Engineering
Corner
Zinc
Metalizing
A
process ahead of its time
Zinc
Metallizing is a versatile process which melts
Zinc or ZincAlloy metals, and then rapidly propels
the molten Zinc particles onto a prepared substrate,
creating a lamellar or layered coating. Metallizing,
or Thermal Spraying as it isoften called, is a
highly effective and proven method of corrosion
prevention, giving galvanic as well as barrier
coating protection to iron and steel.
 How
Does It Work?
Pockets
of rust form when a scratch occurs on painted
steel. Corrosion pits and blisters will continue
to grow.
 A
zinc metallized coating sacrifices itself by galvanic
action when scratched. Sacrificial action will
continue as long as any zinc remains in the area.
Most protective coating systems for steel function
solely by acting as a barrier between the steel
and the corrosive environment. If these passive
and permeable barriers are damaged or penetrated,
moisture and oxygen can reach the steel causing
rust and eventual coating failure. Azinc metallized
coating also offers barrier protection; however,
the electrochemical relationship between zinc
and steel allovvs a zinc coating to give cathodic
protection as well. A zinc metallized coating
will protect the steel galvanically: it will corrode
in preference to steel, continuing to protect
as long as any zinc remains in the immediate area.
The surface of a metallized coating permits excellent
adhesion of sealers and topcoats. The effect of
this combination is a synergistic coating system
which will protect the underlying steel and require
little or no maintenance for many years.
THE ADVANTAGES OF ZINC METALIZING
In
A Word . . . Longevity
Proven
Long Term Protection: A sealed, zinc metallized
coating can realistically provide 30 years of
corrosion protection in rural environments and
15 to 25 years in urban and coastal areas. Severe
atmospheric conditions will not rust steel protected
by a zinc metallized coating.
Versatility:
Coating thickness can be varied. This is important
because the protection achieved is directly proportional
to the weight of a zinc metallized coating. Severe
atmospheric conditions and longer life require
an increased coating thickness. The thickness
can also vary on different areas of the same structure,
such as troublesome flange edges, giving needed
extra protection. Applied zinc metallized coatings
will not mudcrack, run or sag when applied over
.006'’ thickness.
No
Drying/Curing Time: A zinc metallized coating
bonds instantly allowing for immediate application
of wash primers and sealers. Because there is
no drying time, additional labor costs, lengthy
setup times and constant maintenance scaffolding
costs are reduced or eliminated.
No
Size Limitation: Whether the job is in your shop
or in the field, there is no limit to the size
of the structure to be coated with Zinc.
No
Warpage: The surface being coated remains at ambient
temperatures. Therefore, a zinc metallized coating
does not distort the shape of the steel, nor will
it affect its metallurgical structure. Weld embrittlement,
overtempering and steel strength losses are not
a concern when metallizing with zinc.
No
VOC's: In today's concerns for the environment,
the coating industry is interested in protecting
the infrastructure without damaging the environment
around it. A zinc metallized coating is inorganic
and does not contain volatile compounds that can
harm the environment.
|
