Surface finishing is a key method for adding value to a component. Both functional and decorative finishing can add value to a product by increasing functional performance or enhancing product appearance. But what exactly are the differences between functional and decorative finishes?
Functional finishes are meant to be just that: functional. Their purpose is to improve component performance, which could include durability; hardness; chemical, tarnish, UV, and corrosion resistance; wettability; solderability; surface friction; or electrical or resistance conductivity. A common functional finishing process for metal components is passivation. Passivation is a process which increases the corrosion resistance of metals. Components are cleaned, then immersed in an acidic bath which creates a protective coating on the surface of the part. Ferrous metals, including steel and stainless steel, are not impervious to rust and corrosion, and components made from these materials can be made more corrosion resistant and durable through passivation.
Decorative finishes enhance the appearance of a component with their luster, texture, and color. Some decorative finishing processes include PVD, electroplating, brushing/mechanical highlighting, powder coating, lacquer coating, and vibratory finishing. Decorative finishes are found throughout the consumer market in automotive (which is basically synonymous with chrome), kitchen and bath, appliances, home hardware applications and more. Myriad items from drawer pulls to steering wheels receive decorative finishes.
While decorative finishes such as chrome plating and physical vapor deposition (PVD) offer some performance characteristics, the primary purpose of a decorative finish is aesthetic; some decorative finishing processes do not enhance component durability or performance. For example, while chrome plating, in addition to its visual appeal, also can enhance corrosion and chemical resistance, processes such as brushing (mechanical highlighting), which creates a unique pattern on the surface of the component, are purely for looks. Chrome finishes (both hexavalent and trivalent chrome) for automotive applications on the outside of a vehicle, such as a hubcap, grille, or emblem, have to meet performance benchmarks for corrosion, as these components are exposed to corrosive forces in the environment like road salt.
The choice to apply a functional or decorative surface finish to a component depends upon its location and function. Consumer-facing products need to be visually appealing to customers, but they also need to maintain functional performance—a showerhead needs to look good, but it also needs to resist rust and corrosion—which makes decorative finishing a good way to add value. For parts where function and performance trump all, such as engine and machine components, a functional finish can increase component longevity by enhancing corrosion resistance and other essential properties.
ECF offers both functional and decorative finishing for a variety of substrates and applications. Call us today to see how our finish and process offerings align with your surface finishing needs.