Note: Zirconium metal, also known as sponge zirconium, is a silver gray metal with a steel like appearance and luster; Melting point 1852, secondary point, boiling point 4377, density 6.49. Zirconium is easy to absorb hydrogen, nitrogen and oxygen; Zirconium has a strong affinity for oxygen, and its volume can be significantly increased when oxygen is dissolved in zirconium at 1000 ℃. Zirconium is relatively stable in air; Zirconium powder is easy to burn. Fine zirconium wire can be ignited with a match. It can be directly combined with dissolved oxygen, nitrogen and hydrogen at high temperature. It is mainly used in aerospace, military, nuclear reaction, atomic energy, and addition of metal superhard materials to make bulletproof alloy steel, and can also be used as a coating alloy for uranium fuel in reactors.