Details

Autor(en) / Beteiligte

• Feng, Xiaokang
• Bao, Kuo
• Tao, Qiang
• Li, Li
• Shao, Ziji
• Yu, Hongyu
• Xu, Chunhong
• Ma, Shuailing
• Lian, Min
• Zhao, Xingbin
• Ge, Yufei
• Li, Da
• Duan, Defang
• Zhu, Pinwen
• Cui, Tian

Titel

Role of TM–TM Connection Induced by Opposite d‑Electron States on the Hardness of Transition-Metal (TM = Cr, W) Mononitrides

Ist Teil von

• Inorganic chemistry, 2019-11, Vol.58 (22), p.15573-15579

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Recent reports exposed an astonishing factor of high hardness that the connection between transition-metal (TM) atoms could enhance hardness, which is in contrast to the usual understanding that TM–TM will weaken hardness as the source of metallicity. It is surprising that there are two opposite mechanical characteristics in the one TM–TM bond. To uncover the intrinsic reason, we studied two appropriate mononitrides, CrN and WN, with the same light-element (LE) content and valence electron concentration. The two high-quality compounds were synthesized by a new metathesis under high pressure, and the Vickers hardness is 13.0 GPa for CrN and 20.0 GPa for WN. Combined with theoretical calculations, we found that the strong correlation of d electrons in TM–TM could seriously affect hardness. Thus, we make the complementary suggestions of the previous hardness factors that the antibonding d-electron state in TM–TM near the Fermi level should be avoided and a strong d covalent coupling in TM–TM is very beneficial for high hardness. Our results are very important for the further design of high-hardness and multifunctional TM and LE compounds.