{"id":22217,"date":"2023-11-07T18:14:45","date_gmt":"2023-11-07T16:14:45","guid":{"rendered":"https:\/\/fractory.com\/?p=22217"},"modified":"2024-01-26T12:59:06","modified_gmt":"2024-01-26T10:59:06","slug":"black-oxide-coating-explained","status":"publish","type":"post","link":"https:\/\/fractory.com\/black-oxide-coating-explained\/","title":{"rendered":"Black Oxide Coating – How It Works, Benefits & Types"},"content":{"rendered":"

Black Oxide coating is a type of chemical conversion coating mainly for ferrous metals but the process is adapted for stainless steel, copper, aluminium and zinc. Conversion coatings are different from conventional coatings, such as powder coating<\/a> or electroplating, as they do not add or remove any metal from the substrate.<\/p>\n

Instead, black oxide finish converts the surface layer of a part into one that boasts a great appearance, exhibits greater corrosion resistance and is non-reflective. The process is also often referred to as blackening, black passivating<\/a>, oxidising and gun bluing<\/a>.<\/p>\n

What Is Black Oxide?<\/strong><\/h2>\n

Generally, black oxide or black iron oxide refers to the oxide of iron known as magnetite (Fe3O4) that is formed when a ferrous metal is exposed to special oxidising chemicals. It is a type of conversion coating, thus the surface layer of a metal is formed into its oxide through conversion. The layer thickness on a finished part is between one and two micrometres.<\/p>\n

The thin layer or coating along the part’s surface provides advantages such as greater corrosion protection, an attractive look and a smooth finish<\/a>. As a result, many applications such as automotive parts use the black oxide coating process.<\/p>\n

The blacking process works for some non-ferrous metals, such as zinc and copper, as well.<\/p>\n

When Is Black Oxide Coating Used?<\/strong><\/h2>\n

Black oxide coatings are used to increase corrosion and wear resistance while complying with high tolerance requirements<\/a>. One of the advantages this process offers is the minimal buildup which means that the overall dimensions of the part only increase by a miniscule amount.<\/p>\n

It is used on parts that require a certain degree of abrasion resistance as the black oxide does not wear away as easily as some other finishes. Black oxide parts are often used in the automotive and aerospace sectors in addition to being used in producing hand tools and other hardware. It is used to coat fasteners<\/a> as black oxide finish improves their grip and corrosion protection while making them aesthetically pleasing.<\/p>\n

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How Does the Black Oxide Coating Process Work<\/strong><\/h2>\n

The black oxide coating or blackening process is a chemical reaction in which the outer surface of a metal reacts to chemical solutions and therefore undergoes transformation.<\/p>\n

The process is divided into three main types:<\/p>\n