Chemical Solutions

Trivalent Black Over Zinc

The Metalline ZnB trivalent black chromate process will produce a glossy deep black conversion coating over acid and alkaline zinc plated parts as well as activated zinc die castings. With proper maintenance and effective rinsing, the Metalline ZnB trivalent black process can consistently achieve 120 hours to 5% white salts per the ASTM B117-19 salt spray corrosion test.

  • Excellent black finish over acid chloride zinc plated deposits
  • Effectively blackens zinc die castings without plating them
  • Contains no hexavalent chrome
  • Requires high protection trivalent chrome sealer


Metalline ZnB zinc blackening process:

  • Metalline Preblack used to condition acid or alkaline zinc plated deposits prior to blackening
  • Zinc die castings are cleaned and activated prior to blackening
  • Thoroughly rinsing between process solutions is critical to prevent cross contamination
  • Metalline ZnB blackening immersion times range from 60 to 180 seconds
  • Metalline ZnB operating temperature ranges from 110 – 130F
  • Metalline Koretard® XTC trivalent chrome sealer can provide up to 120 hours of corrosion protection