General Metal Finishing

Fumetrol® 21

Non-PFOS Mist Suppressants

Functional Chrome
General Metal Finishing

Controlling Fumetrol® 21

Control of Fumetrol® 21 in chrome plating baths

is simple. The easiest method is to measure 

the surface tensions of the chrome plating 

bath and then make additions of Fumetrol® 21 

when required.

The two common methods employed for surface

tension measurements are surface tensiometers or stalagmometers. Both systems can 

be used with Fumetrol® 21.

PFOS Content of a Chrome Plating Bath after Slide Conversion to Fumetrol® 21

0

10

20

30

40

50

60

70

80

90

100

12345678

Normalized PFOS concentration

Months

It took only 7 months to reduce the PFOS content to only 1% of the original level*

* This is the experience at one plating company. Results may vary depending on several factors, including tank size, 

 work load, drag-out etc.

Converting to Fumetrol® 21

The normal implementation of Fumetrol® 21 is 

to make a simple slide conversion. This is 

made by stopping the addition of the existing 

fume suppressant and by making additions of 

Fumetrol® 21 to maintain the surface tension 

within the required range for complete mist 

suppression.

Independent analysis has shown the positive 

benefits on the PFOS content of a chrome 

plating bath of such a slide conversion using 

Fumetrol® 21.
Hard Chrome Plating 

with Non-PFOS Mist 

Suppressant

Even though the hard chrome plating of parts 

imbues them with special characteristics like 

improved wear resistance, superior corrosion 

resistance, better tribological properties etc. 

the process itself has some weak points. The 

hard chrome plating process uses chromic 

acid which is a compound listed as being toxic. 

Due to the low current efficiency of even the 

best process, the majority of electrical energy 

supplied goes to electrolyzing the water in the 

solution. 

These two effects combined mean that considerable amounts of bubbles are generated 

at the anodes and cathodes, which can create 

a toxic mist as they burst upon the surface of 

the bath. 

Due to the volume and the fineness of the mist 

produced, this can create a health hazard for 

people and can contaminate equipment in the 

vicinity of the plating bath. This issue is wellknown and there are several methods available 

to avoid this issue. One of the easiest and bestknown measures is to use a suitable mist / fume 

suppressant.

Typical Hydrolysis during Chrome Plating Anode Cathode

Anode

C

athode

Anode

Cathode

Chromic acid mist

Bubbles due to hydrolysis
Function of Mist 

Suppressants

The pervasiveness of the mist is due to the 

energy that the droplets have when they are 

formed from bubbles bursting on the surface. 

The energy is a factor of the size of the bubbles and the surface tension of the liquid they 

are carried in. If the surface tension of the 

bath is reduced then this significantly minimizes the formation of mist. When the surface tension is brought below a key value, typically 35 

dynes/cm, then the generation of mist is so low 

that it is no longer considered a health risk and 

the contamination of equipment is effectively 

eliminated.

Formation of Mist Droplets (Jets) 

from Electrolysis Bubbles

The resulting speed of a droplet (jet) can be 

up to 10 m/s

Mist droplets from a chrome plating bath 

without fume suppressant 

Mist 

droplets

Notice the large amount of staining on the surroundings due to chromic acid mist when no 

mist suppressant is employed. This was after 

only 3 minutes of plating. The surroundings 

remained clean even after several hours of 

plating when either type of mist suppressant 

was employed.

No mist suppressant

With mild foaming mist suppressant

With low foaming mist suppressant
Mist Suppressants 

and PFOS

Mist suppressants are highly stable surfactants 

that are added to the chrome plating bath to 

greatly reduce the surface tension. Many 

fume suppressants for hard chrome plating 

baths have been typically based on PFOS 

(Perfluoroctanesulphonate).

PFOS is a very chemically resistant chemical 

and so is ideal for use in harsh environments 

like hot chromic acid plating baths. Unfortunately, 

the extremely robust nature of PFOS means 

that it is not easily biodegraded or waste treated 

and so is released into the environment where it 

builds up. PFOS has been classified as persistent, bioaccumulative and toxic (PBT) for some 

years now.

The negative health effects of PFOS on animals 

and humans have been studied and as a result 

are unacceptable. PFOS has been banned in the 

EU and will be banned in the USA and Canada 

when an alternative is found. The EU directive 

2006/122/EC relates to the restrictions on the 

marketing and use of certain dangerous substances and preparations. This came into effect 

on June 27, 2008. The main aim of this directive 

is to ensure ultimately the phase­out of uses of 

PFOS. Due to the awareness of the HES risks 

the use of PFOS has declined by over 95% in 

the last decade, leaving only a few specialized 

applications. 

There is currently an exemption for hard chrome 

plating (annex 3c of 2006/122/EC). However, 

there are several communities, organizations, 

and authorities that are campaigning for a complete ban on the use of PFOS.

With Fumetrol® 21, Atotech has developed a 

non­PFOS mist suppressant alternative.

Fumetrol® 21 fully complies with the non­PFOS 

criteria. Fumetrol® 21 is a stable product, not 

prone to breakdown in hard chrome plating 

baths and has been proven in production since 

2006. 

General Metal Finishing
Atotech Main Office

Erasmusstr. 20

D­10553 Berlin

Phone +49 (0)30 349 85 0

Fax +49 (0)30 349 85 777

 www.atotech.com 

11/09_ JR

Fumetrol® 21 – 

Features and Benefits at a Glance

▪ Non­PFOS formulation 

▪ Virtual elimination of chromic acid mist in 

the work area 

▪ Lower chromium replenishment costs as a 

result of reduced drag­out and spray loss 

of plating solution 

▪ Less chance of contamination to adjacent 

plating solutions and equipment by chromic 

acid mist 

▪ Increased life of ventilation system and 

other plating room equipment 

Fumetrol® 21 is a proven, robust and effective 

non­PFOS mist suppressant for the hard 

chrome plating industry. Its ease of operation, 

simple conversion of old systems and high 

stability makes it the ideal choice for reducing 

the environmental impact as well as helping to 

comply with ever more stringent wastewater 

restrictions.

By replacing PFOS mist suppressants with 

Fumetrol® 21, Atotech in partnership with its 

customers is able to play its part in reducing the 

environmental impact of hard chrome plating 

on the planet, while maintaining the protection 

of its plating personnel.