Glossary Burnishing screws

Burnishing screws is a process that is frequently used in industry and trade to protect and improve screw surfaces. But how exactly does the black oxidation of screws work and what advantages does it offer?

Burnishing is a surface treatment of metal parts in which a thin layer is created on the surface of the metal through chemical reactions. This layer protects the metal from corrosion and wear and improves its optical properties.

Why are screws burnished?

Screws made of ferrous metal can be subject to corrosion and wear depending on their intended use. Burnishing forms a protective layer on the screw surface, which prevents corrosion and wear and extends the service life of the screws. Burnishing also improves the optical properties of the screws and gives them a dark, rich color.

How are screws burnished?

Burnishing screws can be carried out in various ways, including dipping the screws in a solution of chemicals or using electrolysis. A common method is to immerse the screws in a solution of nitric acid and copper sulphate. The screws are then immersed in a solution of iron(III) chloride, which creates the protective layer on the surface of the screw.

The exact process of burnishing screws depends on the type of screw and the desired surface finish. Screws must be thoroughly cleaned before they are black-finished to ensure that the protective coating is even and durable.

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