Why aerospace parts are often green ✈️🟢
Green aerospace parts stand out immediately. But the colour is not aesthetic and not coincidental.
In aerospace manufacturing, green coatings are the result of decades of engineering practice, driven by corrosion protection, inspection needs and operational reliability.
Below, we explain the main reasons why green coatings are still widely used in aerospace today.
Zinc chromate as the origin of the green colour
The characteristic green colour originates from zinc chromate, a pigment that naturally has a yellow to green-yellow appearance. When zinc chromate is used in a primer, that colour remains visible on the part.
Zinc chromate primers have been used in aerospace since the 1930s and quickly became common across both civil and military aircraft programs.
Corrosion protection for critical materials
Aircraft components are often made from aluminium and magnesium alloys, which are lightweight but sensitive to corrosion.
Zinc chromate primers provide excellent corrosion protection by reacting with the metal surface and forming a passivating layer. This layer protects the material against moisture and oxidation. In addition, chromate-based systems can partially re-form a protective film when small scratches occur, helping to protect exposed areas.
This corrosion resistance is one of the main reasons why green primers became standard in aerospace applications.
Improved visibility during production and inspection
The green colour also has a practical advantage during manufacturing, inspection and maintenance.
Green coatings are highly visible in low-light or enclosed areas, such as inside wings or structural cavities. The uniform colour makes it easier to detect damage, contamination, wear or early signs of corrosion. For inspectors and technicians, this improves reliability and efficiency during visual checks.
A long-standing aerospace standard
Over time, green primers became a de facto standard in aviation. Both civil and military programs adopted them widely, which led to strong familiarity across the industry.
Even as new coating technologies emerged, the green appearance remained associated with aerospace-grade protection and quality.
Green coatings in modern aerospace programs
Today, environmental regulations increasingly drive the use of chromate-free primers. However, many of these modern alternatives are still produced in a green shade.
The reason is simple. Technicians are accustomed to the colour, and the visibility benefits for inspection remain valuable. While the chemistry evolves, the practical advantages of green coatings continue to apply.
Engineering logic behind a simple colour
What may look like a simple paint choice is in fact the result of decades of operational experience. Green aerospace coatings combine protection, visibility and standardisation, all essential in safety-critical manufacturing.
At BMT Aerospace, surface treatments are selected based on function, reliability and compliance, ensuring that every component is prepared for its role in demanding aerospace environments.