Surface Finishing
Anodizing (Red, Blue, Gray, Black, Gold, Green, Clear) - an electrochemical process which converts an aluminum
surface to a coating of aluminum oxide. This coating can be transparent,
making it suitable for dyeing a wide variety of colors for decorative
or utilitarian purposes; or dull gray, for protection of hardware,
nuts, bolts, and aircraft parts.
Coloring Anodized Aluminum - accomplished by immersing
previously anodized aluminum in a desired color dye bath, which
closes the microscopic
pores in the colored coating. A wide variety of colors give
this finish broad appeal as a decorative finish for giftware,
jewelry, automotive and appliance trim, and exterior architecture.
Black Chemical Film - a
uniform black corrosion retardant for copper. Coating has
no resistance to abrasion.
Black Oxide - a
uniform coating for ferrous metals; mostly a decorative coating.
Very limited corrosion protection is provided. Black oxide
coatings should be given a supplemental treatment of oil coating
or other protective finish.
Black Passivating - a black oxide coating done on stainless steel.
Black Phosphate - a
porous crystalline coating of zinc produced on ferrous metal surfaces
by the reaction of the surface metal to the phosphate solution.
Bright Dipping - in
this process, the part is immersed in a mixture of acids to
provide a bright surface free of stains. It is possible that smoothing
of the
dipped surface may also result, depending on the type of the
solution used and the initial nature of the surface.
Bright Nickel - a silver-white deposit used generally on industrial
products for corrosion protection, and in the chemical and food
processing industries to prevent iron contamination.
Bright Tin - a white, non-toxic,
solderable, soft deposit useful for its resistance to corrosion
and tarnish. Since tin is non-toxic,
it is used as a coating on sheet steel used to manufacture "tin
cans" as well as on food handling equipment.
Buffing - very little material is removed and the surface is improved using very fine
abrasives.
Cadmium - a
silver-white deposit used to minimize galvanic corrosion on
parts or assemblies consisting of dissimilar metals such as
brass and steel, and for its corrosion protection properties
in certain harsh environments.
Caustic Etching - removal of oxide from aluminum in preparation of
anodizing; cleaning of aluminum.
Chromating (Chemical Film) - chemical
conversion coatings are intended to provide corrosion protection
when left unpainted as well as to improve adhesion of paint
finishes on aluminum and aluminum alloy metals. Colors can
range from iridescent yellow to brown.
Copper - a
reddish deposit used for plating through holes on circuit
boards in the electronics industry, on steel wire used in
making high-strength electric cable, and as a stop off to
prevent case hardening on selected areas of iron and steel
surfaces. All pennies made since 1981 are copper-plated zinc.
Copper is also the first layer in "triple chrome" plating.
Electroless Nickel - provides better corrosion and chemical resistance,
greater hardness, wear resistance and lubricity than electroplated
nickel.
Electropolishing - an electrochemical process - the reverse of electroplating.
Instead of coating or plating, electropolishing removes metal
from the surface, leaving a very smooth, clean, bright finish.
Electropolishing is most often performed on stainless steel,
but can also be performed on aluminum and copper alloys. It provides
a surface that is less porous, allowing for reliable sterilization
in the medical and food industries.
Gold - a yellow deposit heavily relied upon in the electronics industry to provide
long-term, dependable electrical contact, solderability, temperature
resistance and corrosion protection in all kinds of devices including
telephones, pagers, cellular phones, printed circuit boards,
televisions, satellites, rockets. Gold is also a common deposit
on jewelry, pens, and optical products.
Passivate - the use of an acid solution to render the surface
of stainless steel to a "passive" state that enhances its corrosion
resistance.
Pickling - acid treatment to chemical remove scale from metal
surface. A number of acids and acid salts are used, and the operating
temperature depends on the material treated. Pickling can also
be done electrolytically. For stainless steels, cathodic pickling
is carried out. For removal of the last stages of smut from high-carbon
steels, anodic pickling is required.
Rhodium - employed in jewelry and silverware for decorative applications, because
rhodium confers a brilliant and tarnish-resistant finish. It
is used on reflectors because of its high reflectivity (78% with
respect to silver) and tarnish resistance. It is used in electronics
on contacts to provide electrically and chemically stable surfaces
which are resistant to wear.
Salt
Spray Corrosion Testing - is an accelerated corrosion test of the impact of salt spray on various metal
finishes.
Sandblasting - cleaning the surface of a part with non abrasive
blasting media such as glass beads, crushed thermoplastic, walnut
shells, poly pellets, or metal media, or, with abrasive blasting
media such as aluminum oxide, silicon carbide, garnet, or zircon.
Silver - used on tableware and hollowware because of its resistance to foods, as well
as in jewelry. Functional uses include preventing galling or
seizing of metal surfaces under high loads, such as on bearings,
threads on stainless steel bolts, and on titanium compressor
blades. It is also used in the electrical and electronics industries
because of its outstanding conductivity.
Vapor Blasting - "blasting"
a water and abrasive mixture through a blasting gun at a part for
rapid finishing and burr removal on part surfaces.
X-Ray Fluorescent Thickness Testing - test used to take thickness measurements for several
different finish layers on various materials.
Zinc - a bluish-white deposit which serves as an inexpensive decorative and sacrificial
protective coating against atmospheric corrosion of iron and
steel parts. It is commonly used on nuts, bolts, wire goods,
fasteners, stampings, and sheet metal parts.
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