Passivation ADL-32, chromefree direct use in quench tank

AD Chemicals metal surface treatment logo
  • Chromium-6 free; based on chromium trivalaent
  • For direct use in the quench tank
  • Excellent white rust protection

Passivation ADL-32 is a hexavalent chrome free water-based conversion coating for freshly galvanised steel surfaces. Passivation ADL-32 forms a transparent to slightly visible layer that gives an improved corrosion resistance of the galvanised steel surface. A galvanised steel surface that has been pre-treated with Passivation ADL-32 does not give white rust under normal storage conditions. The surface has a low electrical resistance. 

hdg chromefree passivation


Contact us for more information

+31 (0) 167 526 900

The best chromefree passivation available

Passivation ADL-32 is tailored to the needs of galvanizers. Next to excellent white rust protection we have ensured that bath maintenance is easy and stable.

Passivation ADL-32 product characteristics:

  • Passivation layer on fresh galvanized steel
  • Chrome(III) based
  • Protection against white rust
  • Direct use in quench tank
  • Provides bare corrosion resistance during storage and transport
  • Competes easily with Chrome (VI) based pre-treatments
  • Free of substances of very high concern

For direct use in the quench tank

Passivation ADL-32 can be used directly in the quench tank. See the image with the process overview.

chromefree passivation adl32

Customer case: Verzinkerij Meerveldhoven (Netherlands)

Verzinkerij Meerveldhoven is one of the first galvanizers that made the switch to Passivation ADL-32 of AD Chemicals. Previously they used a polymer based passivation product after the last cooling bath. This polymer based solution caused smut formation when used at >70⁰C. With Passivation ADL-32 this defenitely isn’t the case, it can be used at high temperatures, even boiling water is not an issue. Next to that it can be used directly in the quench. Ensuring easy implementation. The white rust protection is also outperforming the previous passivation product.

Test Results

Passivation ADL-32 has been thoroughly tested according to the highest test standards. Below pictures show vefore and after NSS the results obtained with Passivation ADl-32.passivation chromefree adl-32

hexavalent chromefree passivation

Test Results Humidity

Passivation ADL-32 test results for 24-hours of humidity testing

chromefree test results humidity hdg passivation

Passivation ADL-32 versus Chromate passivation

The following table shows an overview comparison between Passivation ADL-32 and a chromate (hexavelent) passivation.

Chromate conversion coatingPassivation ADL-32
Environmental impact-/-++
Passivation performance (white rust prevention)++++
Chemical basischromium(VI), toxicchrome(III)
Robust and easy to handle proces++++
Meets quality standardsYes, industry standardCompetes easily with chromium(VI) based passivations
Direct use in quench tankYESYES
Use after cooling bath (first cooling than passivation)YESYES
Appearanceyellow, clear layerclear layer
Waste water treatmentMultiple steps, chrome reduction requiredRegular waste water treatment
Easy to strip passivation of substrate when needed?NOYES
Pricing€€ slightly more expensive

Exceeding the market standard

HDG Passivations have a huge range of requirements on a complex combination of zinc based alloys. This drives the need for close working relationships, consultation, testing and pilot line experimentation. With Passivation ADL 32 ADChemicals shows that replacing chromium-6 while maintaining the highest quality is possible.