Different Types of Metal Finishes

Metal finishing is the final step in the manufacturing process used to provide aesthetics and environmental protection. It is also used to reduce surface roughness beyond the capabilities of machining operations for parts that must mate or seal. It also includes methods of metal cleaning, descaling, deburring, etc. In short, numerous types of metal finishing processes are used for a variety of purposes. This guide reviews some major finishing methods, as well as applications and considerations for choosing a metal finishing process. Some of the general advantages of metal finishing treatments include:

  • Increased durability
  • Improved decorative appeal
  • Enhanced electrical conductivity
  • Higher electrical resistance
  • Higher chemical resistance
  • Higher tarnish resistance
  • Types of Metal Finishing
  • Below are a few of the types of finishing processes available:

Metal plating uses chemical baths to coat or alter the surface of substrates with thin layers of metal such as zinc, nickel, cadmium, or chromium. The electroplating method generates an electric current to coat the substrate, while electroless plating employs an autocatalytic process in which the substrate catalyzes the reaction. As plating is a chemically intensive, large scale process, it is almost invariably performed by plating service providers who specialize in the field.

Metal plating can improve a product’s durability, corrosion resistance, surface friction, and exterior appearance. In the case of galvanized metal, the zinc plating serves as a sacrificial anode, itself corroding while protecting the integrity of the underlying substrate. However, plating machines are generally not suited for smoothing out surface defects.

Sherardizing is a process used to coat small steel parts such as bolts and washers with a corrosion-resistant zinc-iron alloy. Parts are tumbled in a heated drum containing zinc dust, producing a highly corrosion-resistant finish. In high-volume production runs, a barrel-finishing machine is a fast and efficient coating solution.

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