Zr(Atomic Number : 40)

1. Introduce

– A metal that belongs to a group of four on the periodic table called the titanium group, along with titanium and hafnium

– The metal itself is relatively reactive, but a protective film of zirconium dioxide is formed in air, making it highly corrosion resistant

– In nature, it is always accompanied by hafnium(Hf)

– Zr alloying element effects : improved heat resistance, corrosion resistance

* Zr and Hf

– Zr is always accompanied by Hf in nature

– Zr has nearly the same electron and ionic radii as Hf, and other properties such as density, transition temperature, and chemical properties, except for neutron absorption, are nearly identical

– Zr ores typically have 1 to 4 percent of the Zr added as Hf, so commercially available Zr also typically contains 1 to 4 percent Hf

– Zr absorbs very few neutrons, while Hf is a neutron capture agent that absorbs neutrons 600 times better than Zr, so Hf must be removed from the Zr used in reactors
(Zr Hf separation methods)

– (Europe) : Fractional distillation of tetrachloride compounds (extractive distillation)

– (USA) : liquid-liquid extraction method : utilizes the difference in partitioning of thiocyanate-oxides between water and methyl isobutyl ketone solvent

– (Other) : Fractional determination method : utilizes the difference in solubility of K₂ZrF6₆ and K₂HfF₆ in water

2. Property

– Acid and base corrosion resistance, high temperature corrosion resistance, corrosion resistance, ductility, heat resistance, corrosion resistance, strength, machinability, biocompatibility

[Zr Mechanical Properties]

[Zr Physical Properties]

3. Application

– Nuclear reactors, space shuttles, nuclear fuel cladding, imitation teeth, spacecraft combustion chambers, wings, engines, heavy water reactor pressure pipes, bicycle frames, light filaments, artificial hips, surgical instruments

(1) Space Shuttle / (2) Spacecraft wing / (3) Light filament / (4) Artificial hip joint