Microstructure and materials properties of understoichiometric TiBx thin films grown by HiPIMS

SURFACE & COATINGS TECHNOLOGY

卷:404

Article

Thornberg, Jimmy¹  Palisaitis, Justinas¹  Hellgren, Niklas²  Klimashin, Fedor F.¹  Ghafoor, Naureen¹  Zhirkov, Igor¹  Azina, Clio¹  Battaglia, Jean-Luc³  Kusiak, Andrzej³  Sortica, Maurico A.⁴  Greene, J. E.^1,5,6,7  Hultman, Lars¹  Petrov, Ivan^1,5,6,7  Persson, Per O. A.¹  Rosen, Johanna¹ 

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

[2] Messiah Univ, Dept Comp Math & Phys, Mechanicsburg, PA 17055 USA

[3] Univ Bordeaux, I2M, CNRS, UMR 5295, F-33400 Talence, France

[4] Uppsala Univ, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden

[5] Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA

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

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

关键词: Borides;    Stoichiometry;    Titanium;    Mechanical properties;    Microstructure;    HiPIMS;   

DOI  :  10.1016/j.surfcoat.2020.126537

来源: Elsevier

【 摘 要 】

TiBx thin films with a B content of 1.43 <= x <= 2.70 were synthesized using high-power impulse magnetron sputtering (HiPIMS) and direct-current magnetron sputtering (DCMS). HiPIMS allows compositions ranging from understoichiometric to overstoichiometric dense TiBx thin films with a B/Ti ratio between 1.43 and 2.06, while DCMS yields overstoichiometric TiBx films with a B/Ti ratio ranging from 2.20 to 2.70. Excess B in overstoichiometric TiBx thin films from DCMS results in a hardness up to 37.7 +/- 0.8 GPa, attributed to the formation of an amorphous B-rich tissue phase interlacing stoichiometric TiB2 columnar structures. We furthermore show that understoichiometric TiB1.43 thin films synthesized by HiPIMS, where the deficiency of B is found to be accommodated by Ti-rich planar defects, exhibit a superior hardness of 43.9 +/- 0.9 GPa. The apparent fracture toughness and thermal conductivity of understoichiometric TiB1.43 HiPIMS films are 4.2 +/- 0.1 MPa root m and 2.46 +/- 0.22 W/(m.K), respectively, as compared to corresponding values for overstoichiometric TiB2.70 DCMS film samples of 3.1 +/- 0.1 MPa root m and 4.52 +/- 0.45 W/(mK). This work increases the fundamental understanding of understoichiometric TiBx thin films and their materials properties, and shows that understoichiometric films have properties matching or going beyond those with excess B.

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