| 释义 |
hafnium Chem.|ˈhæfnɪəm|
[f. Hafnia (f. Da. Havn harbour (see haven n.), orig. name of Copenhagen (Da. København)), mod.L. name of Copenhagen: see -ium.]
A metallic element with a silver lustre usually found associated with zirconium, which it closely resembles chemically, and used in nuclear reactor control rods. Symbol Hf; atomic number 72. Earlier called celtium.
1923Coster & Hevesy in Nature 20 Jan. 79/2 For the new element we propose the name Hafnium (Hafniae = Copenhagen). 1955Sci. Amer. Oct. 35 In its ores zirconium is invariably accompanied by hafnium, which absorbs neutrons all too readily. 1957Bull. Amer. Physical Soc. II. 269/1 Hafnium's thermionic efficiency in terms of grams evaporated per unit electron emission is slightly greater than that of Th metal. 1967W. H. Kohl Handbk. Materials & Techniques for Vacuum Devices xii. 329/2 The high neutron absorption of hafnium, its excellent corrosion resistance in high-temperature water, and its adequate strength at reactor operation temperatures make this metal suited as a control material. |