Common Causes of Fastener Corrosion (and How to Prevent Them)
Fastener corrosion is one of the leading causes of premature joint failure across industries. Even high-strength fasteners can fail when exposed to unfavorable environments or improper material and coating selection.
This guide explains the most common causes of fastener corrosion and provides practical prevention strategies engineers and buyers can apply in real-world applications. Part of our comprehensive guide on corrosion resistant fasteners.
Why Fastener Corrosion Matters
Corrosion does more than affect appearance. It can lead to:
- •Loss of mechanical strength
- •Seized or stripped threads
- •Loosening of joints
- •Increased maintenance and replacement costs
- •Safety and reliability risks
Understanding why fasteners corrode is the first step toward preventing failure.
1. Moisture and Humidity Exposure
The Cause
Water acts as an electrolyte, enabling electrochemical reactions that lead to rust and oxidation—especially on carbon and alloy steel fasteners.
High-risk environments include:
- •Outdoor installations
- •Coastal regions
- •High-humidity industrial facilities
How to Prevent It
- •Use corrosion resistant fasteners
- •Apply protective coatings such as nickel or zinc-nickel
- •Ensure proper drainage and ventilation in assemblies
2. Salt Spray and De-Icing Chemicals
The Cause
Chloride ions from salt accelerate corrosion dramatically and can penetrate many standard coatings.
Common exposure sources:
- •Road salt
- •Marine environments
- •Coastal air
How to Prevent It
- •Specify zinc-nickel coated fasteners for extended salt spray resistance
- •Avoid uncoated carbon steel in salt-exposed applications
- •Design assemblies to minimize salt accumulation
3. Galvanic Corrosion (Dissimilar Metals)
The Cause
When two different metals are in electrical contact in the presence of moisture, the less noble metal corrodes faster.
Typical examples:
- •Steel fasteners with aluminum components
- •Mixed stainless steel and carbon steel assemblies
How to Prevent It
- •Match fastener material to the base material when possible
- •Use barrier coatings such as nickel plating
- •Add insulating washers or sealants
4. Chemical Exposure
The Cause
Fasteners exposed to chemicals such as:
- •Oils
- •Cleaning agents
- •Acids or alkalis
may experience accelerated corrosion or coating breakdown.
How to Prevent It
- •Select coatings with chemical stability (e.g., electroless nickel)
- •Verify chemical compatibility during material selection
- •Avoid coatings known to degrade in specific chemical environments
5. Temperature Cycling and Heat Exposure
The Cause
Repeated heating and cooling can:
- •Break down protective coatings
- •Accelerate oxidation
- •Reduce coating adhesion
This is common in:
- •Engine compartments
- •Power electronics
- •EV battery systems
How to Prevent It
- •Use heat-resistant coatings such as zinc-nickel
- •Avoid standard zinc coatings in high-temperature zones
- •Validate coatings under thermal cycling conditions
6. Mechanical Damage to Coatings
The Cause
Scratches, impact, or over-torqueing can damage coatings, exposing the base metal and creating corrosion initiation points.
How to Prevent It
- •Use coatings with strong adhesion and wear resistance
- •Specify appropriate installation torque
- •Consider electroless nickel for applications involving repeated assembly
7. Improper Coating Selection
The Cause
A coating that performs well in one environment may fail in another.
Common mistakes include:
- •Using zinc in severe salt environments
- •Using decorative nickel where wear resistance is required
- •Ignoring lifecycle requirements
How to Prevent It
- •Match coating type to environmental and mechanical demands
- •Use comparison guides such as nickel vs zinc vs zinc-nickel coatings
- •Consider total lifecycle cost, not just initial price
Materials vs Coatings: A Shared Responsibility
Fastener corrosion resistance depends on both:
- •Base material (carbon steel, alloy steel, stainless steel)
- •Surface coating (zinc, nickel, zinc-nickel, etc.)
In many applications, a coated high-strength steel fastener offers the best balance of strength and corrosion protection.
See our overview of corrosion resistant fasteners for a complete material and coating breakdown.
Final Thoughts
Fastener corrosion is rarely caused by a single factor. It is usually the result of environmental exposure, material selection, and surface treatment working together—or against each other.
By understanding the common causes of corrosion and applying the right prevention strategies, engineers and buyers can significantly extend fastener life, improve reliability, and reduce long-term costs.
Related Guides
Corrosion Resistant Fasteners Guide
Complete guide to materials, coatings, and applications.
How Nickel Coatings Protect Fasteners
Learn about barrier protection, wear resistance, and chemical stability mechanisms.
Nickel vs Zinc vs Zinc-Nickel Coatings
Compare protection mechanisms, performance, and cost across coating types.
Coating Technology
Advanced surface treatment processes and capabilities.
Need Help Preventing Fastener Corrosion?
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