Common metal finishing processes

Electroplating

Electroplating involves depositing a thin layer of metal onto the surface of a workpiece through an electrochemical process. This technique is primarily used to improve corrosion resistance, increase surface hardness, and enhance the appearance of parts. In the aerospace industry, electroplating is vital for components that require precise conductivity or protection from extreme environmental conditions.

Anodizing

Anodizing is an electrochemical process that converts the metal surface into a durable, corrosion-resistant, anodic oxide finish. This is particularly useful for aluminum parts, making it a staple in aircraft manufacturing. Anodizing increases corrosion resistance and wear and provides better adhesion for paint primers and glues than bare metal.

Chemical Film Coating (Chromate Conversion)

Chemical film coating, or chromate conversion, is a process that provides a protective layer on aluminum and its alloys. The coating offers corrosion resistance and electrical conductivity and serves as an excellent primer for paint. This method is extensively used in the aerospace industry to protect the exterior surfaces of aircraft and spacecraft from harsh environmental factors.

Powder Coating

Powder coating is a finishing process in which a powder material is sprayed onto a surface and then cured under heat to form a hard coating. This method is renowned for its high-quality, durable finish, offering superior resistance to chipping, corrosion, and fading. Powder coating is ideal for a wide range of applications, including aircraft interiors, equipment housings, and defense machinery.

Shot Peening

Shot peening is a cold working process used to produce a compressive residual stress layer and modify metals’ mechanical properties. By bombarding the surface of a part with small spherical media, shot peening significantly increases fatigue strength and resistance to stress-corrosion cracking. This technique is crucial in prolonging the lifespan of critical aerospace components under fatigue stress.

Passivation

Passivation is a non-electrical process that removes free iron from the surface of stainless steel parts, enhancing their corrosion resistance. This process is vital for components exposed to corrosive environments, especially in the aerospace and defense sectors, where reliability and longevity are paramount.

Electropolishing

Electropolishing is an electrochemical process that smoothens and streamlines the microscopic surface of a metal object. This technique not only improves the aesthetic brightness but also increases corrosion resistance and reduces surface irregularities. Electropolishing is particularly useful for components requiring high cleanliness and durability in aerospace applications.