Field Notes

Choosing the Right Fastener Finish: A Guide by your Field Engineers

Written by Field Fastener | August 07, 2025

Selecting the correct finish for your fasteners is as crucial as choosing the metal itself. A finish can impact corrosion resistance, installation torque, performance, appearance, and longevity. Here’s an engineered breakdown of the most common finishes we source across our global supplier network, why they matter, and where they’re typically used.

Plain / Self-Color (Uncoated Steel)

A raw steel finish with no plating—sometimes called "self-color." Suitable for indoor, non-corrosive environments or short-term use. Not recommended for outdoor or harsh conditions.

Use Cases:

  • Structural bolts used in interior connections
  • Temporary assembly hardware

Black Oxide (Chemical Black / Black Japanned / Bluing)

A thin oxide layer produced chemically (black oxide) or via lacquer (black japanning). Offers mild corrosion resistance, reduces surface reflectivity, and is dimensionally stable.

Use Cases:

  • Tooling components
  • Indoor connections

Phosphate (Zinc, Iron, or Manganese Phosphate)

A crystalline coating formed via acid solution treatment. Often impregnated with oil or wax. Offers baseline corrosion protection from the oil or wax, good paint adhesion, and negligible hydrogen embrittlement.

Use Cases:

  • Painted parts
  • Brake systems
  • High-friction joints

Electro-Zinc (Commercial Zinc Plating)

A sacrificial zinc layer applied by electroplating. Inexpensive and widely available. Effective in mild-to-moderate corrosive conditions, but higher-strength steels risk hydrogen embrittlement unless baking is applied.

Use Cases:

  • Consumer products
  • Indoor enclosures
  • Light industrial equipment

Zinc Nickel Alloy Plating

An alloy plating offering superior corrosion resistance. Good for highly corrosive environments and industrial or automotive usage.

Use Cases:

  • Outdoor assemblies
  • Automotive underbody assemblies
  • Aerospace fasteners

Hot-Dip Galvanized

Thick zinc coating obtained by dipping parts in molten zinc. Offers robust corrosion protection. Not recommended for small-diameter threads with internal drives.

Use Cases:

  • Outdoor structural bolts
  • Utility pole hardware
  • Marine applications

Zinc Flake / Non-Electrolytic Zinc-Organic Systems (DIP-SPIN)

An advanced coating combining zinc flake with a thin organic top-coat. Outstanding corrosion resistance, precise friction control, and zero hydrogen embrittlement risk.

Use Cases:

  • Automotive chassis fasteners
  • Wind turbine structural bolts
  • Critical assembly bolts in outdoor equipment

Nickel Plating (including Copper Strike + Nickel)

A dense, metallic coating that improves corrosion resistance and appearance. Common in high-temperature settings.

Use Cases:

  • Exhaust clamps
  • Decorative hardware
  • Heat-treated fasteners

Chrome / Hard Chrome Plating

A thin layer of chromium applied by electroplating. Known for aesthetic sheen and abrasion resistance.

Use Cases:

  • Hydraulic assemblies
  • Engine hardware
  • Decorative trim screws

Electro-Brass Plating

A decorative brass layer applied via electroplating. Offers warm appearance and moderate corrosion protection.

Use Cases:

  • Architectural hardware
  • Light fixtures
  • Furniture screws

Additional Specialty Coatings

Anodizing: (for aluminum components): Thickened oxide layer for abrasion and corrosion resistance.

Use Cases:

  • Electronics housing screws
  • Aerospace-grade aluminum fasteners
  • Marine applications with lightweight requirements

Gold Plating: Provides electrical conductivity and oxidation resistance.

Use Cases:

  • Circuit board connectors
  • Precision electronics
  • Luxury hardware

PTFE / Ceramic or Organic Electrocoats: Used when low friction, lubrication or chemical resistance is required.

Use Cases:

  • Fasteners in chemical plants
  • Fasteners requiring torque control
  • Non-stick or low-maintenance systems

How Field Can Help You Choose

With access to over 900 global suppliers and more than 120,000 SKUs, Field has the scale and engineering insight to recommend finishes that optimize for:

  • Corrosion resistance & lifespan
  • Hydrogen embrittlement control
  • Joint friction & torque predictability
  • Availability, cost-efficiency & supply reliability

Whether your application demands exterior durability, assembly color match, or high-torque performance with minimal friction variation, our value-added engineering team and VMI programs can help specify the best finish for your application.

 

Summary of Common Finish Choices:

  • Plain steel: lowest cost, minimal protection
  • Black oxide / japanned: mild protection, indoor use
  • Phosphate: paintable, basis-level corrosion
  • Electro-zinc: moderate protection, prone to embrittlement unless baked
  • Zinc nickel: better corrosion resistance than Electro-Zinc
  • Hot-dip galvanize: heavy-duty outdoor protection
  • Zinc flake systems: next-gen performance, precision friction control
  • Nickel & Chrome: decorative, high-temp or wear applications
  • Brass, Anodized, Gold: specialty/coordinated or precision use cases

 

Looking for help choosing the right fastener finish? Contact Field Fastener’s engineering team today at fieldfastener.com.