety.
Surface corrosion, also known as uniform corrosion, occurs when a metal is exposed to oxygen, moisture and environmental contaminants. Unlike localised corrosion forms like pitting, surface corrosion spreads evenly across a material’s surface, creating a dull, rough texture and often leading to the loss of material thickness over time. This type of corrosion primarily affects exposed metal surfaces, especially those that have lost their protective coatings due to wear, impact, or poor maintenance.
Surface corrosion is often overlooked in its early stages because it develops gradually and affects broad areas rather than isolated spots. However, early detection is crucial to prevent significant material loss.
The initial stage often presents as a slight discolouration, typically grey or chalky white in aluminium, or reddish-brown in steel. As the corrosion progresses, a visible powdery layer or slight pitting may form, signalling ongoing material loss. Over time, the affected areas may develop a rough, uneven feel, potentially compromising aerodynamics. Additionally, As corrosion progresses beneath the surface, it can lift and separate coatings, exposing more metal to deterioration.
Since surface corrosion is often widespread rather than localised, its prevention and management require a holistic approach that includes material protection, regular maintenance and environmental control.
Anodising and chromate coatings are electrochemical treatments that provide a resilient oxide layer that shields the underlying metal from oxidation. High-quality, corrosion-resistant paint with proper primers also offer an effective barrier against environmental exposure. Finally, treating surfaces with corrosion inhibitors prevents oxidation by forming a protective chemical layer on the metal.
Surface corrosion is usually manageable if caught early, making routine checks, especially in high-risk areas, essential. Frequent washing with approved aviation cleaners help remove salts, oils, and pollutants that accelerate corrosion. Small scratches, impact marks and abrasions should be addressed quickly with touch-up paint or protective sealants.
Light sanding or brushing with non-metallic pads can remove minor surface corrosion without damaging the base metal, Corrosion removal solutions (such as alkaline-based cleaners) dissolve oxidation before reapplying protective coatings. Once corrosion is removed, anodising, repainting or sealing the area prevents reoccurrence.
Surface corrosion is a persistent challenge that can silently compromise aircraft performance and safety over time. Unlike pitting or galvanic corrosion, which require aggressive localised interventions, surface corrosion demands an ongoing, proactive maintenance strategy.
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Our wire thread inserts provide superior joint durability, reducing wear in threaded components and helping to prevent structural failures caused by long-term material degradation. Download our guide below to learn more about the range of benefits that come with KATO write thread inserts.