Coating

Black Oxide

Black Oxide

The black oxide process offered by Parker Trutec MMI is a conversion coating for ferrous metal parts. It is used to add mild corrosion resistance, for appearance and to minimize light reflection. To achieve maximal corrosion resistance the black oxide must be impregnated with oil or wax. One of its advantages over other coatings is its minimal buildup. Hot blackening involves dipping the part into various tanks. These tanks contain, in order, alkaline cleaner, water, caustic soda at 140.5 °C (the blackening compound), and finally the sealant, which is usually oil. The caustic soda bonds chemically to the surface of the metal, creating a porous base layer on the part. Oil is then applied to the heated part, which seals it by “sinking” into the applied porous layer. It is the oil that prevents the corrosion of the workpiece. There are many advantages of blackening, mainly:

  • blackening can be done in large batches (ideal for small parts)
  • no significant dimensional impact it is far cheaper than similar corrosion protection systems, such as paint and electroplating
  • very low cost

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Parker Trutec’s MMI, Tennessee and Arkansas facilities offers world class black oxide services serving customers in the Midwest and Southern regions. We provide the convenience and flexibility your company needs to meet the demanding requirements of today’s manufacturing environment.