Chemical nickel plating is used
to deposit nickel without using an electric current. The coating is deposited
by autocatalytic chemical reduction of nickel ions by hypophosphite compounds,
aminoborane or borohydride. Two other methods have been used commercially for
electroplating nickel, without power, including immersion plating (1) on steel
from solutions of nickel chloride and boric acid at 70 ° C (160 ° F) and (2)
the decomposition of nickel carbonyl vapor at 180 ° C (360 ° F). Immersion
deposits, however, are poorly adherent and non protective, whereas the
decomposition of nickel carbonyl is both expensive and dangerous. Therefore,
electroless nickel only gained wide acceptance. Since the commercial use
acquired in 1950, the electroless nickel grown rapidly and is now an
established industrial process.
Currently, low acid hypophosphite
hot bath are the most commonly used for steel plate and other metals, while the
alkaline hot water baths hypophosphite are used for coating metal and plastic.
Borohydride reduced baths are also used to plate iron and copper alloys,
especially in Europe. Nickel is a chemical engineering coating, normally used
due to the corrosion resistance and excellent wear. Electroless nickel coatings
are frequently applied to aluminum to provide a surface for welding and are
used with molds and dies to improve the lubricity and release of some. Because
of these properties, chemical nickel coatings have found many applications,
including oil, chemicals, plastics, optics, printing, mining, aerospace,
nuclear and automotive electronics, computers, textiles, paper, machinery and
foodstuffs (Ref).
Unlike electroplating, electro
less plating allows for storage of materials of uniform coating on all
surfaces, conductivity, size, shape and electrical. Electro-less copper and
nickel phosphorus deposits to provide protective and functional coatings
industries as diverse as electronics, automotive, aerospace and chemical
engineering. This book covers the latest research on the electro deposition of
less.
After an introductory chapter,
the first part focuses on evidence from the review of the chemical copper
areas, such as surface morphology and residual stresses, modeling the surface
structure, the bond strength of the deposition electrolytic copper, the
electrical resistivity and chemical applications of copper deposition. The
second part is going to nickel-phosphorus electroless deposition with chapters
on the crystallization of nickel-phosphorus deposits, the modeling of the
thermodynamics and kinetics of the crystallization of nickel-phosphorus
deposits, artificial neural networks (RNA) models of crystallization
temperatures, the hardness of the evolution of nickel-phosphorus deposits and
applications of electroless nickel-phosphor plates.
Some of the advantages and
limitations of electroless nickel coatings include corrosion resistance
advantages and even wear and excellent cost Weld ability Weld ability of low
wages which exceed the limits of the chemical characteristics of the fragility
of solder plating due to poor plate contamination with nickel phosphorus
deposits need for nickel copper alloys containing significant amounts of lead,
tin, cadmium and zinc before you can apply electroless nickel plates slower
compared to the electrolytic method.
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