Corrosion Resistance in Flight — How Fasteners Endure the Elements
The Constant Enemy: Corrosion
Every aircraft — whether it’s a passenger jet, fighter, or satellite support vehicle — faces an invisible, relentless adversary: corrosion. From salt spray at low altitude to condensation during pressurization cycles, the environment constantly attacks metal surfaces.
For aerospace fasteners, corrosion isn’t just a cosmetic issue. It’s a structural and safety threat that can weaken joints, reduce torque integrity, and accelerate fatigue failure. That’s why aerospace fasteners are designed not just for strength, but for endurance — resisting the elements through careful material selection, coatings, and design practices.
Why Aerospace Corrosion Is Different
Aircraft experience conditions that are vastly harsher than ground-based equipment. Corrosion occurs through multiple mechanisms, each worsened by flight dynamics and environmental exposure:
Altitude cycling: Rapid changes in pressure and temperature cause condensation and oxidation.
Salt and humidity exposure: Constant concern for naval or coastal aircraft.
Chemical and fuel contact: Hydraulic fluids, jet fuel, and de-icing agents accelerate corrosion.
Stress corrosion cracking: When mechanical load and corrosive exposure combine to produce microscopic fractures.
These factors demand a specialized approach. Aerospace fasteners must perform flawlessly through thousands of flight hours — often under the same conditions that steadily degrade surrounding structures.
Material Selection for Corrosion Resistance
Corrosion resistance begins with metallurgy. Aerospace-grade fasteners are engineered from materials that maintain mechanical integrity and chemical stability in extreme conditions:
Titanium alloys (Ti-6Al-4V): Exceptional corrosion resistance across saline and acidic environments, while providing excellent strength-to-weight ratio.
Nickel-based superalloys (Inconel, A286): Maintain high strength and oxidation resistance in turbine and exhaust assemblies.
Stainless steels (AISI 316 and PH grades): Ideal for interior and secondary applications where corrosion protection and durability are equally important.
Aluminum fasteners: Lightweight and corrosion-resistant when anodized, though limited to non-structural assemblies due to galvanic potential.
Selecting the right alloy ensures longevity — often reducing the need for heavy surface treatments while maintaining reliable torque and preload over years of operation.
Surface Treatments & Coatings
Even the strongest alloys need protection. Aerospace coatings act as barriers against moisture, oxidation, and galvanic interaction between dissimilar metals.
Common finishes include:
Cadmium plating: Historically the aerospace standard for corrosion and lubricity, now restricted under environmental regulations.
Zinc-nickel plating: A leading cadmium alternative offering comparable corrosion resistance and conductivity.
Silver plating: Used for high-temperature fasteners, providing anti-galling and conductivity in turbine assemblies.
Dry film lubricants (DFL): Reduce friction during torqueing and minimize galling without affecting mechanical properties.
Anodizing and passivation: Enhance oxide layers on stainless or aluminum hardware, improving surface stability.
The goal is balance — coatings must protect without interfering with preload, elasticity, or thread geometry. In aerospace, even microns of thickness variation can affect torque-tension relationships.
Design & Installation Considerations
Preventing corrosion extends beyond material and coating choice — it’s about how fasteners are used and installed.
Isolation washers and sealants: Reduce galvanic potential between metals with different electrochemical properties.
Controlled torque application: Prevents cracking or over-compression of coatings.
Proper drainage and joint design: Avoid moisture entrapment that leads to crevice corrosion.
Corrosion prevention is designed in, not added later. Once oxidation begins inside a joint, the cost and complexity of repair rise sharply — especially in inaccessible flight structures.
Regulatory & Environmental Shifts
The aerospace industry is undergoing a major transition away from legacy coatings toward environmentally responsible solutions.
REACH restricts cadmium and hexavalent chromium due to toxicity concerns.
RoHS compliance affects export and OEM procurement standards globally.
Next-generation coatings — including zinc-nickel, tin-zinc, and trivalent chromium — now match or exceed cadmium’s protection.
Innovations like plasma vapor deposition (PVD) and nano-ceramic coatings are also emerging as durable, lightweight alternatives. At California Fastener, we work with aerospace and defense clients navigating this shift — offering compliant, specification-approved finishes without compromising performance or reliability.
Inspection, Maintenance & Lifecycle Control
Corrosion prevention is a continuous process. Aerospace maintenance programs include:
Routine inspections to detect pitting, discoloration, or oxidation.
Torque checks to identify preload loss caused by corrosion or galling.
Scheduled fastener replacement cycles based on exposure hours and environmental conditions.
Each part is fully traceable — every coating, material batch, and inspection record can be verified through certification documentation. That level of transparency keeps aircraft compliant and safe throughout their service life.
California Fastener’s Role in Corrosion-Resistant Aerospace Supply
California Fastener supports aerospace and defense programs with spec-compliant, corrosion-resistant fasteners across NAS, MS, AN, and AS standards.
Our inventory includes:
Titanium, Inconel, A286, and PH stainless alloys
Zinc-nickel and silver-plated hardware
Cadmium-free alternatives for REACH and RoHS compliance
Pre-kitted assemblies to simplify maintenance and inspection workflows
We combine documentation accuracy, traceability, and material expertise to ensure every fastener performs — from initial flight testing to long-term maintenance.
FAQs
Q: Why is cadmium being phased out in aerospace?
A: Environmental and worker safety regulations like REACH and RoHS now restrict cadmium use. Zinc-nickel and trivalent chromium finishes provide safer, high-performance alternatives.
Q: Is stainless steel corrosion-proof?
A: No. While highly resistant, stainless can still suffer pitting and stress corrosion under chlorides or acidic exposure.
Q: What’s the best coating for high-temperature fasteners?
A: Silver plating or dry film lubricants — they maintain torque consistency and prevent galling under heat.
Q: How long do aerospace coatings last?
A: Typically through one full maintenance cycle, depending on environmental exposure and inspection intervals.
Built to Endure at 30,000 Feet
In aerospace, corrosion resistance isn’t optional — it’s a cornerstone of safety and reliability.
Fasteners endure the harshest conditions in flight, quietly ensuring that every joint, assembly, and component performs as designed.
At California Fastener, we supply corrosion-resistant, spec-compliant hardware that stands up to altitude, temperature, and time — because in aerospace, endurance is everything.
Contact us to source certified aerospace fasteners designed to meet NAS, MS, AN, and AS standards.
