Corrosion Protection Coatings
Corrosion protection coatings extend the service life of fasteners by forming a durable barrier against moisture, chemicals, and environmental exposure. Zinc is one of the most widely used and cost-effective coatings for protecting metal fasteners from corrosion. It provides reliable sacrificial protection and a clean, uniform appearance, making it suitable for a broad range of components. There are a few different types of Zinc corrosion-resistant coatings:
Zinc Electroplating with Blue / Yellow / Thick Layer Passivation (CrVI)-free
Zinc electroplating is a versatile and economical coating process that deposits a thin layer of zinc onto metal fasteners to provide sacrificial corrosion protection. The addition of blue, yellow, or thick-layer passivation enhances the coating’s resistance to white rust and extends service life—all without the use of hexavalent chromium (CrVI). This makes it an environmentally responsible option for a wide range of applications.
Product Features
- Excellent sacrificial corrosion protection
- Available finishes: blue, yellow, or thick-layer passivation
- CrVI-free (hexavalent chromium free) for regulatory compliance
- Uniform, bright appearance suitable for visible assemblies
- Cost-effective for screws, bolts, nuts, washers, studs, and rivets
Mechanical Zinc Plating with Blue / Yellow / Thick Layer Passivation (CrVI)-free
Mechanical zinc plating applies a protective zinc layer without the risk of hydrogen embrittlement, making it ideal for high-strength steel fasteners. Parts are placed in a barrel with proprietary chemicals, zinc powder, and glass beads, then tumbled to mechanically bond the zinc to all exposed surfaces. This CrVI-free coating provides uniform coverage and reliable corrosion protection for components with simple geometries.
Product Features
- Eliminates hydrogen embrittlement risk for high-strength fasteners
- Uniform zinc coverage through mechanical bonding process
- Available finishes: blue, yellow, or thick-layer passivation
- CrVI-free and environmentally compliant
- Suitable for fasteners and components with simple geometries
- Compatible with post-treatments similar to electroplating
Zinc Flake Coating (CrVI)-free
Zinc flake coatings are non-electrolytic systems designed to provide exceptional corrosion protection without the risk of hydrogen embrittlement, making them suitable for high-strength steel fasteners. The coating consists of zinc and aluminum flakes suspended in a binder, applied as a liquid through a dip-spin or spray process, then baked for a durable finish. These CrVI-free coatings comply with ISO 10683 standards and deliver long lasting protection in demanding environments.
Product Features
- Non-electrolytic application prevents hydrogen embrittlement
- Complies with ISO 10683 zinc flake coating standards
- Excellent corrosion resistance and uniform appearance
- Contains zinc and aluminum flakes for durable, sacrificial protection
- Optional inorganic or organic topcoats for enhanced performance
- Not recommended for threaded parts ≤ M5 or fasteners with small internal drives
- CrVI-free and environmentally compliant
Hot Dip Galvanizing
Hex head screw hot dip galvanizedHot-dip galvanizing is carried out by dipping the parts in molten zinc at temperatures of over 530°C. Immediately after dipping, a centrifugal process is used to remove the excess zinc, reducing the thickness of the zinc layer to values around 40 - 60 µm. The corrosion protection from hot dip galvanizing lasts much longer than electroplating zinc due to the greater coating thickness. However, the resulting zinc layer thickness requires special thread dimensions / tolerances, and is only feasible starting from thread size M8 and up.
Product Features
- Exceptional corrosion protection through thick zinc coating
- Complies with ISO 10684 hot-dip galvanizing standards
- Zinc layer thickness typically between 40–60 µm
- Provides significantly longer service life than electroplated zinc
- Requires adjusted thread tolerances due to coating thickness
- Recommended for thread sizes M8 and larger
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