Effect of Specific Corrosive Agents

Tantalum is not attacked by hot or cold deionized, fresh water, or seawater. It is also resistant to mine waters that are often acidic. For equipment exposed to boiler waters or condensates, the alkalinity should be controlled. The pH should be less than nine. No failures have been reported for exposure to steam condensate, and the metal is considered resistant to saturated steam below 250°C (3.98 MPa or 577 psia). It has been reported that at 1127°C, water vapor is decomposed by tantalum with absorption of oxygen and evolution of hydrogen. At 927°C and below, the reaction is negligibly slow. 

Like glass, tantalum is immime to attack by almost all acids under normal conditions, except hydrofluoric. Tantalum is not attacked by such acids as sulfuric, nitric, hydrochloric, aqua regia, perchloric, hypochlorous. 

No data are available in this area test tantalum up to about 260°C 

Tantalum can be readily used in this area of temperature and concentrations 

Corrosion resistance of tantalum in sulfuric acid at various concentrations and temperatures. (From M. Schussler and C. Pokross. 1985. Corrosion Data Survey of Tantalum, 2nd ed., Chicago Fansteel.) 

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