DIFFERENT TYPE OF ZINC DEPOSITS
No one-zinc deposit is best for all applications. That is
why Donham Craft Inc. has chosen to provide our
customers with choices. It would be easy to analyze,
control, and inventory products for one type of zinc
plating electrolyte but we would be shortchanging our
customers. Each electrolyte has itís attribute and
shortcomings (efficiencies, chromate receptivity,
throwing power, cost, environmental impact, cosmetic
appearance, embrittlement, etc.).
Discuss your specific needs to with any one of our
technical staff to best match the best deposit
characteristics for each of your applications. Our goal
is to provide you and your customer with the most
cost-effective deposit for each application. top

ACID CHLORIDE ZINC
Is compatible with most substrates (base metals). Acid
Chloride Zinc is easily plated over most substrates and is
the best method if depositing zinc on malleable,
high-carbon, heat-treated, and carburized substrates.
One of the difficulties with this deposit is its high
efficiency. A plating solution that has a high efficiency
tends to plate the HCD (high current density) areas
faster than the LCD (low current density) area.
It is said to have a 10:1 ratio. top

ALKALINE NONCYANIDE ZINC
Is considered one of the most environmentally friendly
plating solutions. This is true because it was the first
zinc plating solution to mimic the characteristics of
cyanide zinc without the aid of cyanide as a grain refiner.
It is a wonderful deposit on most common steel
substrates. Its best attribute is its throwing power
(ability to cover into recesses of parts) especially on
deep drawn shell work. These LCD (low current density)
areas are generally plated as bright and clear
as the significant surfaces of a part.
This electrolyte is said to have
an HCD to LCD ratio of 3:1. top

CYANIDE ZINC
The most tried and true of all the zinc deposits. While it
is considered a toxic solution because of its various
cyanide concentrations. The industry has been
comfortably treating cyanide for the past 4
decades with few problems. Cyanide is easily treated
with chlorine gas or sodium hypochloride
breaking it down to ts simplest form of nitrogen
and carbon dioxide. Cyanide zinc plated deposit is
very similar to that of alkaline non-cyanide zinc except
its LCD areas are usually not as bright and clear. But its
greatest attribute is its ability to plate heavy deposits
with no concern of the infamous delayed blister that are
more common with today's alkaline non-cyanide zinc's
deposits. Heavy zinc deposits are thickness
greater than .0005 inches. top

MECHANICAL ZINC PLATING
Also known as peen plating or impact plating, had itís
origin some 50 years ago. Zinc deposit of less than .001
inches are considered mechanical plating while deposits
greater than .001 inches up to .0022 inches are what
we call Mechanical Galvanizing. The greatest attribute
of any variety of peen plating is it ability to plate
a high carbon steel or a spring steel with little or no
induced hydrogen, hence no worries of hydrogen
embrittlement and no need for subsequent post plating
bake to drive off any included hydrogen. top

MECHANICAL GALVANIZING
Same as above except for heavier deposits
usually greater than .022 inches.
Please refer to the quick reference chart
for other comparisons. top

CYANIDE COPPER PLATING
Has similar health and environmental concerns as with
other cyanide plating solutions. But once again it
is easily treated in today's modern waste treatment
systems. It would be hard to imagine an existing job
shop plater that does not have some form
of copper plating abilities. top

CYANIDE COPPER STRIKE
Copper is used as a strike to improve adhesion of the
plated deposit to the substrate as well as an
inexpensive barrier coat between brass substrates
and a tin or tin lead deposit. The zinc in the brass likes
to migrate into tin and tin lead deposits used in
the electronic industry. A copper barrier coat of no less
than .000050 inches tends to slow down the
migration of the zinc into the final deposit which
will greatly improve the shelf life of a product, especially
if future solderability is required. It should be noted that
the best barrier coat for shelf life purposes would be
a watts or sulfamate nickel deposit of no less than
.000050 inches. Since nickel has a much tighter
grain structure than copper, it can hold off
the zinc migration 10 times longer
than a copper barrier coat. top

ACID COPPER SULFATE BATH
Are widely used in the area of printed circuits,
electronics, rotogravure, plating on plastics, decorative
copper and electroforming applications. While
the deposit of copper from and acid based electrolyte
is often more efficient, less expensive and easier to
waste treat and other alkaline solutions, it too has
it draw backs. Most importantly, steel parts must be
plated with a cyanide copper or a nickel strike
to prevent immersion copper from forming on
the substrate. This will cause a very poor bond
between the base metal and the acid copper
deposit that will blister or peel causing a reject. top

