Tantalum
Tantalum is also famous for its resistance to corrosion by acids. In fact, below 150°C, tantalum is almost completely immune to corrosion by aqua regia. Due to its resistance to attack by body fluids, tantalum provides excellent material for medical devices. Tantalum has good thermal conductivity and is used to manufacture heating elements, vacuum tubes, and other high-temperature parts. Another significant use of tantalum is for electronic components, and due to its absorption properties, tantalum is an excellent getter of residual gasses in evacuation tubes. Tantalum films provide very high capacitance per volume allowing miniaturization of electronics and circuitry. Tantalum capacitors are used in computers and cellular phones.
Physical Properties of Tantalum
Tantalum Physical Properties |
Density |
lb/in3 |
0.6 |
|
gm/cm3 |
16.6 |
Melting Point |
°F |
5425 |
|
°C |
2996 |
Thermal Conductivity |
Cal/cm2/cm°C/sec |
0.13 |
Specific Heat |
Cal/gm/°C |
0.036 |
Coefficient of Linear Thermal Expansion |
micro-in/°F x 10-6 |
6.5 |
|
micro-in/°C x 10-6 |
3.6 |
Electrical Resistivity |
micro-ohm-cm |
12.4 |
Mechanical Properties of Tantalum
Tantalum Mechanical Properties |
Tensile Strength |
KSI (Mpa)-RT |
250 (1725) |
|
KSI (Mpa)-500°C |
150 (1035) |
|
KSI (Mpa)-1000°C |
75 (515) |
Elongation |
% in 1.0". |
-- |
Hardness |
DPH |
300 |
Modulus of Elasticity |
KSI |
58000 |
|
Gpa |
400 |
Tantalum Chemistry |
Minimum % 99.99 |
Chemical Behavior of Tantalum
Tantalum Chemical Behavior |
Water |
Hot water < 150 °C |
resistant |
Inorganic Acids |
Hydrochloric acid < 30 % up to 190 °C |
resistant |
Sulfuric acid < 98 % up to 190 °C |
resistant |
Nitric acid < 65 % up to 190 °C |
resistant |
Hydrofluoric acid < 60 % |
not resistant |
Phosphoric acid < 85 % up to 150 °C |
resistant |
Organic Acids |
Acetic acid < 100 % up to 150 °C |
resistant |
Oxalic acid < 10 % up to 100 °C |
resistant |
Lactic acid < 85 % up to 150 °C |
resistant |
Tartaric acid < 20 % up to 150 °C |
resistant |
Lyes |
Sodium hydroxide < 5 % up to 100 °C |
resistant |
Potassium hydroxide < 5 % up to 100 °C |
resistant |
Ammonia solutions < 17 % up to 50 °C |
resistant |
Sodium carbonate < 20 % up to 100 °C |
resistant |
Saline Solutions |
Ammonium chloride < 150 °C |
resistant |
Calcium chloride < 150 °C |
resistant |
Ferric chloride < 150 °C |
resistant |
Potassium chlorate < 150 °C |
resistant |
Body fluids < 150 °C |
resistant |
Magnesium sulfate < 150 °C |
resistant |
Sodium nitrate < 150 °C |
resistant |
Tin chloride < 150 °C |
resistant |
Non-metals |
Fluorine |
not resistant |
Chlorine < 150 °C |
resistant |
Bromine < 150 °C |
resistant |
Iodine < 150 °C |
resistant |
Sulfur < 150 °C |
resistant |
Phosphorous < 150 °C |
resistant |
Boron < 1 000 °C |
resistant |
Applications of Tantalum
Capacitors, surgical implants and instruments, ink jet nozzles.