When it comes to aerospace engineering, the design of a component is only part of the story. Equally critical is the finish or coating applied after manufacturing. The right finish can dramatically extend the life of a component, improve its resistance to harsh environments, and even contribute to aesthetics. In aerospace, where components are exposed to intense heat, vibration, and atmospheric extremes, finishes are not just decorative — they are essential for safety, efficiency, and performance.
This article explores the main types of finishes and coatings used in aerospace applications, their benefits, and the factors engineers must consider when choosing the right one.
Why Finishes Matter in Aerospace
Aerospace parts face some of the harshest working conditions of any industry. They must withstand:
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Temperature Extremes – Engines and exterior parts endure blistering heat and freezing cold.
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Mechanical Stresses – Vibration, pressure fluctuations, and constant movement put enormous strain on materials.
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Corrosive Environments – Moisture, chemicals, and atmospheric oxygen accelerate material degradation.
A bare, untreated surface is vulnerable to wear, corrosion, and structural weakening. Finishes and coatings act as protective barriers and, in many cases, enhance performance by reducing friction, controlling corrosion, or improving wear resistance.
Manufacturing Processes and Finishing Opportunities
The type of finish often depends on the manufacturing method used to produce the component. Here are some common aerospace processes and how finishing fits into each:
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CNC Machining – Produces highly precise parts with fine surfaces. Finishes such as anodizing, electroplating, or electropolishing are often applied to protect and enhance surface quality.
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Sheet Metal Fabrication – Provides durable flat or bent parts. These surfaces often require coatings such as powder coating or chromate conversion to prevent corrosion and maintain integrity.
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3D Printing (Additive Manufacturing) – Creates complex geometries in metals, plastics, or elastomers. Finishes such as vapor smoothing, dyeing, or ceramic coatings improve both aesthetics and functionality.
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Injection Molding – Ideal for plastics and elastomers in higher volumes. Finishes can include dyeing, texturing, or flame-resistant coatings depending on the application.
The finishing choice should be integrated into the design and manufacturing plan from the beginning, not added as an afterthought.
Types of Finishes and Coatings for Aerospace
1. Metal Finishes
Electropolishing
This process removes a microscopic layer from the surface, smoothing rough areas and producing a shiny, uniform finish. It’s ideal for complex geometries since it coats internal surfaces evenly. In aerospace, electropolishing reduces friction, improves fatigue resistance, and enhances cleanliness.
Media Blasting
Using fine abrasive particles, media blasting produces a uniform, textured surface that hides machining marks and prepares parts for subsequent coatings. This method is often used before applying paints, powder coatings, or platings.
Brushed or Polished Finishes
These finishes improve surface consistency and appearance. While they are primarily aesthetic, they also remove surface imperfections that might otherwise compromise fatigue resistance.
2. Plastic Finishes
Vapor Smoothing
Used mainly with 3D-printed plastics, vapor smoothing melts uneven surface layers using vaporized chemicals. This process seals pores, improves water resistance, and enhances surface aesthetics. It also makes components easier to clean — a critical benefit for aerospace interiors.
Dyeing and Coloring
Additive manufacturing processes like Multi Jet Fusion (MJF) produce parts that can be dyed in rich, uniform colors. This is particularly useful for interior cabin components where appearance and branding matter alongside performance.
3. Advanced Coatings
Cerakote
A ceramic-based coating known for strength and resistance to abrasion, Cerakote is thin, lightweight, and available in dozens of colors. It protects against corrosion, chemicals, UV light, and extreme temperatures, making it an excellent choice for aerospace environments.
Powder Coating
Electrostatically applied powder pigments are baked onto parts, forming durable, thick coatings. While excellent for sheet metal parts, powder coating can add extra weight — an important consideration in aerospace where every gram counts.
Plating
Electroplating and electroless plating add a layer of metal to protect against corrosion and wear. They also reduce friction between moving parts, which improves efficiency and prolongs service life.
Best Finishes for Harsh Aerospace Environments
Cerakote
Few finishes rival Cerakote’s performance. Its thin but rugged ceramic coating is compliant with RoHS and REACH standards, making it safe and environmentally responsible. It withstands vibrations, extreme temperatures, chemical exposure, and UV radiation. In aerospace applications, Cerakote is valued for combining strength with minimal weight, which is crucial when fuel efficiency and payload capacity are at stake.
Electroplating
Electroplating adds a sacrificial metallic layer that protects the underlying material. When exposed to corrosion, the plated layer deteriorates instead of the base material. This makes electroplating an excellent choice for moving parts where reduced friction, wear resistance, and fatigue prevention are essential.
Best Choices for Corrosion Resistance
Corrosion is one of the most dangerous threats to aerospace components. Preventing it is critical for safety and longevity. Several finishes provide strong protection:
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Passivation – Applied to steels, passivation creates a stable oxide layer that resists rust. It neutralizes reactive iron surfaces, preventing oxidation from spreading deeper.
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Chromate Conversion Coating – Common for aluminum, this process produces a thin chromium oxide layer that resists corrosion while serving as a primer for additional coatings such as paint.
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Anodizing – By running an electric current through aluminum in an acid bath, anodizing creates a durable oxide layer. This controlled corrosion forms a protective surface that resists wear while remaining porous enough to accept dyes. Anodizing provides corrosion protection and can also give parts a vibrant, metallic aesthetic.
Applications Across Aerospace
Different aerospace components demand different finishing solutions:
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Engines and High-Temperature Parts – Require coatings like Cerakote or electroplating to withstand heat and reduce wear.
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Aircraft Interiors – Finishes such as vapor smoothing and flame-resistant coatings ensure durability and safety.
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Exterior Surfaces – Anodizing and chromate conversion coatings protect against corrosion while minimizing added weight.
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Precision Moving Parts – Electropolishing and plating reduce friction and mechanical fatigue.
Each aerospace application must balance weight, performance, durability, and compliance with regulatory standards. The right finish often determines whether a part meets its full lifecycle expectations.
Design Considerations for Finishing
To maximize the benefits of finishes and coatings, engineers should consider design factors early in the process:
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Uniform Wall Thickness – Ensures consistent finishing results, particularly for processes like vapor smoothing.
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Surface Preparation – Polishing or blasting surfaces before coating can improve adhesion and final quality.
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Weight Impact – While some finishes are extremely thin, others (like powder coatings) add significant weight that may be undesirable.
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Aesthetics vs. Functionality – Aerospace components must balance performance with appearance, particularly in passenger-facing parts.
By integrating these considerations into the design stage, manufacturers can ensure that coatings and finishes contribute effectively to performance and longevity.
Conclusion: Finishing as a Critical Factor in Aerospace Manufacturing
In aerospace, every detail matters. Finishes and coatings are more than cosmetic; they provide essential protection against corrosion, wear, and extreme environments. Choosing the right finish can extend part life, reduce maintenance costs, and improve safety.
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For high-heat and high-wear applications: Cerakote and electroplating are top choices.
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For corrosion resistance: Passivation, chromate conversion, and anodizing are highly effective.
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For aesthetics and durability in plastics: Vapor smoothing and dyeing are excellent options.
By combining thoughtful design with the right finish, aerospace engineers can create components that not only meet but exceed performance requirements.
At Protolabs, we offer comprehensive manufacturing services — from CNC machining and sheet metal fabrication to 3D printing and injection molding — supported by an extensive library of finishing options. Our experts work closely with engineers to ensure every aerospace component is optimized for its environment, performance requirements, and longevity.
