Jul 16, 2026News & Insights

Chain Surface Finishes: A Guide to Galvanized, Eco-Friendly, and Dual-Layer Coatings

This article covers the most common chain surface treatments, with a deep dive into galvanizing options and the growing demand for eco-friendly solutions

The surface finish of a chain is not just about aesthetics — it determines how well the chain resists corrosion, complies with environmental regulations, and performs in its intended application.

Common Surface Finishes for Chains

At Boyuan Metal, we offer a full range of surface treatments to suit different applications, environments, and budgets:

Surface Finish	Description	Typical Application
Self-Colored (Raw)	Natural steel finish, no protective coating	Indoor use, further processing
Polished & Oiled	Polished surface with a light oil film for temporary protection	Display chains, decorative hardware
Black Oxide (Bluing)	Chemical blackening with oil protection	General hardware, low-light applications
Spray Painting	Color paint applied to the surface	Decorative chains, color coding
Electro-Galvanized	Thin, uniform zinc layer applied via electroplating	Retail hardware, general outdoor use
Hot-Dip Galvanized	Thick zinc layer applied by immersion in molten zinc	Construction, marine, heavy-duty outdoor use
Electrophoretic Coating (E-Coat)	Uniform paint-like coating applied electrically	Automotive parts, premium hardware
Powder Coating	Dry powder electrostatically applied and baked	Decorative chains, outdoor furniture

Among these, electro-galvanized and hot-dip galvanized are by far the most commonly specified finishes, offering the best balance of cost and corrosion protection.

Do Galvanized Chains Come with Certification?

A question we increasingly receive from European and North American customers is: "Is your galvanizing certified?"

In the Chinese chain market, there is no universal third-party certification specifically for galvanizing. What we offer instead — and what most customers find more practical — is salt spray testing according to ISO 9227 or ASTM B117 standards. This measures how long the zinc coating withstands a corrosive saline environment before red rust appears.

Common test durations include:

Test Duration	Suitable For
24 hours	Indoor or light-duty outdoor use
48 hours	General outdoor applications
72 hours	Demanding outdoor and industrial environments
100+ hours	Marine, coastal, and highly corrosive environments

We tailor the galvanizing process to meet the salt spray hours specified by each customer, ensuring the finish matches the actual application rather than imposing a one-size-fits-all solution.

Electro-Galvanized Chains: The Eco-Friendly Standard

To comply with the EU's RoHS and REACH directives, the industry has shifted to trivalent chromium (Cr³⁺) passivation, commonly known as eco-friendly galvanizing. Today, the vast majority of electro-galvanized chains on the market already use the Cr³⁺ process.

Zinc Layer Thickness

For electro-galvanized chains, the zinc coating thickness typically ranges from 8 to 12 microns. This provides a clean, bright, silver-white finish suitable for most retail and general-purpose applications.

Hot-Dip Galvanized Chains: Heavy-Duty Corrosion Protection

For applications demanding maximum corrosion resistance — such as construction sites, marine environments, and outdoor infrastructure — hot-dip galvanizing is the preferred choice.

The zinc layer on hot-dip galvanized chains typically reaches 50 to 80 microns, several times thicker than electro-galvanized coatings. The thicker the zinc layer, the longer the chain withstands harsh conditions before rust appears.

For marine and offshore applications, some customers require a zinc coating thickness exceeding 80 microns. At Boyuan Metal, we can apply thickened hot-dip galvanizing to meet these demanding specifications.

Comparing Electro-Galvanized and Hot-Dip Galvanized

Dimension	Electro-Galvanized	Hot-Dip Galvanized
Zinc Layer Thickness	8–12 microns	50–80+ microns
Appearance	Bright, smooth, silver-white	Matte grey, slightly rougher texture
Corrosion Resistance	Moderate — suitable for general outdoor use	Excellent — suitable for marine and heavy industrial use
Cost	Lower	Higher
Passivation	Cr³⁺ eco-friendly passivation standard	Passivation optional; thick zinc layer provides primary protection
Typical Applications	Retail hardware, DIY chains, light outdoor use	Construction, agriculture, marine, offshore

A Premium Option: Hot-Dip Galvanized + Electro-Galvanized Dual Coating

Some customers require both superior corrosion resistance and a bright, attractive finish — for example, for architectural hardware, high-end playground equipment, or decorative marine applications.

For these cases, we offer a dual-layer process: hot-dip galvanizing followed by electro-galvanizing. This combines:

The thick, durable zinc base of hot-dip galvanizing for long-term rust protection

The smooth, shiny appearance of electro-galvanizing for visual appeal

The result is a chain that performs in harsh environments while looking as clean as a retail product.

Summary: How to Choose the Right Finish

Your Priority	Recommended Finish
Lowest cost, indoor use	Self-colored or black oxide
General outdoor, retail packaging	Electro-galvanized (Cr³⁺ eco-friendly)
Heavy-duty outdoor, construction	Hot-dip galvanized (50–80 microns)
Marine and offshore	Hot-dip galvanized (80+ microns, thickened)
Corrosion protection + bright appearance	Hot-dip + electro-galvanized dual coating
Decorative, color required	Powder coating or spray painting

Boyuan Metal supplies chains with all the surface treatments described above, from standard finishes to custom dual-layer coatings. Tell us your application and requirements — we will recommend the right finish for your market.