Phillips Head Chipboard Screw

Zinc-Plated Screws (White Zinc Coated Screws)

Zinc-plated screws, often referred to as "white zinc screws" due to their characteristic light, silvery finish, are fasteners treated with a protective zinc coating to enhance durability and corrosion resistance. This plating process is one of the most common and cost-effective methods for safeguarding metal screws, making them widely used in various industries and everyday applications.

Plating Process

The zinc coating is typically applied through electroplating: the screws are submerged in a zinc-rich electrolyte solution, and an electric current is passed through the setup. This causes zinc ions to bond to the screw's surface, forming a thin, uniform layer (usually 5–25 micrometers thick). The result is a bright, silvery-white finish-hence the term "white zinc"-that acts as a physical barrier between the underlying metal (often steel) and environmental factors like moisture, oxygen, and chemicals.

Yellow zinc-plated screws are fasteners coated with a zinc layer that undergoes a passivation treatment to achieve a distinctive yellow or golden finish. This plating process enhances both corrosion resistance and aesthetic appeal, making them a popular choice for applications where moderate protection against the elements and a polished look are required.

Plating Process

The core plating method is similar to standard zinc plating: screws (typically made of carbon steel) are electroplated with a layer of zinc to form a protective base. The key difference lies in the post-plating passivation step: after zinc plating, the screws are treated with a chromate-based solution (often containing hexavalent or trivalent chromium). This chemical reaction creates a thin, yellowish conversion coating on top of the zinc layer, which seals the zinc and boosts its resistance to corrosion. The result is a uniform, golden-yellow finish that gives these screws their name.

Black-plated screws are fasteners coated with a dark, often matte or glossy black finish, designed to enhance both aesthetics and, in some cases, corrosion resistance. The black coating can be applied through various processes, each tailored to specific functional or visual requirements, making these screws popular in applications where appearance and subtlety are key.

Plating Processes

The black finish is achieved through several common methods, depending on the desired durability and look:

Black Zinc Plating: Similar to standard zinc plating but with a post-treatment (e.g., using black chromate or dye) to darken the zinc layer. This process offers basic corrosion resistance and a uniform black appearance.