Tantalum excellent chemical properties, high corrosion resistance. In both cold and hot conditions, the hydrochloric acid, nitric acid and aqua regia "reaction. 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 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, to corrode the thickness of 0.116 mm a year, at 300 degrees, the corrosion Speed is more faster, soak 1 year, the surface corrosion of 1.368 mm. In fuming sulfuric acid corrosion of SO3 (including 15%) than in the sulfuric acid is more serious, in the 130 - degree of the solution for 1 year, the thickness of surface corrosion is 15.6 mm. 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 more fear of alkali tantalum, 40% in 110 - degree concentration of caustic soda solution , tantalum can be quickly dissolved, in the same concentration of potassium hydroxide solution, as long as 100 degrees can be quickly dissolved. In addition to the above, the general inorganic salt corrosion under 150 degrees generally cannot tantalum. Experiments show that tantalum at room temperature, the alkali solution, chlorine, bromine water, dilute sulphuric acid and many other drugs don't work, only under the effect of hydrofluoric acid and hot concentrated sulfuric acid. The situation in the metal is relatively rare.
But under high temperature, tantalum oxide film on the surface of the damaged, so it can react with a variety of material, temperature tantalum can react with fluoride. At 150 degrees, tantalum of chlorine in bromine iodine is inert, in 250 degrees, tantalum for dry chlorine corrosion resistant ability, still in the chlorine containing water vapor heated to 400 degrees, can still keep shining, in 500 began to corrode, above 300 degrees tantalum reaction with bromine, the iodine steam is when the temperature reaches are in inertia. The red before hydrogen chloride in 410 degrees and tantalum reaction, five chloride production, hydrogen bromide in 375 degrees and tantalum reaction. When heated to 200 degrees or lower temperatures, S Can interact with Ta, carbon and hydrocarbon in 800-1100 degrees with tantalum.
