Zinc Plating Options: How to Choose the Best Finish for Your Application

Zinc plating is a popular metal finishing process because it is efficient to apply, durable, and adds corrosion protection for parts used in many automotive, industrial, and other applications. There are different types and methods of zinc plating, so it’s important to choose the right option depending on application requirements.

New Method Plating specializes in zinc electroplating. Learn more about the benefits of zinc, different types of zinc plating, and how this process is used across industries and applications.

An Overview of Zinc Plating and Its Benefits

Zinc plating entails applying a layer of zinc to metal surfaces to improve their resistance to corrosion and rusting. The layer forms an effective barrier between the underlying material and moisture, chemicals, and other contaminants that can cause damage over time.

Zinc is commonly applied with an electroplating process, in which cleaned and treated metal parts are submerged in an electrolyte solution (i.e., acid zinc or alkaline zinc) along with a piece of zinc. DC current is applied, causing the zinc to oxidize and give up ions. These ions disperse into the solution, then collect on the parts, forming a uniform coating. Depending on the parts’ size, shape, and application requirements, they can be tumbled in a barrel of solution or submerged in a stationary tank.

Some advantages of choosing zinc for plating include:

• Improved corrosion resistance.
• Good adhesion and ductility for superior coverage.
• Aesthetic appeal.
• Electrical conductivity.
• Compatibility with paint.
• Cost savings compared to other finishes or processes.

Types of Zinc Plating

Different types of zinc plating provide different levels of corrosion and environmental protection for parts and equipment. Three of the most common types are clear, yellow, and black zinc plating.

Clear Zinc Plating

Also called silver or blue zinc plating, this process includes both plating and treatment with a chromate conversion coating that adds moderate corrosion resistance. Because the coating is clear, the natural silver color of the zinc remains visible. This is a good choice for use with parts that do not have specific color requirements.

Yellow Zinc Plating

Yellow zinc plating is achieved by coating the parts with yellow chromate. This adds a distinctive yellow or gold color, greater corrosion resistance than clear plating, and protection against oxidation, which in turn improves the useful life of the part. Yellow chromate can be either hexavalent or trivalent. While hexavalent yellow chromates have been banned by the EU Restriction of Hazardous Substances (RoHS) Directive, trivalent yellow chromate alternatives are RoHS-compliant, with lower toxicity and environmental impact.

Black Chromate Zinc Plating

Black chromate zinc plating is used for many heavy-duty applications exposed to corrosive or harsh environments. It is also popular for its aesthetic appeal due to its dark, matte finish.

This option is common in automotive, construction, defense, and electronics applications, where it provides excellent protection as well as a glare-free surface. The finish may be prone to scratches or wear marks in some applications. Black chromate comes in both hexavalent and trivalent versions.

Applications Across Industries

There are many applications that require zinc plating to extend the useful life of parts and equipment, including:

• Aviation and aerospace: Adds corrosion and temperature resistance to parts and fasteners.
• Automotive: Reduces rates of rust for fasteners, bolts, nuts, and vehicle parts.
• Construction: Hardware and fasteners plated with zinc resist rust and corrosion from moisture, weathering, and salt spray.
• Electronics and electrical parts: Zinc improves electrical conductivity in connectors, terminals, and contact plates.
• Industrial machinery: Improves temperature and rust resistance in nuts, bolts, screws, and hardware in heavy equipment.
• Medical equipment: Used to prevent corrosion in metal parts on hospital beds, wheelchairs, and walkers; also used to coat surgical instruments and non-implantable orthopedic and similar devices.

Choose New Method Plating for Zinc Finishes

Zinc plating is a cost-effective, durable, and environmentally friendly way to protect parts and add an aesthetic appearance. We offer custom zinc plating using clear, yellow, or black chromate zinc coatings to meet your project specifications.

To learn more about our zinc plating capabilities, contact us today to discuss your project or request a quote for pricing details.