Materials Research Letters (Dec 2019)

Synthesis of MAX phases Nb2CuC and Ti2(Al0.1Cu0.9)N by A-site replacement reaction in molten salts

  • Haoming Ding,
  • Youbing Li,
  • Jun Lu,
  • Kan Luo,
  • Ke Chen,
  • Mian Li,
  • Per O. Å. Persson,
  • Lars Hultman,
  • Per Eklund,
  • Shiyu Du,
  • Zhengren Huang,
  • Zhifang Chai,
  • Hongjie Wang,
  • Ping Huang,
  • Qing Huang

DOI
https://doi.org/10.1080/21663831.2019.1672822
Journal volume & issue
Vol. 7, no. 12
pp. 510 – 516

Abstract

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New MAX phases Ti2(AlxCu1−x)N and Nb2CuC were synthesized by A-site replacement by reacting Ti2AlN and Nb2AlC, respectively, with CuCl2 or CuI molten salt. X-ray diffraction, scanning electron microscopy, and atomically resolved scanning transmission electron microscopy showed complete A-site replacement in Nb2AlC, which lead to the formation of Nb2CuC. However, the replacement of Al in Ti2AlN phase was only close to complete at Ti2(Al0.1Cu0.9)N. Density-functional theory calculations corroborated the structural stability of Nb2CuC and Ti2CuN phases. Moreover, the calculated cleavage energy in these Cu-containing MAX phases are weaker than in their Al-containing counterparts.

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