11/09_ JR 

# 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 10 0

12345678Normalized PFOS concentration



# M onths

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 con

siderable 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 well

known and there are several methods available

to avoid this issue. One of the easiest and best

known mea sures is to use a suitable mist / fume

suppressant.



# Typical Hydrolysis during Chrome PlatingAnodeCathodeAnodeCathodeAnodeCathode 

# 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 bub

bles and the surface tension of the liquid they

are carried in. If the surface tension of the
bath is reduced then this significantly minimiz

es the formation of mist. When the surface ten

sion 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 sur

roundings 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 sub

stances and prepara tions. This came into effect

on June 27, 2008. The main aim of this directive
is to ensure ultimately the phase

­ out 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 com

plete ban on the use of PFOS.

With Fumetrol ® 

# 21, Atotech has developed a

non ­PFOS mist suppressant alternative.

Fumetrol ® 

# 21 fully complies with the non

­ PFOS

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.com11/09_ JR



# Fumetrol ® 

# 21 –

Features and Benefits at a Glance

▪ Non

­ PFOS 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

non

­ PFOS 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.