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Structure and Physicomechanical Properties of Nanostructured (TiHfZrNbVTa)N Coatings after Implantation of High Fluences of N⁺ (10¹⁸ cm¯²)

100%

Pogrebnjak A., Bondar O., Borba S., Piotrowska K., Boiko O.

Acta Physica Polonica A

2017

vol. 132

issue 2

217-221

New classes of high-entropy alloys, which consist of at least 5 main elements with atomic concentrations 5-35 at.%, are under great interest in modern material science. It is also very important to explore the limits of resistance of high-entropy alloy nitrides to implantation by high-energy atoms. Structure and properties of nanostructured multicomponent (TiHfZrNbVTa)N coatings were investigated before and after ion implantation. We used the Rutherford backscattering, scanning electron microscopy with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy and scanning transmission electron microscopy with local microanalysis, X-ray diffraction and nanoindentation for investigations. Due to the high-fluence ion implantation (N⁺, the fluence was 10¹⁸ cm¯²) a multiphase structure was formed in the surface layer of the coating. This structure consisted of amorphous, nanocrystalline and initial nanostructured phases with small sizes of nanograins. Two phases were formed in the depth of the coating: fcc and hcp (with a small volume fraction). Nitrogen concentration reached 90 at.% near the surface and decreased with the depth. Nanohardness of the as-deposited coatings varied from 27 to 34 GPa depending on the deposition conditions. However, hardness decreased to a value of 12 GPa of the depth of the projected range after ion implantation and increased to 23 GPa for deeper layers.

Discrete angle rotations of Bi nanoparticles embedded in a Ga matrix

64%

Be’er A., Kofman R., Lereah Y.

Open Physics

2010

vol. 8

issue 1

1-6

Spontaneous instabilities of nanoparticles are known to be influenced by the temperature, and strongly depend on the particle size. However, it is not clear what is the role of the surrounding material that is in contact with the particle. Here we report on the difference between spontaneous rotations of Bi nanoparticles embedded in amorphous SiO and those embedded in liquid Ga. The phenomenon was studied quantitatively by time resolved transmission electron microscopy using Fourier Transform analysis of highresolution electron microscopy images. While rotations of Bi nanoparticles embedded in amorphous SiO occur by all angles, the rotations of Bi nanoparticles embedded in liquid Ga occur by discrete angles. Our results point quantitatively, for the first time, to the role and importance of the contacting surrounding surface during the rotation of nanoparticles.

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1 Acta Physica Polonica A

1 Open Physics

1 2017

1 2010

1 Be’er A.

1 Boiko O.

1 Bondar O.

1 Borba S.

1 Kofman R.

1 Lereah Y.

1 Piotrowska K.

1 Pogrebnjak A.

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Structure and Physicomechanical Properties of Nanostructured (TiHfZrNbVTa)N Coatings after Implantation of High Fluences of N⁺ (10¹⁸ cm¯²)

Discrete angle rotations of Bi nanoparticles embedded in a Ga matrix