5 Things to Consider When Choosing a Metal Coating and Finish


The right metal coating plays a vital part in how well a piece of equipment will perform its intended function. This holds true for any piece of equipment used in any industry, from ventilators and other medical equipment to vehicle parts. Some of the most common coatings and finishes used today include:

  • Paint: Giving your products a coat or two of the right kind of paint can prolong their life and optimize them to better suit their function. Paint is particularly ideal when you would like to alter the color or surface quality of the product quickly, or require versions of it that are finished in various colors. Besides liquid paints that can be easily applied to a surface, you can have your product finished with powdered paint, or painted electronically.
  • Chemical coating: This method provides your product with a thin layer of sulfide and oxide coating by causing a chemical reaction on its surface. This type of coating is ideal if you need to protect a metallic surface on a product from corrosion.
  • Physical Vapor Deposition (PVD): In this method, a vapor material is condensed to create a thin coating on a product’s surface. There are various techniques through which this PVD can be achieved, but sputtering is the most commonly used method of turning a material into a vapor. In some instances, you will find PVD coatings combined with other techniques to produce a coating of the required standard.
  • Electroplating: This technique involves submerging the metal to be coated in a bath containing another melted metal (mostly cadmium, nickel, chrome or an alloy of two or more metals). The thin coat of metallic particles created offers adequate protection against corrosion.

When it comes to selecting the right metal coating and finishing solutions, there are several factors that you need to consider.

1. Abrasion

How hard is the metal you’re trying to coat? Softer metals like copper, brass, silver and gold require less abrasion than harder metallic carbides derived from tungsten, titanium or vanadium. These substances are used to fabricate machines and are therefore built for durability. Techniques like grinding are better suited to harder metals, which also require tougher abrasives to produce the right quality of finish.

Abrasives are the materials used to make the wheels of the grinding machines, which are then employed to smooth other metallic surfaces. Different kinds of grinders use different abrasives to achieve varying levels of smoothness.

2. Corrosion

If you are producing metals that will be used outdoors or exposed to moisture, you will need a finish that can protect the metal from rust. If you’re creating surfaces or pieces of equipment on which chemicals are likely to spill, they will need to be resistant to corrosion.

Chemical coating is ideal for scenarios in which surfaces will be exposed to corrosion. Metal plating, especially the sherardizing process, also creates corrosion-resistant nuts, bolts, pipes, and so on by coating them with a zinc-iron alloy. Finishes that prevent tarnishing are ideal for parts or equipment that will be exposed to the elements or chemicals.

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3. Conductivity

For certain parts, equipment, and products that need to transfer electricity effectively, you’ll want conductive finishing. Electroplating is used to produce parts that have the right level of conductivity for the situation. Different metals produce different conductivity values when used for electroplating.

An element’s degree of conductivity is measured by its %IACS value. The higher the value, the higher the element’s level of electrical conductivity. If you’re in the business of manufacturing semiconductors, you will be looking to have your components electroplated in gold or silver to achieve the specific conductivity required.

4. Strength and Malleability

If you require a component to be especially strong, you need to select a coating or finish that will improve its hardiness. One of the finishing techniques that is effective in achieving this is heat treatment. It is what gives the teeth of gears their firmness. Inductive or flame heating enhances the wear resistance of a surface while simultaneously hardening it.

If malleability is important to the products you manufacture, you will want to coat them with tin or silver, as these are among the softer metals.

5. Aesthetics

A painted finish allows you to create products in the color of your choosing. This type of finish gives you a lot of flexibility in terms of the aesthetic qualities you want your products to have. Plating your products in chrome, brushed nickel or gold is also ideal for aesthetics as it will give them an attractive luster.

The Bottom Line

There is one more important consideration you need to think about as you select a metal coating and finish: to be able to make money on the products you’re creating, you need to keep production costs low. Once you’ve selected the finish that provides you with the functional and aesthetic qualities you’re seeking, be sure you’re able to secure it at a price that works for your company.


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