Trivalent chromium black passivation for alkaline rack plating


  • Passivation agent that contains trivalent chromium to give a black appearance.
  • Uniform black appearance and high corrosion resistance can be obtained consistently.
  • Non-chelating type enables easy removal of heavy metals by sedimentation.
  • Conventional chromating equipment can be used.
  • Long service life with excellent operational performance.
  • Uniform color tone can be obtained as intensity of reaction produces little variation in color tone.

Product Specifications


Appearance Dark green strongly acidic liquid (METASU YFB-ZA)
Dark red strongly acidic liquid (METASU YFB-ZB)
Dark red strongly acidic liquid (METASU YFB-ZBR)

Bath makeup conditions

Chemicals used Usage range
METASU YFB-ZA 30 – 80ml/L
METASU YFB-ZB 50 – 120ml/L

Usage conditions

Item Range Remark
Process temperature 35 – 45°C
Process time 40 – 70 seconds
pH 1.6 – 2.2 Verify the pH value before usage. Use caustic soda or hydrochloric acid for adjustment if pH value falls outside of the specified range.
Agitation Yes Use air agitation or pump agitation.

Replenish conditions

Chemicals used Replenishment reference (standard)
METASU YFB-ZA 3 – 5ml/100dm2
METASU YFB-ZBR 7 – 15ml/100dm2
Synthetic hydrochloric acid pH adjustment



Inquiry about the product

Feel free to contact us if you have any questions or matters to discuss.