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Metal Finishing Services

3 Types of Blacking

chemical blacking ukblack oxide coatingblackening copper

Chemical Blacking is a popular options for customers looking for a matte black finish that will enhance corrosion resistance without causing dimensional changes. Silchrome Plating offer 3 varieties of chemical blacking for different materials.

Also Known As…

Chemical Blacking is a process known by a number of different names. It is often referred to as Black Oxide Coating and Blackening, all of which are more or less the same process, with a metal being placed in an electrolytic bath where a chemical reaction changes the properties of the metal’s surface. Unlike in electroplating where an amount of material is added on top of the metal, chemical blacking is a conversion coating that will have a negligible effect on the dimensions of the part.


Chemical Blacking is a popular choice with tool and machine parts such as chains, sprockets, gears, hydraulic blocks, fasteners, and increasingly with components used outdoors. Chemical Blacking will only offer a moderate amount of corrosion resistance, even when combined with an oil or rust inhibiting lubricant, but will certainly increase protection against oxidation. Chemical Blacking is often selected when customer’s want a non-reflective matte black finis that will not degrade under UV light.

3 Processes We Offer

The three Chemical Blacking processes that we offer are for three different types of material:

Carbon Steels: Where a chemical reaction is achieved between the ferrous metal and oxidising salts

Stainless Steels: For Stainless Steels we offer Hot PX3 Blacking in which Sodium Hydroxide is combined with an oxidising agent such as sodium nitrate. This produces a chemical reaction between the Iron in the Ferrous alloy and converts the surface of the steel into magnetite.

Copper Alloys: Silchrome have an Ebonal process for Copper and Copper Alloys, for this process to work it needs to have at least 65% Copper in them. In this process the Copper reacts to the salts in the bath to form Cupric Oxide.

Silchrome are fully ISO 9001 and 14001 certified and carry out all of our metal finishing processes from our modern facility in Leeds, West Yorkshire.

  • The official logo for the Surface Engineering Association.
  • The official logos for the ISOQAR and UKAS industry regulatory bodies.
  • The official logo for the Institute of Materials Finishing.
  • The official logos for the ISOQAR and UKAS industry regulatory bodies.