Tantalum (Ta): Tantalum forms an extremely stable, protective oxide film making it one of the most corrosion resistant metals known. Below 300° F it is inert to all concentrations of hydrochloric, nitric, sulfuric and phosphoric acids (up to 85%).

Titanium (Ti): Titanium is one of the most resistant materials to the effects of salt water corrosion and is virtually immune to atmospheric corrosion. Titanium can withstand the corrosive effects of metallic salts, chlorides, hydroxides, nitric and chromic acids. Titanium has been proven effective in a number of industries including, chemical, petrochemical and marine industries.

Zirconium (Zr): Zirconium's extremely adherent, stable oxide film gives it the characteristic of excellent chemical resistance to many aggressive chemical reagents. It exhibits good corrosion resistance to alkalis and acids. It resists nitric acid in concentrations up to 95% and temperatures to 400°F. Zirconium fights attack by most alkalis, organic compounds and organic acids. It has excellent resistance to seawater and brackish water.

Niobium (Nb): Niobium, also refereed to as Columbium, is very similar to tantalum. It has the lowest melting point of all the refractory metals covered, the lowest modulus of elasticity and thermal conductivity, and the highest thermal expansion. It also has the lowest strength and lowest density of the refractory metals.