Views: 0 Author: Site Editor Publish Time: 2022-05-11 Origin: Site
Tantalum has a series of excellent properties such as high melting point, low vapor pressure, good cold workability, high chemical stability, strong resistance to liquid metal corrosion, and large dielectric constant of the surface oxide film. Therefore, tantalum has important applications in high-tech fields such as electronics, metallurgy, steel, chemical industry, cemented carbide, atomic energy, superconducting technology, automotive electronics, aerospace, medical care and scientific research.
50%-70% of the world's tantalum is used to make tantalum capacitors in the form of capacitor-grade tantalum powder and tantalum wire. Since the surface of tantalum can form a dense and stable amorphous oxide film with high dielectric strength, it is easy to accurately and conveniently control the anodic oxidation process of capacitors. Capacitors have high capacitance, low leakage current, low equivalent series resistance, good high and low temperature characteristics, long service life, excellent comprehensive performance, and other capacitors are difficult to compare with. It is widely used in communications (switches, mobile phones, pagers, Fax machines, etc.), computers, automobiles, household and office appliances, instrumentation, aerospace, defense and military industries and other industrial and scientific and technological sectors. Therefore, tantalum is an extremely versatile functional material.
It can be drawn into filaments to make thin foils. Its thermal expansion coefficient is small. Tantalum has very good chemical properties and is extremely resistant to corrosion. It can be used to manufacture evaporating vessels, etc., and can also be used as electrodes, rectifiers, and electrolytic capacitors for electronic tubes.
Medically, it is used to make tantalum flakes or tantalum thin threads to repair damaged tissue.
Although tantalum has strong corrosion resistance, its corrosion resistance is due to the formation of a stable tantalum pentoxide protective film on the surface.
Tantalum has excellent chemical properties and high corrosion resistance. It does not react to hydrochloric acid, concentrated nitric acid and "aqua regia" under both cold and hot conditions. However, tantalum can be corroded in hot concentrated sulfuric acid. Below 150°C, tantalum will not be corroded by concentrated sulfuric acid, and it will react only when the temperature is higher than this.
In 175 degree concentrated sulfuric acid for 1 year, the corroded thickness is 0.0004 mm, and tantalum is soaked in 200 ° C sulfuric acid for one year, and the surface layer is only damaged by 0.006 mm. At 250 degrees, the corrosion rate increased to a thickness of 0.116 mm corroded per year.
At 300 degrees, the corrosion rate is even faster. After 1 year of immersion, the surface is corroded by 1.368 mm. The corrosion rate of oleum is more serious than that of concentrated sulfuric acid. After soaking in the solution at 130 degrees for one year, the thickness of the surface corroded is 15.6 mm.
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