Brazil is the leading producer of niobium and ferroniobium, an alloy of niobium and iron which has a niobium content of 60-70%. Niobium is used mostly in alloys, the largest part in special steel such as that used in gas pipelines. Although these alloys contain a maximum of 0.1%, the small percentage of niobium enhances the strength of the steel. The temperature stability of niobium-containing superalloys is important for its use in jet and rocket engines.