In documenting the essential characteristics of the black oxide coating process, we’ve illustrated the engineering science and the main advantages of the procedure. More than a smart finishing process, a material depositing technique; the metal surfaces that undergo this process are actually converted into a new form, one that shields the underlying metal while gifting it with a superb onyx-black finish. Now, on knowing that we’ve satisfied the basics, let’s take a closer look at one specific benefit, an anti-corrosion feature that benefits countless industrial domains.
Graded Anti-Corrosion Properties
Hot and cold blackening techniques deliver contrasting corrosion properties. For example, a standard room temperature procedure produces a black oxide coating with nominal anti-corrosion features, but the hot process delivers a more uniform finish, a coating that’s far more resistant to corrosion. Alternatively, these two techniques can be further reinforced. Post-processing stations apply supplementary coatings, oils that dictate just how rustproof the part will be once it has passed the after-finish stage.
Unlike electroplating technology and several of the other corrosion-resistant techniques on the market, the black oxide method partners with anti-corrosive aptitude with a bundle of other tempting features. First of all, and this feature makes a lot of sense if the parts are manufactured according to high-tolerance engineering standards, the process only converts the surface. It doesn’t add to that surface. In effect, dimensional stability is retained.
Metal components are intended for a whole host of applications, some of which will incur physical deformations. A blackened component won’t suffer from abrasions or scratches, mechanical intrusions that would remove a deposited finish and expose the underlying ferrous or non-ferrous surface. Instead, the black oxide layer is part of the original metal, which means it exhibits the same strength as the original alloy.
When a fastener, machine part, or other metal component oxidizes, its microcrystalline structure alters and becomes coarse. The screw thread of the fastener is next to impossible to tighten or loosen, the metal part deteriorates, and material is sacrificed to the oxidizing process. Black oxide coatings reverse this trend by adding a matte black lubricated finish, a layer of slip-enhanced mechanical fortitude.
It helps to remember that the word “oxide” features prominently in this coating procedure. The blackening salts are designed to purposefully control an oxidizing regimen, a finishing technique that shields the metal from corrosive influences. Additionally, the option to add a post-finish oil really enhances this water-resisting feature.