Chemical Properties of Tantalum

Chemical Properties of Tantalum

Tantalum also has excellent chemical properties and has extremely high corrosion resistance. It does not react to hydrochloric acid, concentrated nitric acid and "aqua regia" no matter under cold or hot conditions.

However, tantalum can be corroded in hot concentrated sulfuric acid. Below 150°C, tantalum will not be corroded by concentrated acid. It will only react at temperatures higher than this. Tantalum will be corroded in concentrated sulfuric acid at 175 degrees for one year. The thickness is 0.0004 meters. If tantalum is soaked in sulfuric acid at 200°C for one year, the surface layer will only be damaged by 0.006 mm. At 250 degrees, the corrosion rate increases, and the thickness corroded per year is 0.116 mm. At 300 degrees, , the corrosion rate is even faster. After one year of immersion, the surface is corroded by 1.368 mm.

The corrosion rate in fuming sulfuric acid (containing 15% S03) is more serious than that in concentrated sulfuric acid. After being soaked in this solution at 130 degrees for one year, the thickness of the surface corroded is 15.6 mm. Tantalum will also be corroded by phosphoric acid at high temperatures, but this reaction generally occurs above 150 degrees. After soaking in 85% phosphoric acid at 250 degrees for one year, the surface will be corroded by 20 mm. In addition, tantalum will be corroded by hydrofluoric acid and nitric acid. It can be quickly dissolved in mixed acid and can also be dissolved in hydrofluoric acid.

But tantalum is more afraid of strong alkali. In a caustic soda solution with a concentration of 110 degrees and a concentration of 40%, tantalum will be quickly dissolved. In a potassium hydroxide solution of the same concentration, it will be quickly dissolved at 100 degrees. Except for the above situation, general inorganic salts generally cannot corrode tantalum below 150 degrees.

Experiments have shown that tantalum has no effect on alkali solutions, chlorine gas, bromine water, dilute sulfuric acid and many other chemicals at normal temperature. It only reacts under the action of hydrofluoric acid and hot concentrated sulfuric acid. Such situations are relatively rare in metals.