Magnesium carbides Mg2C3 and Mg2C are high pressure compounds that can be obtained from the mixtures of elements at HPHT conditions using large-volume multianvil apparatuses. They decompose – quite easily as compared to other carbides – into elements, that render possible crystal growth of graphite (HT conditions) or diamond (decomposition at HPHT). The goal of this project is to perform such in situ HPHT decomposition controlled by heating velocity that allows obtaining nanoparticles of carbon at the initial stages of carbide decomposition, per se or in presence of disordered BN forms. Proposed Mg-C(-BN) nanocomposites are of interest for improving mechanical properties of the Magnesium with C, as well as the binding of C nanoparticles with Mg. The extremes of hardness and fracture toughness for both types of light strong alloys, as well as improved chemical stability (e.g. melting of C-rich Mg instead of burning) are expected.

Metal silicide intermetallic compounds are promising electrocatalysts for the Oxygen Evolution Reaction (OER) due to their exceptional oxidation resistance. While nickel silicides synthesized at ambient pressure have demonstrated remarkable catalytic performance, this study aims to leverage the structural diversity of these materials under high-pressure (HP) conditions to develop novel HP metal silicides with potential applications in electrocatalysis. Focusing on the Ni-Si system, we will employ in situ X-ray diffraction (XRD) with a multi-anvil press (up to 15 GPa) to monitor synthesis in real time. The main objectives are to (1) synthesize CsCl-type NiSi structures, (2) investigate the impact of particle size on phase transformations, and (3) explore the high-pressure phase transitions of Ni₂Si (up to 15 GPa), which remain uncharted in the literature.

Metal silicide intermetallic compounds are promising electrocatalysts for the Oxygen Evolution Reaction (OER) due to their exceptional oxidation resistance. While nickel silicides synthesized at ambient pressure have demonstrated remarkable catalytic performance, this study aims to leverage the structural diversity of these materials under high-pressure (HP) conditions to develop novel HP metal silicides with potential applications in electrocatalysis. Focusing on the Ni-Si system, we will employ in situ X-ray diffraction (XRD) with a multi-anvil press (up to 15 GPa) to monitor synthesis in real time. The main objectives are to (1) synthesize CsCl-type NiSi structures, (2) investigate the impact of particle size on phase transformations, and (3) explore the high-pressure phase transitions of Ni₂Si (up to 15 GPa), which remain uncharted in the literature.

Recent advancements in high pressure (HP) techniques, combined with the development of 4thgeneration sources, have opened up access to a new chemistry of elements. This is evidenced by the significant increase in the number of new compounds synthesized in the megabar range over the last decade. Of particular interest are the new nitride and hydride compounds synthesized at high temperatures (T) and in the range of 50-250 GPa using the laser-heated diamond anvil cell (DAC) [1-6]. This project aims to significantly lower the synthesis pressure and obtain samples of new nitrides, hydrides, and hydronitrides by exploiting the strong reactivity of NH3 as a source of N and H.

Boron carbide (B4C) is a superhard ceramic with applications in various industrial fields, including engineering tools, the nuclear industry, safety armors, and more. However, it exhibits a gradual loss of strength beyond its Hugoniot elastic limit, attributed to the formation of boron vacancies within the C-B-C chains along the c-axis under mechanical stress. To extend its plastic regime to higher constraints, the proposed approach is to strengthen the C-B-C chains that link the icosahedra of B4C. The objective is to substitute Boron atoms in the chains with Silicon using high pressure and high temperature (HP-HT). Thus, our aim is to investigate the HP-HT synthesis of Si-doped B4C phase, ensuring the absence of parasitic Si-C or Si-B compounds, through the direct reaction between molten Silicon and solid Boron carbide. This synthesis will be performed under HP-HT conditions where Silicon is liquid, preventing the formation of unwanted compounds.