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| Tungsten and molybdenum are metals that perform excellently well
at high temperatures. Both have high melting points and are produced
by powder metallurgy processes. Toho Kinzoku, inheriting a tradition
that made the first tungsten electric lamp filaments in Japan, has
considerable expertise in powder metallurgy. Using the knowhow that
the company has cultivated during many years, in various fields we
supply parts that make the best use of the characteristics of both
metals. |
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Making the most of amazing ultrahigh-temperature
performance |
Tungsten was first isolated in 1783 by the de Elhuyar brothers.
In Swedish the name tungsten means heavy stone. Although the chief
source of the metal is wolframite, (Fe,Mn)WO ,
another tungsten ore, scheelite, CaWO ,
exists abundantly in China. Possessing the
highest
melting point and the lowest vapor pressure, tungsten is one of
the extreme metals. Moreover, it has an exceptionally high density
of
19.3 g/cm and other
unique properties. Characteristics such as high-temperature performance,
the lowest coefficient of thermal expansion
of any of
the pure metals, excellent heat and electrical conductivity, have
made it suitable for a wide range of applications, such as lamp
filaments, electrical discharge electrodes, or for use in semiconductors
and
electrical contacts, as X-ray targets, as heating elements in high-temperature
high-pressure furnaces, or as reflectors and crucibles. |
Making the most of ultrahigh-temperature performance
and workability
Molybdos was what the ancient Greeks called
the metal lead. At the end of 18th century the name was borrowed
for the newly discovered
metallic element, molybdenum. Although widely dispersed on the
Earth, molybdenum does not exist in large amounts. It is obtained
chiefly
as by-product from copper ores as molybdenite, MoS  . Possessing
excellent process and superior high-temperature performance,
a low coefficient
of thermal expansion, excellent heat and electrical conductivity,
molybdenum finds widespread use in applications such as magnetron
and illumination parts, use in semiconductors, as sintering trays,
as heating elements in high-temperature high-pressure furnaces,
or in reflectors and crucibles. |
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