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Tantalum Use
Oct 10, 2017

Tantalum, metallic element, mainly exists in tantalite, with niobium symbiosis. The hardness of tantalum is moderate, and it is very malleable. It can be drawn into thin thin foil. Its thermal expansion coefficient is small. Tantalum has excellent chemical properties and is highly resistant to corrosion. No reaction to hydrochloric acid, concentrated nitric acid and "wang shui" in cold and hot conditions. It can be used to make evaporation vessels, and also can be used as electrodes, rectifiers and electrolytic capacitors. A tissue that is used to make laminated or fine lines and repair damage. Although tantalum is resistant to corrosion, its corrosion resistance is due to the stable oxidation of tantalum (Ta2O5) protective film.

Physical properties

Chemical symbol Ta, steel gray metal, is a VB group in the periodic table, atomic number 73, atomic weight 180.9479, body centered cubic crystal, common valence is + 5. The hardness of tantalum is lower, and it is related to the oxygen content, the ordinary pure tantalum, the vickers hardness of the annealing state is only 140HV. Its melting point 2995 ℃, in elemental, second only to carbon, tungsten, and osmium, rounded off the top five in fifth. Tantalum is very malleable and can be made thin thin foil. Its thermal expansion coefficient is small. One centigrade of one degree centigrade expands to six parts per million. In addition, it has a strong toughness and is superior to copper.

Chemical properties

Tantalum also has excellent chemical properties, with extremely high corrosion resistance, no reaction to hydrochloric acid, concentrated nitric acid and "wang shui" in cold and hot conditions. But tantalum corroded in hot concentrated sulfuric acid, and under 150 ℃, tantalum is not concentrated sulfuric acid corrosion, only in the higher temperature will have a reaction, 1 year, in the 175 degrees of sulfuric acid corrosion of thickness is 0.0004 mm, the tantalum in 200 ℃ of sulfuric acid soaking for one year, the surface damage of only 0.006 mm. At 250 degrees, the corrosion rate increased, and the thickness of the corrosion was 0.116 mm per year. At 300 degrees, the rate of corrosion was accelerated, and the surface was corroded 1.368 mm. The corrosion rate of sulfuric acid (15% of SO3) is more serious than that of concentrated sulfuric acid. In this solution of 130 degrees, it is soaked for 1 year and the surface is corroded by the thickness of 15.6mm. Tantalum will also be phosphoric acid corrosion at high temperature, but the reaction occurred in 150 degrees of above commonly, in 85% of the 250 degrees of phosphoric acid, soak 1 year, surface corrosion of 20 mm, in addition, tantalum can quickly dissolved in hydrofluoric acid and mixed acid of nitric acid, can be dissolved in hydrofluoric acid. But tantalum is more afraid of a strong base, and in a caustic solution of about 40 percent of the concentration, tantalum is quickly dissolved, in the same concentration of potassium hydroxide solution, as long as 100 degrees is dissolved quickly. In addition to the above situation, general inorganic salt is generally not corrosive to tantalum under 150 degrees. It is proved that tantalum is not effective for alkali solution, chlorine gas, bromide, dilute sulfuric acid and many other agents at normal temperature, but only reacts under the action of hydrofluoric acid and hot concentrated sulfuric acid. Such situations are rare in metals.

use

The characteristics of tantalum make its application field very wide. Tantalum can be used as an alternative to stainless steel in all kinds of inorganic acid equipment, and it can be several dozens times longer than stainless steel. In addition, in industries such as chemicals, electronics, and electricity, tantalum can replace the tasks needed to be undertaken by precious metal platinum in the past, making the cost of the metal greatly reduced. Tantalum is made into capacitance equipment to military equipment. The U.S. military industry is exceptionally developed and is the world's largest arms exporter. Half of the world's production of tantalum is used in tantalum capacitors, and the pentagon's logistics department, the largest owner of tantalum metal, once bought a third of the world's tantalum powder.





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