Corrosion of Metals in Sulfuric Acid

The one property that stands out for tantalum metal is its superb corrosion resistance which is demonstrated on this chart. What you are looking at here is an isocorrosion chart of various metals in sulphuric acid. On the y axis you have temperature in degrees C, on the x axis is the sulphuric acid concentration. Each curve represent where the metal will corrode at a rate of 5 mills per year. Below each curve the corrosion rate will be slower and above each curve the corrosion rates are faster. If we compare Tantalum to the other materials you could see it outperforms them all. For example if we look at a solution of sulfuric acid at 60% concentration and at 150C. We could see that titanium has no chance to survive as this point is well above the its curve. The same is true for all Hastelloy grades. For zirconium the corrosion rate will be about 5 mills per year, which for vavles and fittings would lead to failure quite quickly. For these conditions only tantalum metal could perform adequately. The key point of this chart is to understand that tantalum metal is superior to all other metals at various temperatures and concentrations of sulfuric acid . Whats also important to understand is that while this chart specifically focus on sulphuric acid, the trend is the same for many other acids such as hydrochloric acid, acetic acid, phosphoric acid etc…. This is why tantalum metal is known as the most corrosion resistant metal that is commercially available.

Category:

Science & Technology

Tags:

• Corrosion
• Sulfuric
• Acid
• Titanium
• Zirconium
• Hastelloy
• Nickel
• Niobium
• Tantalum

[CorrosionDoctor]

A very good illustration on how iso-corrsion curves works.