Black Oxide Coating Problems

One of its advantages over other coatings is.

Black oxide coating problems.

To achieve maximal corrosion resistance the black oxide must be impregnated with oil or wax. Aluminum and copper in ultra blak 400 baths or other black oxide solutions. 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. This means that the black oxide is not deposited on the surface of the substrate like nickel or zinc electroplating.

Black oxide hi temp application. There s an issue with the ebony hued conversion coating. Avoiding excessive sludge and chemical buildup. Box 790 waterbury ct 06720.

Black oxide or blackening is a conversion coating for ferrous materials stainless steel copper and copper based alloys zinc powdered metals and silver solder. 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. Control buildup of sludge red iron oxide zinc. Solving iron copper and zinc contamination problems.

The tools are thoroughly rinsed and soaked in hot water an extended period of time. Many more letters about black oxide and room temperature blackening can be found by searching the site. Many jobshops offer black oxide services. Achieving a cleaner deeper black finish.

The finish should be oily black. 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. We find that 30 40 of the tools show salt bleed out at the joints. Curtis you could confirm the source of the white residue by carefully scraping some of it off the parts and analyzing it.

563 south leonard street waterbury ct 06708 1 203 756 5521 1 203 756 9017 contact us online p o. 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. Putting a tick in that checkbox the coating should also be moderately corrosion resistant. A problem solving guide for black oxide coatings that s the direction this article is taking.

The black oxide process is a chemical conversion coating. Only the inspector s pen is wavering. If the residue is sodium or potassium salts it is likely that it came from the black oxide process. 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.

Assessing process variables as with any high end engineering process numerous variables are at work during a black oxide coating sequence.