Trivalent chromium black passivation for zinc-iron plating


  • Contains trivalent chromium and produces a more shiny black appearance compared to conventional agents.
  • Ideal black passivation for zinc-iron plating.
  • Offers extended service life, lower replenishment rate and more attractive appearance compared to conventional passivation agents.
  • Corrosion resistance lasts from 120hr - 168hr and more with no white rust.
  • Does not contain silver or dyes.

The benefits described above are results obtained at YUKEN, and performance in customer environment should be verified separately.

Product Specifications


Appearance Dark blue strongly acidic liquid (METASU YFK-IAA)
Red strongly acidic liquid (METASU YFK-IBA)

Bath makeup conditions

Chemicals used Usage range
METASU YFK-IAA 30 – 90ml/L
METASU YFK-IBA 60 – 120ml/L

Usage conditions

Item Range Remark
Process temperature 30 – 50°C
Process time 40 – 60 seconds
pH 1.6 – 2.2 Verify pH value before usage. Use caustic soda or hydrochloric acid for adjustment if pH value falls outside of the specified range.
◎ The pH value must be adjusted to 1.8 during bath makeup.
Agitation Yes In the case of basket processing, use vibratory agitation.
In the case of rack processing, use air agitation or vibratory agitation.

Replenish conditions

Chemicals used Replenishment reference (standard)
METASU YFK-IAA 30mL/100dm2
METASU YFK-IBA 50mL/100dm2
Synthetic hydrochloric acid pH adjustment



Inquiry about the product

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