Ceramic Alloy Materials
Ceramic materials are inorganic,
non-metallic solids. They may be crystalline or amorphous in nature, and are
prepared by giving appropriate heating and cooling treatment to these materials.
Technically, these can be defined as inorganic oxides, non-oxides or
particulate materials that are generally crystalline in nature. The most
commonly seen ceramic materials are the pottery and bricks that are made from
clay, although they have now found many new uses in engineering, semiconductor
industry, tooling, ballistic, gas turbine engines, watches, dental implants,
synthetic bones and space equipments.
Ceramic Alloy Materials
Ceramics can broadly be
classified into oxides, non-oxides and composites.
Oxide Ceramics
Oxide ceramics – such as alumina
or zirconia – are resistant to oxidation, do not react chemically, are good
electrical and thermal insulators. These are required to be extremely pure and
the manufacturing process is therefore elaborate and complex enough to ensure
that no impurities that can significantly alter the properties of these
ceramics are left behind. Further, heat treatments for these ceramic materials
are attuned to give them a specific crystal structure.
Non-oxide Ceramics
Non-oxide ceramics – like
carbides, borides, nitrides or silicides – are typically more prone to oxidation,
very hard but chemically un-reactive, and also have good thermal and electrical
conductivity properties. Manufacturing non-oxide ceramic materials is generally
a three step process, where the required non-oxides are firstly prepared, then
mixed into a desired powder and finally heat treated in a controlled
oxygen-free environment.
Composites
Composites are a combination of
oxides and non-oxides, which have been reinforced together using some
particulate matter. They are generally tough and are costly to manufacture,
while their conductivity and oxidation resistance will vary on the exact
composition. It is possible to prepare a wide variety of such composite
ceramics (based on what is the combination of oxides, non-oxides, polymers that
are reinforced together), with the objective to tune the toughness, hardness or
conductivity that is appropriate for a required condition or application.
Some Examples of Ceramic
Materials
Ferrite Magnets, classified as ceramics, are inexpensive
permanent magnets. They are however very brittle and should therefore not be
used in structural applications. They also have a relatively low thermal
tolerance and begin to break down around 300C. These are prepared using iron
oxide and strontium or barium oxide, compressed together along with some
ceramic binder.
BAM is a ceramic material that contains boron, aluminum,
magnesium and titanium boride. It is one of the hardest and smoothest known
materials, and finds application in all places that require hard materials that
are wear resistant and need frictionless environments (such as coatings on
moving parts of equipments and machines). It is licensed an Iowa
based company, Des Moines .
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