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Abstract: Nanocomposites are currently attracting significant attention in the energy sector, particularly for storage applications. However, controlling interfacial compatibility remains a challenge. This work introduces a novel interfacial functionalization strategy that enables the achievement of exceptional dielectric properties and addresses the persistent issue of poor filler–matrix interaction in nanocomposites. A poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix was filled with lead-free BaTi0.89Sn0.11O3 (BTS11) nanoparticles, which exhibit ultra-high piezoelectric performance near ambient temperature. These nanoparticles were functionalized with various modifying agents, including ethylenediamine (EDA), polyvinylpyrrolidone (PVP), polydopamine (PDA), and 3-aminopropyltriethoxysilane (APS). The study demonstrated that the functionalized HO-BTS11@modifier/PVDF-HFP nanocomposites exhibit distinct dielectric characteristics depending on the modifying agent. The HO-BTS11@EDA/PVDF-HFP nanocomposites, which included hydroxylated HO-BTS11 nanoparticles modified with EDA, outperformed other modified systems with the maximum energy storage efficiency (~ 77%) and a dielectric permittivity of 70 at 1 kHz. EDA with small molecular size, low polarity, and ability to form hydrogen bonds enable improved interfacial adhesion with the hydrophobic PVDF-HFP matrix making the composite suitable for enhancing energy storage performance. This selective functionalization strategy not only provides new insights into interface engineering but also offers a promising pathway for the development of high-performance materials for energy storage and harvesting devices, embedded capacitors, flexible electronics, and next-generation dielectric systems.
Keywords: nanocomposites, interfacial functionalization, piezoelectric properties, dielectric properties
Published in DiRROS: 19.01.2026; Views: 190; Downloads: 31
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Keywords: Sicilian landraces, Cultivar comparison, Glucosinolates, TPC, nutritional properties
Published in DiRROS: 16.01.2026; Views: 144; Downloads: 52
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Abstract: The microstructure and crystalline orientation evolution of manganese-doped 0.5Ba(Zr0.2Ti0.8)O3—0.5 (Ba0.7Ca0.3)TiO3 (BZT—BCT) thin films deposited on platinized sapphire and multistep-annealed at 850 ◦C are reported. The crack-free 680 nm thick BZT—BCT films with an average lateral grain size of 140 nm exhibit preferential {111} orientation on the surface confirmed by the electron backscatter diffraction (EBSD). Transmission Kikuchi diffraction (TKD) analysis reveals the evolution of preferential {111} and {110} orientation of columnar grains along the film thickness, that is, in the grain-growth direction. The formation of pores at the interface of the film and substrate is observed and related to the migration of pores and grain boundaries. The dielectric permittivity and losses of 840 and 0.02, respectively, at 1 kHz, are measured at room temperature. The maximum polarization and strain at an electric field of 1.2 MV•cm− 1 are about 32 μC•cm− 2 and 0.35 %, respectively. The piezoelectric d33 coefficient of 42 pm•V− 1 was measured by double-beam laser interferometry.
Keywords: 0.5Ba(Zr0.2Ti0.8)O3—0.5(Ba0.7Ca0.3)TiO3 thin films, mycrostructure, crystaline orientation, electromechanical properties
Published in DiRROS: 15.01.2026; Views: 196; Downloads: 73
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Keywords: dredged slurry, geogrid, curing stress, interface properties, pull-out test
Published in DiRROS: 23.12.2025; Views: 710; Downloads: 115
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Abstract: This article deals with the Directed Energy Deposition using Wire and Arc (DED-ARC) for maraging steel cladding. A technology for cladding using Gas Metal Arc Welding (GMAW) has been developed that enables the perfect deposition of maraging steel. The material characterisation was carried out in different material states: in the as-built, solution annealed and aged. The research included visual examinations, optical microscopy, Scanning Electron Microscopy / Energy-dispersive X-ray spectroscopy (SEM/EDS), fractography, hardness testing, tensile testing and impact toughness testing. The as-deposited state exhibited a microstructure with very long crystal grains and microsegregations orientated the direction of the heat sink, consisting of lath martensite. Consequently, a subsequent heat treatment is absolutely necessary in order to obtain a uniform fine-grained microstructure. Two different solution annealing processes were analysed, which allowed us to select the most suitable process for the first step of heat treatment followed by aging. A response surface methodology was used to optimise the aging conditions. The results show that additively manufactured maraging steel reaches a tensile strength of 1947 MPa, a hardness of 657 HV5 and a Charpy impact toughness of 11 J at peak aging condition, which is comparable to conventionally manufactured maraging steel.
Keywords: maraging steel, heat treatment, material properties optimisation, DED-ARC, GMAW, RSM
Published in DiRROS: 08.12.2025; Views: 404; Downloads: 119
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