Radiation-induced phase separation in nanostructured Hf-In-C ternary thin films under irradiation with 200 keV Ar⁺ ion beam

Abstract

Thin films consisting of 17 groups of Hf/In/C multilayers cyclically alternating layers of Hf, In and C each with a thickness of 4–5 nm were synthesized by ion sputtering using a 25 keV Ar⁺ ion beam with 400 µA current and targets made of pure hafnium, indium and carbon. The films were subsequently annealed in vacuum at 120°C for 24 hours to induce intermixing of elements phases, their interaction, and formation of the Hf-In-C nanostructures (including the Hf₂InC MAX phase). After fabrication, a part of the pristine (as deposited) samples was irradiated by 200 keV Ar⁺ ions at high fluences 10¹⁵ and 10¹⁷ cm⁻². Both samples (as prepared and irradiated) were analyzed by IBA nuclear analytical methods, as well as by AFM and TEM microscopic techniques, and by XPS and profilometry to understand the microstructural evolution. Moreover, nanoindentation analysis was performed to assess the effects of ion irradiation on the microstructure and mechanical properties of the films. The experimental results showed that thin Hf-In-C nanostructured films can be formed by ion sputtering with promising mechanical parameters. The irradiated Hf-In-C films were found to be resistant only up to a fluence of about 10¹⁵ Ar cm⁻². At higher fluences it degrades, and Hf₂InC transforms to the binary HfC_0.95 phase due to sublimation of In. At 10¹⁷ cm⁻² the original matrix (including M₂AX) is destroyed, and instead, a mixture of MX binary phases (e.g. HfC_0.95) and crystalline oxides (e.g. HfO₂ and In₂O₃) are formed.

KEYWORDS:

• Ion beam synthesis
• Hf-In-C nanocomposite
• Hf₂InC MAX phase
• HfC₀.₉₅ phase
• radiation tolerance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research on the paper was supported by the Czech Science Foundation [project number 18-21677S]. The experiments were carried out with the help of large research infrastructures CANAM and CzechNanolab supported by the Ministry of Education, Youth and Sports of the Czech Republic [project numbers LM2015056 and LM2018110], respectively.

Notes on contributors

Jiri Vacik

Dr Jiri Vacik is a specialist in nuclear analytical methods and materials science.

Antonino Cannavò

Dr Antonino Cannavo is a specialist in materials science and engineering of materials using lasers.

Snejana Bakardjieva

Dr Snejana Bakardjieva is a specialist in chemical and materials science and microscopic techniques.

Jaroslav Kupcik

Dr Jaroslav Kupcik is a specialist in materials science and microscopic techniques.

Vasily Lavrentiev

Dr Vasily Lavrentiev is a specialist in synthesis of hybrid materials, ion beam analytical methods and AFM.

Giovanni Ceccio

Dr Giovanni Ceccio is a specialist in materials science and engineering of materials using lasers.

Pavel Horak

Dr Pavel Horak is a specialist in ion beam analysis and thin film deposition.

Jiri Nemecek

Prof. Jiri Nemecek is a specialist in mechanical properties (nanoindentation) of thin films.

Alessio Verna

Dr Alessio Verna is a specialist in electrical properties of materials.

Matteo Parmeggiani

Dr Matteo Parmeggiani is a specialist in surface characterization of thin films.

Lucia Calcagno

Prof. Lucia Calcagno is a specialist in radiation hardness of semiconductors.

Robert Klie

Prof. Robert Klie is a specialist in experimental condensed matter physics and microscopic techniques.

Jan Duchoň

Dr Jan Duchoň is a specialist in specialist in condensed matter physics and microscopic techniques.