Barrel Plating Services

Zinc Plating

Zinc Plating

An economical coating which provides moderate corrosion resistance.

Zinc Nickel Plating

Zinc Nickel Plating

Superior corrosion resistance at a premium price. You get what you pay for!

Alkaline Zinc Nickel

Alkaline Zinc Nickel

Benefits of the alkaline zinc nickel process include improved ductility and thickness distribution, making it especially suitable for certain types of parts.



Many treatments affect the properties of our coatings. Examples include corrosion resistance, color, and torque-tension, among others.

Zinc (Zn) Plating

Zinc plating was developed, and continues to evolve, to meet the most challenging corrosion protection, temperature, and wear resistance requirements. Electroplating of zinc was invented in 1800 but the first bright deposits were not obtained until the early 1930s with the alkaline cyanide electrolyte. Much later, in 1966, the use of acid chloride baths improved the brightness even further.
The latest modern development occurred in the 1980s, with the new generation of alkaline, cyanide-free zinc.

Recent European Union directives (ELV/RoHS/WEEE) prohibit automotive, other original equipment manufacturers (OEM) and electrical and electronic equipment manufacturers from using hexavalent chromium (CrVI). These directives, combined with increased performance requirements by the OEM, has led to an increase in the use of alkaline zinc, zinc alloys and high performance trivalent passionate conversion coatings.

WPC uses the acid chloride process to provide the most effective mixture of brightness, efficiency, and corrosion resistance. We also partner with industry-leading chemical suppliers to utilize high performance trivalent passivates and sealers which maintain compliance with the strictest of industry standards.

Acid Zinc Nickel (ZnNi) Plating

Zinc Nickel plating is one of the best corrosion-resistant finishes available, offering over 5 times the protection of conventional zinc plating and up to 1,500 hours of neutral salt spray test performance. This is achieved with a relatively thin & uniform coating thickness, with no thread or recess fill which may be present with thicker organic coatings attempting to meet the same corrosion resistance.

Forms of the ZnNi process include Low Ni (5~10% Ni) and High Ni (10~18% Ni), using Alkaline or Acid bath chemistry. Wolverine exclusively uses High Nickel, and uses Acid bath chemistry in three of our four ZnNi plating lines.

The Acid process advantages include improved cathode efficiency and brightness, typically at a lower chemical cost than Alkaline. WPC is able to provide bright, semi-cosmetic Acid ZnNi, similar to the appearance of acid Zinc but with many times the corrosion resistance.

Alkaline Zinc Nickel

Wolverine Plating is excited to announce we are in the final stages of completing a new Alkaline Zinc Nickel plating line. The plating line will be completely automated and fully integrated with a continuous bake oven and a robotic post treatment system. Including the cost of expanding our facility and the new equipment Wolverine will have invested more than $10.0 million on this project.

Benefits of the Alkaline Zinc Nickel process include improved ductility and thickness distribution, making it especially suitable for certain types of parts. The Alkaline process is also widely specified by the automotive and other industries, which will allow Wolverine to perform new plating specs and expand into new markets, including automotive fasteners.

Please view the nearby video which shows a timelapse highlighting the initial installation of our new barrel plating line and robotic post treatment system.

New Barrel Plating Line Install – Timelapse


Today, the vast majority of plated material gets a post-treatment of some kind, whether to affect corrosion resistance, lubricity, color, or adhesion properties, among many others.

Trivalent Chromates/Passivates

Clear: WPC provides trivalent passivates for both Zinc-Nickel and Zinc plated parts. The most common and best performing is Tri-Clear. In the years since Hex Chrome has been phased out, Trivalent Clear passivates have become the industry standard for both appearance and corrosion resistance.

Black: WPC also provides black passivates for both Zinc-Nickel and Zinc. While the color is mainly used for identification and not cosmetics, our process can yield semi-cosmetic finishes, especially for Zinc-Nickel.

Yellow: WPC can also provide a tri-yellow passivate for Zinc only (not Zinc-Nickel). This color is reminiscent of hex dichromate, and as such is becoming less and less common since most industries have moved away from the hex finish. The dye used to make the passivate yellow can impair the corrosion resistance, so tri-clear has become the best option in terms of appearance and corrosion resistance.

Color Dyes

WPC offers several dye colors for identification (not cosmetics). Our inventory includes Red, Orange, Green, Blue, and Violet dyes.


WPC has a wide range of sealers, both inorganic and organic, to improve the corrosion resistance of our base finishes.

Waxes / Torque Modifiers

WPC has several OEM-approved torque/friction modifying topcoats which can be applied directly over the plating, or after other post-treatments such as passivates or sealers.


WPC has worked closely with a major automotive Tier 1 supplier in developing the use of a proprietary Rubber-To-Metal-Bond Adhesion-Promoter topcoat. When used over our ZnNi process, the topcoat assists in the subsequent overmolding processes without sacrificing the corrosion resistance of the base ZnNi plating.

Baking for H.E. 

Hydrogen embrittlement (H.E.) describes the embrittling of metal after being exposed to hydrogen. It is a complex process that is not completely understood because of the variety and complexity of mechanisms that can lead to embrittlement.

Acid Pickling and Zinc Electroplating are both processes which have been linked to HE under certain conditions, and baking for prescribed durations has been specified as a remedy. WPC is equipped with multiple HE relief baking ovens to ensure susceptible parts are properly baked during processing.

Robotic Post Treatment Demonstration

Have Questions About Pre-Treatments for your Metal Part? or Don’t Know if Your Part Needs a Post-Treatment?

The experts at Wolverine Plating Corporation can help.