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Properties in Reactive Structure Materials: ZrW 2 and HfW 2 – High Melting Temperatures, Densities, Hardness, and Exothermic Ignition Energies
Author(s) -
Evers Jürgen,
Huber Stefan,
Oehlinger Gilbert,
Klapötke Thomas M.
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000237
Subject(s) - exothermic reaction , ignition system , autoignition temperature , materials science , phase (matter) , thermodynamics , crystallography , chemistry , physics , organic chemistry
ZrW 2 and HfW 2 were prepared by melting the constituent elements in an arc‐furnace. By cooling through perictectic phase lines above approximately 2000 °C, samples of the nominal 1:2 composition were obtained as products consisting of two phases, of which approximately 95 % adopts the MgCu 2 type structure and 5 % the W structure. In ZrW 2 and in HfW 2 , the MgCu 2 type structure enables efficient topological compact spacefilling of the smaller W atoms into the cavities of the three‐dimensional net constructed by the larger tetravalent metals Zr and Hf. Correspondingly, very dense and hard alloys are obtained which burn at a crash in air in a strong exothermic ignition reaction. These materials are non‐toxic.