Zircomium is reactive metal that have tensile strength 55,000 - 80,000 psi, density 6.4 g/cc and have best corrosion resistance to organic, mineral acids, alkaline solution and also can use with Sulfuric, Hydrochloric Acid. Ziroconium have stable oxide layer which let them can resist both mechanical and chemical corrosion.

Niobium is reactive metal that have tensile strength 25,000 psi density 8.5 g/cc. Niobium have very thick passive oxide layer so they can resist to very aggressive corrosive acid such as sulfuric acid, hydrochloric acid with very high concentration more than titanium but less than Tantalum. Niobium normally apllied to cathodic-protection anodes because they have good electrical conductivity and have very high break down potential.