Zirconium

About Zirconium Metal (Zr) and Zirconium Alloys

Zirconium (Zr) is a highly corrosion resistant metal that is us used for many products for specialized chemical environments (primarily acetic and hydrochloric acids). Some include pumps, valves, nuclear applications, chemical processing, reactor vessels, heat exchangers and more. The nuclear power industry uses nearly 90% of the zirconium produced each year. Zirconium is also used as an alloying agent in steel, to make some types of surgical equipment and as a getter, a material that combines with and removes trace gases form vacuum tubes. Zirconium metal is weldable and formable.

Zirconium 702 offers excellent corrosion protection with resistance to stress-corrosion cracking and crevice corrosion. It’s often used for chemical processing. Alloyed with 2 to 3 percent Columbium, zirconium 705 is significantly stronger and more ductile than zirconium 702 with almost equal corrosion resistance, making it the alloy of choice for most zirconium fasteners. In addition to resisting HCl at all concentrations and at temperatures above the boiling temperature, zirconium and its alloys also have excellent resistance in sulfuric acid at temperatures above boiling and concentrations to 70%. Corrosion rate in nitric acid is less than 1 mil/year at temperatures above boiling and concentrations to 90%. The metals also resist most organics such as acetic acid and acetic anhydride as well as citric, lactic, tartaric, oxalic, tannic, and chlorinated organic acids. Relatively few metals besides zirconium can be used in chemical processes requiring alternate contact with strong acids and alkalis. However, zirconium has no resistance to hydrofluoric acid and is rapidly attacked, even at very low concentrations. There are 4 kinds of corrosion resistant alloyed zirconium in chemical industry: Zr702, Zr704, Zr705 and Zr706, applying to different chemical medium and condition. These four zirconium alloy’s corrosion resistance is almost the same, but their mechanical properties are very different. Zr705’s tensile strength is the twice of Zr702. Usually Zr705 is used in chemical equipment which has a higher requirements for intensity. But in sulfuric acid containing FeCl3, Zr702 and Zr704’s corrosion resistant properties are better than Zr705 and Zr706. Zr706 has enough strength and high elongation and usually used in making heat exchanger.

Zirconium is also highly resistant to heat and corrosion, and it also forms many useful compounds and alloys. These strengths make it an ideal component for nuclear reactions, and it is also used in laboratory equipment, metallurgy and surgical appliances. Jet engines and gas turbines may also use zirconium and zirconium alloys to prevent metals from warping due to high heat exposure. Zirconium (atomic symbol: Zr, atomic number: 40) is a Block D, Group 4, Period 5 element with an atomic weight of 91.224. Zirconium Bohr ModelThe number of electrons in each of Zirconium’s shells is 2, 8, 18, 10, 2 and its electron configuration is [Kr] 4d2 5s2. The zirconium atom has a radius of 160 pm and a Van der Waals radius of 186 pm. Zirconium was discovered by Martin Heinrich Klaproth in 1789 and first isolated by Jöns Jakob Berzelius in 1824. In its elemental form, zirconium has a silvery white appearance that is similar to titanium.

Zirconium’s principal mineral is zircon (zirconium silicate). Elemental Zirconium is commercially produced as a byproduct of titanium and tin mining and has many applications as a opacifier and a refractory material. It is not found in nature as a free element. The name of zirconium comes from the mineral zircon, the most important source of zirconium, and from the Persian wordzargun, meaning gold-like.