Hydrochloric acid is one of the most difficult corrosives for passive alloys to handle. They are
susceptible to serious corrosion problems, including high corrosion rate, localized corrosion and
hydrogen embrittlement. Stainless steels tolerate very low concentrations of chlorides. Nickel-based
alloys may tolerate high concentrations of chlorides, but the temperature cannot be high. Even with the
presence of oxidizing impurities, titanium is not compatible with strong acids. Tantalum is impressive
with respect to its resistance to hot, strong acids. It is, however, susceptible to hydrogen embrittlement.