Selecting the proper coating for your fasteners can be difficult. While many of our customers specify and know with great certainty the coating that will work for them, others may need some assistance in making a decision.
The primary purposes of coatings is to provide corrosion resistance, protection and in some cases, lubricity. Taking in to consideration the performance requirements you are looking to obtain, the part that is being coated, the conditions of the operational environment and a whole host of other factors, Branam can help you find the right plating, coating or finish. With the right choice you can really pull a lot of performance and longevity from your specialty and stock fasteners.
Fasteners that have been zinc plated can have a shiny silver, gold, or sometimes bluish appearance, and are deal for providing protection in mildly corrosive conditions. They're fairly corrosion-resistant but will rust if the coating is destroyed or if exposed to a marine environment. The layer of plating is anywhere from 1μm to 100 μm thick. This is the most widely used and common fastener coating and can serve as a good basecoat for other platings.
Zinc / Nickel
This mixed metal plating option provides better anti-corrosive properties that zinc only plating. It functions as a "sacrificial coating" that breaks down before the base material. Zinc-nickel is used to plate fasteners for use in high corrosion areas (under the hood and chassis joints of automobiles). It can also be used in electronic, aerospace and defense applications. It often serves as a safe replacement for cadmium plating. Available in clear, yellow and black.
Serves both a decorative and engineering function. The material provides high-corrosive resistance and can be applied through an electroplating or spin coating process.
A plating that is commonly used in conductive environments like automotive weld and pipe-hanging applications. Because of its bright, shinny appearance, this plating can also serve as an identification aid. As an assembly is moving down the production line, line workers can more easily spot the fastener and perform any necessary steps that involve the welded part.
Cadmium plating is an excellent corrosion protector and has been in military and aviation specs for many years. It is also widely used in locking fasteners because of its lubricious nature. Cadmium bolts are often written in to specs and accompanied by phos and oil bolts.
It is a sacrificial coating for the steel fastener, and readily takes a chromate conversion coating which improves the corrosion resistance many times over. Its galvanic characteristics are compatible with aluminum and it also posses ideal softness and malleability properties. No substitute offers all the properties of cadmium.
A chemical process that transforms the surface of the steel/iron. Black oxide converts this most outer layer to black rust magnetite or Fe3o4. The process contains no heavy metals, so it is considered environmentally friendly way of providing corrosion protection, anti-galling properties and a paintable surface if needed.
Phosphatizing (AKA phosphating or phosphate conversion coating)
A pretreatment process that provides corrosive resistant properties and prepares the steel fastener to be later painted or coated with zinc, nickel and other product. It is not a traditional surface coating as it is a chemical process that structurally changes the outside layer of the part.
An ultra-thin coating about .0002”-.0004”. It provides fasteners with a highly corrosion-resistant finish. Often specified by auto manufacturers because it is a chrome-free coating that is widely accepted by environmental organizations and the European ELV. It’s available in clear, black and yellow.
A coating created with overlapping zinc and aluminum flake brought together with a chromium binder. It prevents rust in steel, cast iron and other ferrous metal parts. Fully banned in all products sold in Europe and Japan.
Similar to Dacromet in that it contains overlapping zinc and aluminum flakes. However it is brought together with inorganic, non-chromium binder - making Geomet® ideal for applications where environmental concerns are prevalent. The coating possesses a silver-metallic look and provides rust-preventative finish. More costly than Dacromet® and requires two coats
A fluoropolymer dry film lubricant used on fasteners and coated bolts to prevent corrosion, provide heat and wear resistance and give some lubrication and controlled friction properties. Many of the Xylan family of coatings contain PTFE or other lubricants in them.
A dry film lubricant that in addition to resisting corrosion, also reduces friction and wear that comes in the form of galling and fretting. It is biocompatible, ESD controlled and has a number of chemical resistance properties. In addition to industrial applications, Everlube may be ideal for meeting a number of electronics manufacturing, bio-medical and chemical processing requirements.
For those not tied to a specific brand of dry film lube, Branam offers its own proprietary formulation that can provide many of the performance characteristics you seek.
Waterborne coatings that provide the perfect combination of physical properties and corrosion resistance, and are specified by many major automotive and truck manufacturers for coated fasteners.
Magni / DorrItech
A line of chome-free duplex coatings. Many of the 500 series products for fasteners offer superior corrosion resistance through an inorganic applied zinc-rich basecoat and an organic aluminum-rich topcoat. The basecoat protects against heat resistance and provides stability while the topcoat can be finely tuned for chemical resistance, galvanic corrosion resistance, friction and other performance requirements. Different coatings available in wide range of colors including black, gold, silver, blue and others.