Glossary

A corrosion-resistant finish where metallic zinc is deposited on the fastener’s surface through electroplating. This is followed by a black trivalent chromate treatment that enhances both appearance and corrosion protection. A Zinc Black Trivalent finish is often used when a fastener needs to be both visually appealing and resistant to corrosion.

Appearance - A Zinc Black Trivalent plating results in a smooth, glossy black surface with a uniform finish.

Zinc Clear Trivalent is a corrosion-resistant finish where metallic zinc is first deposited on the fastener’s surface through electroplating. This is followed by a clear or colorless trivalent chromate treatment, which adds an extra layer of corrosion protection. Together, these provide up to 72 hours of salt spray resistance, making it a reliable finish for many applications. The trivalent chromate is also a safer and more environmentally friendly alternative to older hexavalent chromium finishes.

Appearance - Fasteners with this finish have a distinct silver color with a slight blue tint. Overseas platers often produce a dull silver tone, while U.S. platers may enhance the finish with blue brighteners for a glossy, chrome-like appearance.

A corrosion-resistant coating made from a mixture of zinc and aluminum flakes, typically applied using a dip-spin process. This finish produces a matte black appearance with a rough, uneven texture similar to Zinc Flake Silver. This coating is designed to provide high corrosion protection without the risk of hydrogen embrittlement. Making Zinc Flake Black ideal for high-strength fasteners used in demanding environments.

Appearance - This coating has a matte black finish with a slightly rough, uneven surface.

Zinc flake coating is a non-electrolytic finish made of zinc and aluminum flakes in a binder, applied by spraying or dipping and then cured with heat. Despite being thin, it offers very high corrosion resistance, often exceeding 1,000 hours in salt spray testing. It eliminates the risk of hydrogen embrittlement, making it especially suitable for high-strength fasteners and critical applications in industries like automotive and aerospace.

Blog Post: What Are Zinc Flake Coatings and Why Are They Important

Zinc Flake Silver (Magni 501) is a chrome-free, zinc-rich coating applied to fasteners primarily via a dip-spin process. Designed as a high-performance alternative to traditional zinc platings, it provides excellent corrosion resistance without the risk of hydrogen embrittlement.

Appearance - This finish typically appears as a dull gray, less textured than hot-dipped galvanized, yet still somewhat rough and uneven.

Zinc Olive Drab is a corrosion-resistant finish where metallic zinc is first deposited on the fastener’s surface through electroplating. This is followed by an olive drab chromate treatment, traditionally hexavalent, that enhances corrosion protection and provides a darker, low-glare appearance. While originally developed for military use, it is also used in other applications that require both protection and a subdued finish. Due to environmental regulations like the European Union’s RoHS directive, which restricts hexavalent chromium, trivalent alternatives are now more commonly used in RoHS-compliant applications.

Appearance - Fasteners with a Zinc Olive Drab finish typically appear dull green to olive in color, often with an iridescent sheen that may reflect shades of purple, pink, or bronze depending on the lighting. This finish is darker and more muted than Zinc Yellow, but the iridescent effect can be visually similar

Zinc coating is a metallic layer of zinc applied directly to steel through processes like electroplating, hot-dip galvanizing, or mechanical plating. The zinc protects the steel by corroding first (sacrificial protection). Coating thickness varies depending on the method, and it provides reliable corrosion resistance but can be prone to hydrogen embrittlement on high-strength parts.

Zinc Yellow is a corrosion-resistant finish where metallic zinc is first deposited on the fastener’s surface through electroplating. This is followed by a yellow hexavalent chromate treatment that provides enhanced corrosion protection, often offering up to 120 hours of salt spray resistance. However, due to environmental regulations such as the European Union’s RoHS directive, the use of hexavalent chromium is restricted in some markets, leading to the growing use of trivalent chromium as a safer alternative.

Appearance - Fasteners with a Zinc Yellow finish have a bright, golden-yellow color that can show iridescent shades of green, pink, or purple, depending on the lighting. This finish tends to be more vibrant and colorful than its trivalent counterpart. 

Zinc Yellow Trivalent is a corrosion-resistant finish where metallic zinc is first deposited on the fastener’s surface through electroplating. This is followed by a yellow trivalent chromate treatment that enhances corrosion protection while meeting environmental and safety standards. It provides a safer alternative to traditional hexavalent finishes.

Appearance - Fasteners with this finish have a bright yellow or gold color, often showing iridescent hints of green, pink, or purple depending on the lighting. Generally, fasteners with a Zinc Yellow Trivalent finish have a less vibrant color compared to traditional hexavalent Zinc Yellow finishes.

A zygologist is an expert in the science of fastening and joining, also known as zygology. In practical terms, a zygologist specializes in understanding how parts are connected — whether through bolts, screws, rivets, adhesives, or other fastening methods — and recommends the best solution for each application. While not a common job title today, it essentially describes a fastener or joining technology specialist.

Zygology is the scientific study of how things join together — in other words, the science of fastening and joining.

The word comes from the Greek root zygon (meaning “yoke” or “joining”). In practice, zygology covers the methods, technologies, and principles behind mechanical fastening, bonding, welding, and other ways materials are connected.

In the fastener industry, the term is sometimes used more broadly to describe the engineering discipline of fastening solutions — essentially the knowledge of which fastener, coating, or joining technique is best for a given application.