Too glossy, not black enough… fastening elements must have certain characteristics, which have more to do with design than with their functional characteristics.

This is according to “The Notion of Appearance in Coatings,” a white paper from Bossard Group, an internationally active fastener technology and logistics company.

This requirement is ever more frequently added to traditional characteristics — such as resistance to corrosion, mechanical resistance, and dimensional requirements. However, the solution cannot be limited to just one color, or a level of gloss. It must also take into account the primary function of the coatings.

Resistance to corrosion, dimensional compatibility, preserving the strength of the base materials — these are the principal functions. In fact, several functions can be involved in coatings: the esthetic element; the brilliance, the color, and the roughness, which will allow the fastening element either to be seen, or to blend in with the assembly.

Coating choices
A familiar  example of “appearance” are nickel-plating and chrome-plating. For ages, the esthetic coatings of choice have been nickel-plating and chrome-plating, which are deposited onto steel and copper-based metals. The iridescence and brilliance allow for coatings that are often compatible with industries that have little to do with mechanics, such as interior design, health management, luggage. — and which are used on screws, rivets, and special fasteners.

These coatings are relatively costly as the price of the materials based on Ni and Cr are high; however, the vat based electrolytic process allows one to moderate the manufacturing costs.

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This release was originally posted on Fastener Fair USA, North America’s fastest-growing expo for the fastener industry. The event was recently rescheduled to March 2021 in Cleveland, OH. Learn more here.