MF Tech Insights

Choosing Between Nickel and Zinc For Fastener & Spring Plating

Written by Metal Finishing Technologies | Jan 11, 2023 7:58:00 PM

When it comes to fastener plating and spring plating, zinc and nickel sulfamate are the two most common selections. However, they are not equivalent in their properties, costs, or results. Before you opt for either nickel or zinc plating of fasteners, springs, and other small parts, take a few moments to compare their benefits and limitations.

 

PROS

CONS

Properties of:

Zinc Plating Fasteners
  • Corrosion-resistant 
  • Extremely low cost and substantially less expensive than nickel
  • Wide variety of finishes including polished, brushed, and various colors through chromate coatings
  • Alloys well with other metals to enhance corrosion resistance 
  • Lightweight
  • Anodic to steel, galvanically protecting it (which reduces the risks of a thinner plate)
  • Best suited for low- to moderately-corrosive environments 
  • Performance can degrade under high temperatures unless appropriately treated 
  • Achieving consistent thickness in zinc coating can be challenging 
  • A “sacrificial” coating that wears down over time
  • A tough material, but less so than nickel

Properties of:

Nickel Sulfamate Plating Fasteners
  • A highly resilient plate
  • Can be deposited in thick plates (an inch or more)
  • A low-stress deposit that avoids most peeling, cracking, crazing, warping, blistering, distortion, and shrinkage typical of other processes
  • Highly pure (typically 99.9% nickel) 
  • Fast, reliable, and produces highly consistent results 
  • Resistance to high temperature (1400 C melting point) 
  • Good thermal transfer capabilities 
  • High tensile strength 
  • Easily machinable and solderable 
  • Excellent ductility and elongation without deformation or stress cracking 
  • More expensive than zinc
  • Cannot be chromated in other colors (although it can be polished to a bright sheen)
  • A less preferred alternative to cadmium in aerospace & defense than zinc plating
  • Cathodic to steel. Any pin holes or gaps in the plate can result in rust blooms from a galvanic reaction.

 

Zinc plating of fasteners is the preferred method for general-purpose corrosion protection, versatility, and the most cost savings. Nickel sulfamate fastener and spring plating is a more robust option for extremely corrosive environments or applications where heat resistance, total strength, and long-lasting durability under stress are important.

Electrolytic vs. Electroless Nickel For Fasteners & Springs

Zinc vs. nickel is not the only choice to make, however. You have options when it comes to nickel plating, as there are both electrolytic and electroless processes for application of the plate.

Electroplated nickel is deposited in much the same way as a zinc plate, through an electrical reaction that draws free nickel molecules to the surface of your fasteners or springs in a liquid bath. “Electroless” nickel accomplishes this without electricity, through a purely chemical reaction.

While electroplating can be faster and create a thicker coating, it’s less uniform and prone to a certain level of “dog-boning.” This is where the resulting plate is thicker around the edge and convex corners and thinner around the concave corners. Electroless nickel provides an unparalleled and consistent finish without dog-boning — a truly uniform plate thickness that is important in close-tolerance applications. Consider carefully whether this will matter to your springs or fasteners before deciding.

Fast Quotes From a Metal Finishing Expert

In the market for zinc spring plating services? Do you need nickel fastener plating for commercial or industrial hardware? Contact Metal Finishing Technologies today for any of the types of plating discussed above from a team that prioritizes fast turnarounds and superior service.

MFT’s team of experts can offer you personalized guidance on the considerations that should weigh on your choice of zinc, electroless nickel, nickel sulfamate, or another plating for springs and fasteners. Our team has decades of experience and a customer-centered mission. Just share the details of your project and request a quote!
View full post