| Element |
Characteristics |
Metallurgical Property |
Tantalum
(Ta) |
(1) Extremely high acid resistance
Acid resistance following that of
platinum
(2) Superb high-temperature strength
(3) Excellent dielectric performance
(4) Strong affinity with oxygen,
nitrogen, etc.(getter ability)
|
Melting point : 2,996 °C
Specific gravity : 16.6
Crystal type : Body-centered cubic
lattice
Young's modulus : 18,200 kgf/mm2
|
Niobium
(Nb) |
(1) Acid resistance following that of
tantalum
(2) Superb high-temperature strength
(3) Strong affinity with oxygen,
nitrogen and others(getter
ability)
|
Melting point :
2,468 °C
Specific gravity : 8.4
Crystal type : Body-centered cubic
lattice
Young's modulus : 10,700 kgf/mm2
|
Zir conium
(Zr) |
(1) High corrosion resistance, in
particular highly resistant to acid
and alkali
(2) High flammability
(3) Small cross section for neutron
absorption
|
Melting point : 1,852 °C
Specific gravity : 6.5
Crystal type : Close-packed hexagonal
lattice
Young's modulus : 10,100 kgf/mm2
|
Molybdenum
(Mo) |
(1) Extremely high heat
resistance;
inferior workability
but inexpensive cost when
compared to those of tantalum
and niobium
(2) High corrosion resistance, and
molten metal(Zn, Al, Na, etc.)
|
Melting point : 2,610 °C
Specific gravity : 10.2
Crystal type : Body-centered cubic
lattice
Young's modulus : 33,100 kgf/mm2
|
Tungsten
(W)
|
(1) Highest melting point and specific
gravity among metals
(2) Superb high-temperature strength |
Melting point : 3,410 °C
Specific gravity : 19.3
Crystal type : Body-centered cubic
lattice
Young's modulus : 41,500 kgf/mm2
|
