Black Oxide Coating Problems

To achieve maximal corrosion resistance the black oxide must be impregnated with oil or wax.

Black oxide coating problems.

We use a high temperature black oxide to finish a number of different tools a couple of these tools have joints with a tight fit. We find that 30 40 of the tools show salt bleed out at the joints. Instead the black oxide coating is produced by a chemical reaction between the iron on the surface of the ferrous metal and the oxidizing salts present in the black oxide. Aluminum and copper in ultra blak 400 baths or other black oxide solutions.

Control buildup of sludge red iron oxide zinc. As advantageous as this supplementary feature undoubtedly is black oxide failure does occur so we need to stay abreast of the common problems incurred by this oxidizing process. There s an issue with the ebony hued conversion coating. Black oxide is a conversion coating formed by a chemical reaction produced when parts are immersed in the alkaline aqueous salt solution operated at approximately 285 degrees f.

Black oxide hi temp application. Black oxide or blackening is a conversion coating for ferrous materials stainless steel copper and copper based alloys zinc powdered metals and silver solder. Only the inspector s pen is wavering. The finish should be oily black.

Many more letters about black oxide and room temperature blackening can be found by searching the site. Assessing process variables as with any high end engineering process numerous variables are at work during a black oxide coating sequence. If the residue is sodium or potassium salts it is likely that it came from the black oxide process. 563 south leonard street waterbury ct 06708 1 203 756 5521 1 203 756 9017 contact us online p o.

The tools are thoroughly rinsed and soaked in hot water an extended period of time. Many jobshops offer black oxide services. Box 790 waterbury ct 06720. It is used to add mild corrosion resistance for appearance and to minimize light reflection.

Avoiding excessive sludge and chemical buildup. The black oxide process is a chemical conversion coating. The reaction between the iron of the ferrous alloy and the hot oxide bath produces a magnitite fe3 o4 on the actual surface of the part. Putting a tick in that checkbox the coating should also be moderately corrosion resistant.

This means that the black oxide is not deposited on the surface of the substrate like nickel or zinc electroplating. Where to get it done. Curtis you could confirm the source of the white residue by carefully scraping some of it off the parts and analyzing it. One of its advantages over other coatings is.

Please go to our directory of jobshops and search for the term black oxide.