The spray-pyrolysis of borazine at 1400 °C under nitrogen generates boron nitride (BN) nanoparticles (NPs). The as-prepared samples form elementary blocks containing slightly agglomerated NPs with sizes ranging from 55 to 120 nm, a Brunauer-Emmett-Teller (BET)-specific surface area of 34.6 m² g⁻¹ and a helium density of 1.95 g cm⁻³. They are relatively stable in air below 850 °C in which only oxidation of the NP surface proceeds, whereas under nitrogen, their lower size affects their high temperature thermal behavior in the temperature range of 1450–2000 °C. Nitrogen heat-treated nanostructures have been carefully analyzed using X-ray diffraction, electron microscopy and energy-dispersive X-ray spectroscopy. The high temperature treatment (2000 °C) gives hollow-cored BN-NPs that are strongly facetted, and after ball-milling, hollow core-mesoporous shell NPs displaying a BET-specific surface area of 200.5 m²·g⁻¹ and a total pore volume of 0.287 cm³·g⁻¹ were produced. They have been used as host material to confine, then destabilize ammonia borane (AB), thus improving its dehydrogenation properties. The as-formed AB@BN nanocomposites liberated H₂ at 40 °C, and H₂ is pure in the temperature range 40–80 °C, leading to a safe and practical hydrogen storage composite material.

The purpose of this paper is to emphasize the improvement of Zr-based ceramics properties as a function of addition of Ce ions in the structure of the original ceramics. The structural investigations proposed in this paper cover X-ray, and neutron diffraction offered the first indication of the variation of the phase composition and the structural parameters, micro-hardness measurements as well as non-destructive evaluations in order to analyze the structural properties of these materials with utmost importance in fields such as medicine, where these composite materials are used in hip-implants or dental implants/coatings. In combination of Resonant Ultrasound Spectroscopy, which makes use of the resonance frequencies corresponding to the normal vibrational modes of a solid in order to evaluate the elastic constants of the materials, we emphasize a unique approach on evaluating the physical properties of these ceramics, which could help in advancing the understanding of properties and applications in medical fields.

TiMoZrTaSi alloys appertain to a new generation of metallic biomaterials, labeled high-entropy alloys, that assure both biocompatibility as well as improved mechanical properties required by further medical applications. This paper presents the use of nondestructive evaluation techniques for new type of alloys, TiMo₂₀Zr₇Ta₁₅Si_x, with x = 0; 0.5; 0.75; 1.0, which were obtained by vacuum melting. In Ti alloys, the addition of Mo improves tensile creep strength, Si improves both the creep and oxidation properties, Zr leads to an α crystalline structure, which increases the mechanical strength and assures a good electrochemical behavior, and Ta is a β stabilizer sustaining the formation of solid β-phases and contributes to tensile strength improvement and Young modulus decreasing. The effects of Si content on the mechanical properties of the studied alloys and the effect of the addition of Ta and Zr under the presence of Si on the evolution of crystallographic structure was studied. The influence of composition on fracture behavior and strength was evaluated using X-ray diffraction, resonant ultrasound spectroscopy (RUS) analyses, SEM with energy dispersive X-ray spectroscopy, and acoustic emission (AE) within compression tests. The β-type TiMo₂₀Zr₇Ta₁₅Si_x alloys had a good compression strength of over 800 MPa, lower Young modulus (69.11–89.03 GPa) and shear modulus (24.70–31.87 GPa), all offering advantages for use in medical applications.