You are on page 1of 4


Zinga is a unique form of corrosion protection because it provides both Active and Passive
protection in a form that's as easy to apply as paint...BUT Zinga is not paint.
Zinga is an active zinc performance coating which works in conjunction with the metal
beneath whereas paints are only passive barriers. Regardless of how thick paints are
applied, they remain as barriers. Once they are breached corrosion sets in immediately.
Despite this significant difference, Zinga is still often mistaken for a paint simply because
its liquid and comes in a tin. But there are other, more subtle differences. For example it
does not skin over in the tin because Zinga has an unlimited pot-life, it doesnt go
tacky like a paint and also the thickness of a Zinga coat cannot be measured wet
because it flattens off and dries too quickly.

Active Protection
Cathodic protection, or active protection, arises from the zinc (the anode) sacrificing itself
in favour of the base metal (the cathode) with the resulting flow of electrons preventing
corrosions chemical reaction. In this way the protection of the metal is guaranteed, even
when the zinc layer is slightly damaged. Other well established methods of cathodic
protection include hot-dip galvanising (HDG) and zinc thermal spraying both of which
exhibit a constant sacrificial rate of the zinc layer.
Within Zinga though this sacrificial rate reduces dramatically after the zinc layer has
oxidised and the natural porosity have been filled with zinc salts. Additionally each zinc
particle within the Zinga layer is encased and protected by the organic binder without
adversely affecting the electrical conductivity. This enables Zinga to create nearly the same
rate of zinc loss because, put simply, the binder acts as a corrosion inhibitor to the zinc.
Please see the Zinc Loss Prediction Chart further down this page for a estimate of expected
zinc coating service life.
"The zinc in Zinga becomes the sacrificial anode in relation to the steel but it
corrodes at a much slower rate than would otherwise be expected"
(Extract from B.N.F. Fulmer report of JJB Ward, Oxfordshire, Jan '92)

If the Zinga layer is sufficiently damaged to expose the base metal below, the steel would
the surface discolouration was removed the steel below would not be pitted or eroded. This
is called "throw" and enables Zinga to protect bare metal up to 3 - 5mm or so away from
where the coating ends slightly less than new HDG. Zinc sacrificial anodes used on the
surrounding area. Zinga is simply a different form of these anodes and is therefore
The ability of zinc to provide galvanic protection is a function of its weight per given area.
Dry Zinga contains a minimum of 96% pure zinc by weight, the particles of which are
significantly smaller than those found in most coatings. The Zinga particles small size and
elliptical profile ensures maximum contact between both the individual particles and the
substrate. This greater density of zinc per given area combined with the good conductivity
of the binder ensures that charge flows through every millimetre that has been coated and
therefore provides excellent cathodic protection.
Passive Protection
Passive protection, such as paints and cladding, creates a "barrier" between the steel
substrate and the elements. Once this barrier is compromised then the moisture and
corrosion will then begin to creep extensively beneath the coating.
With Zinga, the organic binder and the zinc oxide layer that forms on the surface create an
impervious barrier by blocking the zinc's natural porosity with oxide particles. Unlike other
passive coatings, once breached the zinc oxide layer simply renews itself by re-oxidising.
This layer of oxides is the reason behind the matt appearance of Zinga as opposed to the
shiny hot-dipped finish and is the key to Zinga's extra long life.
Predicted Service Life
The corrosion rates of zinc in various environments have been well researched over the
years. As a result it is possible to chart the predicted service life for a zinc layer at a given
DFT in a particular situation. The chart below is based on Hot-Dip Galvanised steel but, as
it has already been explained in the Active Protection section, Zinga performs at least as
well as HDG in normal atmospheric conditions and even better in marine environments.

You will note on our Standard Specifications that the expected lifespan given is significantly
lower than could be derived from this chart. This is because the Specifications were
established in conjunction with Zingametall's insurers and therefore remain extremely
Duplex Systems
If Zinga is used as part of a duplex system, i.e. is over-coated with another compatible
product, the top-coat provides the initial barrier but the zinc oxide will form a secondary
barrier if the first layer is compromised for any reason. As the top-coat becomes naturally
coat to last longer. It is because of this that Zingametall in Belgium state that the lifetime
of a duplex system can be 50% more than the life of the Zinga and the topcoat combined.
Re-Liquidising of Zinga
Another of Zinga's unique characteristics is its ability to re-liquidise when a new coat of
Zinga is applied to form a single homogenous layer. This ensures a massive cost saving in
on-going maintenance because the old Zinga layer does not have to be removed before recoating with Zinga. This also means that once the initial abrasive blasting has been
completed the surface will never have to be blasted again.

The following microscopic photos demonstrate the total integration of multiple layers of

For further information on the mechanism of Zinga's corrosion protection, please contact
the Zinga UK Technical department.
For sales enquiry contact at:-

Polycoates Engineering Services

305-Cascade Complex, Nr.Chhani Jakat Naka,
Vadodara 390008. India.
Phone 0265 6594294 / 3014966
Tele-fax 0265 3014966
Cell 098242 50796