Self-organized columnar Zr0.7Ta0.3B1.5 core/shell-nanostructure thin films

SURFACE & COATINGS TECHNOLOGY

卷:401

Article

Bakhit, Babak¹  Palisaitis, Justinas¹  Persson, Per O. A.¹  Alling, Bjorn²  Rosen, Johanna¹  Hultman, Lars¹  Petrov, Ivan^1,3,4,5  Greene, J. E.^1,3,4,5  Greczynski, Grzegorz¹ 

[1] Linkoping Univ, Thin Film Phys Div, Dept Phys IFM, SE-58183 Linkoping, Sweden

[2] Linkoping Univ, Theoret Phys, Dept Phys IFM, SE-58183 Linkoping, Sweden

[3] Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA

[4] Univ Illinois, Dept Mat Sci, Urbana, IL 61801 USA

[5] Natl Taiwan Univ Sci & Technol, Dept Mat Sci & Engn, Taipei 10607, Taiwan

关键词: Thin films;    Transition-metal (TM) diborides;    Self-organized;    Core/shell nanostructure;    Hardness and toughness;   

DOI  :  10.1016/j.surfcoat.2020.126237

来源: Elsevier

【 摘 要 】

We recently showed that Zr1-xTaxBy thin films have columnar nanostructure in which column boundaries are B-rich for x < 0.2, while Ta-rich for x >= 0.2. Layers with x >= 0.2 exhibit higher hardness and, simultaneously, enhanced toughness. Here, we determine the atomic-scale nanostructure of sputter-deposited columnar Zr0.7Ta0.3B1.5 thin films. The columns, 95 +/- 17 angstrom, are core/shell nanostructures in which 80 +/- 15-angstrom cores are crystalline hexagonal-AlB2-structure Zr-rich stoichiometric Zr1-xTaxB2. The shell structure is a narrow dense, disordered region that is Ta-rich and highly B-deficient. The cores are formed under intense ion mixing via preferential Ta segregation, due to the lower formation enthalpy of TaB2 than ZrB2, in response to the chemical driving force to form a stoichiometric compound. The films with unique combination of nanosized crystalline cores and dense metallic-glass-like shells provide excellent mechanical properties.

【 授权许可】

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