Listing description
Zirconium
carbide (ZrC) is an extremely hard refractory ceramic material,[7] commercially used in tool bits for cutting tools. It is usually processed by sintering.
Detailed description
Properties
|
T
|
αV
|
|
100 °C
|
0.141
|
|
200 °C
|
0.326
|
|
400 °C
|
0.711
|
|
800 °C
|
1.509
|
|
1200 °C
|
2.344
|
It has the appearance of a gray metallic powder with cubic crystal
structure. It is highly corrosion resistant. This Group IV interstitial
transition-metal carbide is also a member of ultra high temperature ceramics or (UHTC). Due to the presence of metallic
bonding, ZrC has a thermal conductivity of 20.5 W/m·K and an electrical
conductivity (resistivity ~43 μΩ·cm), both of which are similar to that
for zirconium metal. The strong covalent Zr-C bond gives this material a very
high melting point (~3530 °C), high modulus (~440 GPa) and hardness (25 GPa). ZrC has a lower density (6.73 g/cm3) compared to
other carbides like WC (15.8 g/cm3), TaC (14.5 g/cm3)
or HfC (12.67 g/cm3).
ZrC seems suitable for use in re-entry
vehicles, rocket/SCRAM jet engines or supersonic vehicles in which low densities and high temperatures load-bearing capabilities are crucial requirements.
Like most carbides of refractory metals, zirconium carbide is
sub-stoichiometric, i.e., it contains carbon vacancies. At carbon contents
higher than approximately ZrC0.98 the
material contains free carbon.[5] ZrC is stable for a carbon-to-metal ratio
ranging from 0.65 to 0.98.
The group IVA metal carbides, TiC, ZrC, and SiC are
practically inert toward attack by strong aqueous acids (HCl) and strong
aqueous bases (NaOH) even at 100' C, however, ZrC does react with HF.
Uses
Hafnium-free zirconium carbide and niobium
carbide can be
used as refractory coatings in nuclear
reactors. Because of a low neutron absorption cross-section and weak
damage sensitivity under irradiation, it finds use as the coating of uranium
dioxide and thorium
dioxide particles
of nuclear
fuel. The coating is usually deposited by thermal chemical vapor deposition in a fluidized bed reactor. It also has high emissivity
and high current capacity at elevated temperatures rendering it as a promising
material for use in thermo-photovoltaic radiators and field emitter tips and
arrays.
Production
Zirconium carbide is made by carbo-thermal reduction of zirconia
by graphite. Densified ZrC is made by sintering powder of ZrC at upwards of
2000 °C. Hot pressing of ZrC can bring down the sintering temperature
consequently helps in producing fine grained fully densified ZrC. Spark plasma
sintering also has been used to produce fully densified ZrC.
Poor oxidation resistance over 800 °C limits the
applications of ZrC. One way to improve the oxidation resistance of ZrC is to
make composites. Important composites proposed are ZrC-ZrB2 and ZrC-ZrB2-SiC composite.
These composites can work up to 1800 °C.
PRICE
$9736.6/KG
OR $4425.72/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
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