NICKEL PLATING
Nickel is plated from a number of different electrolytes
(watts, woods, sulfamate, and electroless) and for
a number of different purposes (decorative, engineering
and barrier coats). Each coating has its own unique
properties that can be selected to meet
specific customer requirements. top

DECORATIVE NICKEL
(Watts Bath)
In it simplest form decorative nickel is plated from
a watts bath usually over a polished or bright substrate.
As plated nickel deposited from a watts bath are
yellowish in appearance and it has an ability to level out
small imperfections in the base metal. The amount of
leveling that a nickel bath provides is based on
its organic makeup as well as the overall condition of
the plating solution. In order to meet with a decorative
appearance, the nickel is very often post plated with a
layer of chrome, brass or gold, depending on the
end users requirements. The decorative deposits that
we are most accustomed with are nickel/chrome
that is seen on car bumper and motorcycle parts,
and nickel/gold that is used on
the majority of costume jewelry. top

BRIGHT NICKEL
(Watts Bath)
Bright nickel solutions are similar to decorative nickel
solutions but are considered not as HOT as bright nickel
solutions. This means that they have less organic
additives that tend to make the nickel deposit more
ductile but not as bright as a decorative bath.
These baths are used where parts may be crimped
or bent during the assembly process. top

WOODS NICKEL
(Strike)
Woods nickel deposits are almost always used as
an activator over stainless steel. The nickel deposited
will remain active longer than the stainless steel
allowing time for subsequent deposits to be applied
without concern of adhesion problems.
Woods nickel is used as an activator/nickel strike
over many varieties of stainless steel.
This is because stainless steel is difficult to plate
metal due to the formation of a passive oxide on
the surface of the metal.
Woods nickel baths are comprised of only
two items, nickel chloride and hydrochloric acid
used at a 1:1 ratio. top

SULFAMATE NICKEL
(Engineering and Electroforming)
Nickel sulfamate deposits have little or no stress
even at heavy thickness. This solution is most popular
for electroforming because of its high rate of
deposition and its lack of stress. top

ELECTROLESS NICKEL
(Engineering)
EN baths are unique in that they do not require any
electrical current to deposit nickel metal. These baths
are autocatalytic in nature. Because of this we do not
have to be concerned with high and low current
density areas. When a part is submerged in the
plating solution anywhere that the solution touches
will plate at the same rate. A good rule of thumb
for a mid-phos EN is that it will deposit .0007" in
one hour. Besides the uniformity of the deposit, EN also
has many other characteristics that can be used for
engineering purposes such as ductility, lubricative,
corrosion resistance, wear and abrasion resistance
as well as solderability and hardness.
The characteristics listed above can be altered by
the phosphorous content of deposit. For example
high and low phosphorous deposits have a much higher
corrosion resistance than a mid-phos bath. top

TIN PLATING
Tin and tin/lead are deposited in many forms and from a
number of different electrolytes. There is bright tin,
matte tin, 90/10 tin/lead, 60/40 tin/lead, deposited from
sulfate, fluoborate, methane-sulfonic acid based
solutions. Tin can also be plated from an alkaline
stannate bath. Tin and its alloy are primarily plated for
their solderability and electrical characteristics.
Bright deposits are very smooth and mirror like
in appearance while matte deposits are flat and white
to gray in color. Matte tin deposits have a very low
included carbon content and tend to solder better
than bright deposits which have a much higher
included carbon in the deposit because of the organic
additives that are used to provide a tighter
grain structure. top

SILVER PLATING
Silver is plated predominately from cyanide based
electrolytes. The silver can be plated with little or no
organic additives which produces a very dull to
chalk-white deposit. This dull deposit can be easily
burnished to appear bright on the exposed surfaces.
If a true bright silver deposit is required, then
organic additives can be used to refine the grain of
the deposit producing a full bright appearance. top

GOLD PLATING
Gold plating is used for decorative applications as well
as electronic. The majority of gold plated is for the
electronic components, semiconductors, and printed
circuit applications. Gold, with high electrical conductivity,
low contact resistance and good solderability, is a good
choice for most electronic components. Depending on
the end users requirements, the component
to be gold plated will often have a barrier coat
of copper, nickel, or copper and nickel prior
to the gold deposit. Again depending upon the customer
requirements the gold deposit can be a little as
.000002" to .0001" thick. An average thickness
for most electronic components would be
.000015" to .000030". top