Defect-induced properties of MoSi2/Nb(Ta)Si2 disilicide nanocomposites

VŠIANSKÁ, Monika, Jana PAVLŮ and Mojmír ŠOB. Defect-induced properties of MoSi2/Nb(Ta)Si2 disilicide nanocomposites. Materials Today Communications. AMSTERDAM: Elsevier Science, 2024, vol. 39, JUN, p. 108584-108596. ISSN 2352-4928. Available from: https://dx.doi.org/10.1016/j.mtcomm.2024.108584.

Basic information

• Original name: Defect-induced properties of MoSi2/Nb(Ta)Si2 disilicide nanocomposites
• Authors: VŠIANSKÁ, Monika (203 Czech Republic, belonging to the institution), Jana PAVLŮ (203 Czech Republic, belonging to the institution) and Mojmír ŠOB (203 Czech Republic, guarantor, belonging to the institution).
• Edition: Materials Today Communications, AMSTERDAM, Elsevier Science, 2024, 2352-4928.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10403 Physical chemistry
• Country of publisher: Netherlands
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 3.800 in 2022
• Organization unit: Faculty of Science
• Doi: http://dx.doi.org/10.1016/j.mtcomm.2024.108584
• UT WoS: 001215649600001
• Keywords in English: Disilicides; C11(b) MoSi2; C40 NbSi2; C40 TaSi2; Nanocomposites; Interfaces; Vacancies; Si and Al impurities; Segregation energies
• Tags: rivok
• Tags: International impact, Reviewed

Abstract

Research on disilicide nanocomposites, as modern materials with promising technological applications, is very desirable these days. Our ab initio analysis concentrates on the C11(b) (tetragonal) MoSi2/C40 (hexagonal) NbSi2 or TaSi2 nanocomposites containing 12 types of interfaces formed by (110) planes in the C11(b) and (0001) planes in the C40 disilicide. The most stable nanocomposites are MoSi2(AC)/Nb(Ta)Si-2(BAC), MoSi2(AB)/Nb(Ta)Si-2(CAB) and MoSi2(AB)/Nb(Ta)Si-2(ABC). The interfaces reveal positive formation energies, e.g. gamma(BA)(IF) = 0.63670 J.m(-2) and gamma(CA)(IF) = 0.63727 J.m(-2) in the Nb system and gamma(BA)(IF) = 0.57837 J.m(-2) and gamma(CA)(IF) = 0.57802 J.m(-2) in the Ta system. In the most stable C(11)b-MoSi2(AC)/C40-Nb(Ta)Si-2(BAC) nanocomposite, the effect of the impurities (Al, Si), vacancies or their aggregates on the stability and structure is investigated. It turns out that (i) vacancies preferentially form at the Si positions in the third (first) layer of MoSi2 in the Nb (Ta) systems, utilising an energy of 2.259 eV.Va(-1) (1.971 eV. Va(-1)); (ii) Al impurities prefer Si positions, and it is easier to introduce them into the Ta system than into the Nb one; however, this does not apply if Al is in the Mo position; (iii) Si impurities prefer Ta positions to Nb ones, and the bulk to interfacial ones; (iv) the Si-Si divacancy is the least destabilising among divacancies; and (v) Al impurities in both systems prevent the formation of Si vacancies, and the Si impurities simplify the formation of vacancies in the Nb system. As there is very little experimental information on the structure and properties of these interfaces, most of the present results are theoretical predictions which may motivate future experimental work.

Links

• LQ1601, research and development project: Name: CEITEC 2020 (Acronym: CEITEC2020)

Investor: Ministry of Education, Youth and Sports of the CR

• 90254, large research infrastructures: Name: e-INFRA CZ II