In 1751, the nickel (Ni) was discovered in
Stockholm, Sweden by A.F Cronstedt and added to the periodic table. Nickel is a
silver whitish metal that is found on sulfide and arsenic ores. It is derived
by roasting to NiO and reducing the carbon elements. Carbonyl process is used
to manufacture pure nickel grade. On the other hand, the impure nickel grade
reacts with carbon monoxide to form Ni (CO) 4. This is subsequently decomposed
at 200 deg C to succumb nickel alloy.
The pure nickel grade has resistance to
corrosion in water or air. Thus, it is used as a protective coating. The nickel
grade is malleable, ductile and readily soluble in dilute acids, however, the
alkalis will not affect it.
The nickel grades are widely used, ranging
from industrial to engineering applications. Mainly, the nickel grade is used
as a constituent of different types of alloys. Additionally, these are utilized
as a protective coating in the food and chemical processing industries. It is
known as a carcinogen. Nickel is also an allergen to certain individuals.
However, it is a part of many dietetic constituents, and hence cannot be
removed easily.
The
brief description of nickel alloy:
It is a commercially pure (CP) grade having
the properties that are ideal for several fields, mainly in chemical processing
and electronics applications. It has great resistance to many reducing
chemicals and is matchless resistance to caustic alkalies. The commercially
pure nickel has high thermal and electrical conductivity. The nickel alloys
have higher core temperatures and also possess good magnetostrictive
properties. In the annealed condition the nickel grade has a low hardness and
good ductility and malleability. These properties are joined with great
readability makes it highly fabricable.
Nickel Alloy is divided into 2 grade 200
and 201. Nickel alloy 200 Round Bars has
a relatively low work hardening rate; however, it can be cold worked to achieve
moderately high strength and maintains ductility. The nickel alloys have good
mechanical properties and outstanding resistance to many corrosive
environments. Some other salient features of an alloy are its magnetic
properties, low gas content, low vapor pressure, and more.
The corrosion resistance of nickel alloys
makes it particularly useful for maintaining product purity in the handling of
synthetic fibers, and other demanding media. These are used in the structural
applications where corrosion resistance is the prime issue.
The nickel alloy is considered as the
superalloy due to its features offers to any application. These are easily
alloyed with any types of alloying elements and enhance their properties. The
nickel alloys offer great resistance to pitting and crevice corrosion cracking
in the environments that contain warm chlorides. These can be exposed to
elevated temperatures without any elongation and distortion.
The nickel grade offer service in the
exposure of harsh chemicals such as nitric acids, sulfuric acids, phosphoric
acids, and other harsh acids. Advantageously, these are inherent to the
application in organic and inorganic compounds. In the mild cyclic
environments, nickel alloys offer service while retaining its structure and
offering less erosion. These are well suited for the chromium carbide
precipitation range.
