6 Things You Need to Know About Platinized Titanium Anodes (2)

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Platinum is preferred on an anode's outer surface because it is highly resistant to corrosion and can ensure current flow in most electrolyte media without forming an insulating layer on itself. Because it doesn't corrode, it doesn't produce corrosion products, so the consumption rate is very low.

Platinum is inert in fused salts and acids, whereas it is dissolved in aqua regia. There is no risk of hydrogen embrittlement. (You can learn about hydrogen embrittlement in the article An Introduction to Hydrogen Embrittlement.) It is one of the few rare metals that perfectly resist chlorides of seawater.

Titanium shows reasonably good resistance to a marine environment (seawater in particular). It does not react with concentrated (80%) solutions of metallic chlorides. However, it is susceptible to attack by hydrofluoric acid (HF)and hot hydrochloric acid (HCl) of higher concentrations. Even hydrogen peroxide and hot nitric acid can attack titanium. Oxidizing agents normally do not attack titanium because they readily form a protective oxide coating. However, non-oxidizing substances such as sulfuric acid (above 5% concentration) and phosphoric acid (above 30%) can attack titanium. From a hydrogen embrittlement point of view, titanium fares better than tantalum as an anode material.

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