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The Lumiclad process from Birchwood Casey forms a non-dimensional black oxide finish on all aluminum surfaces, and is designed to be clean, durable and tightly adherent to metal substrate.
The finish has an inherent lubricity that aids in break-in and resists galling, making it an ideal finishing choice for product assemblies with sliding contacts. The company claims that aluminum machine components, such as piston/cylinder assemblies, actuator mechanisms, slides and valve assemblies achieve smoother break-in.
The finish offers excellent conductivity and break-in lubricity in a protective black finish that is simple and economical to apply. The 30-minute process develops a uniform coating thickness of .000060 inches (1.5 micron) that will not close down hole diameters or change critical part dimensions. The black finish is smooth, clean and electrically conductive, making it an apt coating choice for assemblies requiring a chassis ground.
The process delivers a smooth, satin-black finish with a slightly porous crystal structure that absorbs an optional topcoat, such as clear polymer, light oil or dry-to-touch sealant. Birchwood Casey says that prior to the development of this new blackening process, the complex process of black anodizing had been the only viable blackening option for manufacturers of aluminum components.
Though the protective properties of a black anodized finish are high, often they are higher than the application requires and they come at additional cost. By contrast, the company says, this process uses a conventional immersion tank process line. It is designed to be easy and safe to operate so that manufacturers can operate it in-house themselves, thereby eliminating the need for outside processing. For most applications, a seven-tank line and a 30-minute process time does the job from start to finish.