Substitution of sodium chromate as an anticorrosion agent of the carbon steel in sealed circuit of gas absorption appliances

One of the goals of the European REACH regulation is the progressive replacement of substances of very high concern (e.g. carcinogens) by safer alternatives. Companies that use these substances, actively search for safer alternatives (less dangerous substances, new technologies and processes), and report about these alternatives. Below you will find the information on possible alternatives for chromium trioxide, included in the different applications for authorisation received so far by ECHA. To obtain further details, please follow the link to the full dossier.

Below you can find possible alternatives for sodium chromate as an anticorrosion agent of the carbon steel in sealed circuit of gas absorption appliances.

Sodium Chromate

EC-number: 231-889-5
CAS-number: 7775-11-3
Use: Sodium chromate as an anticorrosion agent of the carbon steel in sealed circuit of gas absorption appliances up to 0.70% by weight (as Cr6+) in the refrigerant solution
Technical function: Anticorrosion agent

Alternatives:
Different (groups of) companies have researched possible alternatives to replace chromium trioxide. Even if these alternatives may not have been chosen for their particular case, they may still be an appropriate option for other cases.

Soluble silicon compounds
Rare earth metal salts (REMS)
Molybdate
Nitrite
Zinc containing corrosion inhibitors
Strong alkaline solutions
Phosphates and phosphonate compounds
Inhibitor 7 (cfr. Dometic GmbH application)
Technical alternative: Replacement of GAHP technology – Electrical heat pumps
Technical alternative: Replacement of GAHP technology: Condensing boiler

More detailed information

All research efforts by companies have been documented in reports. The following ECHA-dossiers are available about possible alternatives for sodium chromate as an anticorrosion agent of the carbon steel: