Nanostructured Composite Materials Research Articles

On the prospects of application of nanostructured heterophase polyfunctional composite materials inengine building industry

The paper gives a brief review of properties and applications of developed extra-hard nanostructured composite materials and coatings based on them. The presentresearch suggestsaerospace applications of nanostructured composite materials based on carbides, carbonitrides and diboridesof transition and refractory metals. To improve the technical and economic performance of gas turbine engines, it is advisable to use new composite structural materials whose basic physicomechanical properties are several times superior to traditional ones. The greatest progress in developing new composites should be expected in the area of materials created on the basis of polymer, metal, intermetallic and ceramic matrices. Currently components and assemblies of gas turbine engines and multiple lighting power units with long operation life and durability will vigorously develop. Next-generation composites are studied in all developed countries, primarily in the United States and Japan.

Highly Sensitive Detection of Gallic Acid in Food Samples by Using Robust NiAl2O4 Nanocomposite Materials

We have successfully synthesized nanostructured cubic NiAl2O4 nanoparticles for the selective electrochemical determination of gallic acid (GA) and the prepared nanostructured composite material was characterized by (X-ray diffraction, Fourier transform infrared spectroscopy, and field-emission scanning electron microscopy analyses. The cubic NiAl2O4 nanoparticles had average sizes of ∼ 26–30 nm as calculated from XRD and SEM measurements, respectively. GA-detection performance was also evaluated by cyclic voltammetry and amperometry method. NiAl2O4 glassy carbon electrode showed excellent performance in GA detection with a linear range, detection limit (SNR = 3 sb/S), limit of quantitation (LOQ = 10 sd/S) and sensitivity value of 0.03–551.18 μM, 0.018 μM, 0.057 μM and 9.019 μM mA−1 cm−2, respectively. The GA sensor was also used in real-sample analysis using food samples, and results showed the practicability of the proposed sensor.

Innovative synthesis of nanostructured composite materials by a spray-freeze drying process: Efficient catalysts and photocatalysts preparation

The spray-freeze-drying (SFD) approach was successfully applied for the preparation of nanostructured porous mixed oxides with high surface area. The preparation of different composite materials and the encapsulation of metal nanoparticles in inorganic matrix was easily obtained using this interesting technique. In particular, TiO2-SiO2 mixed-oxides were produced at different compositions using the colloidal heterocoagulation of very stable sols, associated with SFD. Moreover, its versatility allowed the incorporation of metal. This synthetic approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution. The prepared materials were active and selective in the reduction of 5-hydroxymethyl-2-furfural (HMF) to 2,5-bishydroxymethylfuran (BHMF) and in the photodegradation of rhodamine B (RhB), used as a as a stain model.These encouraging results pave the way for the use of this method for the homogeneous embedding of different typologies of catalytic active phases (metal nanoparticles, inorganic complexes, enzyme) into any kind of support (inorganic, organic, polymeric) minimizing the possibility of phase separation on a molecular scale, as also demonstrated for drugs.

Synthesis and Rapid Consolidation of W-1.5 ZrO2 Composite

ZrO2 is a candidate material for hip and knee joint replacements because of its excellent combination of biocompatibility, corrosion resistance and low density. However, the drawback of pure ZrO2 is a low fracture toughness at room temperature. One of the most obvious tactics to cope with this problem is to fabricate a nanostructured composite material. Nanomaterials can be produced with improved mechanical properties(hardness and fracture toughness). The high-frequency induction heated sintering method takes advantage of simultaneously applying induced current and mechanical pressure during sintering. As a result, nanostructured materials can be achieved within very short time. In this study, W and ZrO2 nanopowders are mechanochemically synthesized from WO3 and Zr powders according to the reaction(WO3 + 3/2 Zr→W+ 3/2 ZrO2). The milled powders are then sintered using high-frequency induction heating within two minutes under the uniaxial pressure of 80MPa. The average fracture toughness and hardness of the nanostructured W-3/2 ZrO2 composite sintered at 1300°C are 540 kg/mm2 and 5 MPa·m1/2, respectively. The fracture toughness of the composite is higher than that of monolithic ZrO2. The phase and microstructure of the composite is also investigated by XRD and FE-SEM.

The study of the structure and properties of nanostructured biodegradable thermoplastic composite

Increased requirements for polymer materials and the expansion of their application fields create the prerequisites for the creation of new composite materials. The most promising matrix for the biocomposite material is 2-hydroxypropionic (lactic) acid, the unique capabilities of which are manifested as a result of modification by inorganic mineral fillers of nanometric size. The combination of such properties as Biodegradability and biocompatibility is particularly valuable in this polymer. Nanostructured composite materials, consisting of polylactic acid and mineral fillers, acquire a significant improvement in properties compared to the properties of a pure polymer. Biodegradable films containing a layered natural mineral from the class of metasilicates were obtained by the method of irrigation of molding solutions. Trichloromethane was used as a solvent for the preparation of molding solution. The structure and properties of a nanostructured thermoplastic composite are studied. It is shown that the filler is evenly distributed in the polymer structure, affects the size of the crystal formations, the size of the crystallites increases. The introduction of a nanostructuring mineral into a biopolymer increases the thermal stability of the composite, which is due to the high resistance to high temperatures of the initial micro-reinforcing mineral filler, which does not decompose to a temperature of 1000-1100 0C. The influence of layered natural mineral from the class of metasilicates on the deformation and strength properties of biocompositeis established: the strength is maintained and the relative elongation at material rupture is slightly reduced. The ability to biodegradation and very low toxicity allow the use of nanostructured composite material based on 2-hydroxypropionic (lactic) acid in biomedical, pharmaceutical, environmental and industrial fields. The development of biodegradable composite material will solve the current domestic problems of polymers for medical purposes.

Oxygen reduction reaction activity and long-term stability of platinum nanoparticles supported on titania and titania-carbon nanotube composites

Aiming at Pt nanoparticle catalysts for application in polymer electrolyte membrane fuel cell (PEMFC) cathodes, which are highly active and more corrosion resistant under realistic mobile applications than common Pt/C catalysts, we have prepared and investigated Pt catalysts supported on highly stable, nanostructured composite materials containing carbon nanotubes (CNTs) and titania. TiO2@CNT composite materials are synthesized via sol-gel processing and subsequent Pt deposition. The physical and electrochemical properties as well as the stability of these catalysts, as determined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), rotating ring disk electrode (RRDE) measurements and accelerated degradation tests (ADTs), were compared with those of commercial Pt/C, Pt/TiO2 and Pt/CNT. The measurements reveal a high activity of the composite catalyst, comparable to that of the Pt/C catalyst, but an almost complete loss of ORR activity upon an ADT procedure simulating start-stop behavior. In contrast to carbon supported catalysts, where degradation is mainly associated with corrosion at high potentials, we find the titania supported catalysts to mainly suffer from the reductive treatment in the ADTs. Consequences for the use of Pt catalysts supported on reducible oxides such as TiO2 as cathode catalysts in fuel cell applications are discussed.

Improvement of friction units of power plants by aplying ceramic composite spray coatings

Modifying the working surface of a product by applying protective and functional coatings makes possible considerable changes in the mechanical, optical, electrical, magnetic, thermal and chemical properties of the original structural material, its real surface, producing articles with protective, for example, anti-corrosion, wear-resistant and other properties. We investigated the possibility of improving the friction units of aircraft power plants by applying nanostructured ceramic composite spray coatings. A heavily loaded bearing forming a part of the gearbox of a turbojet engine is used as a prototype of the friction unit. The advantages and drawbacks of improved friction units as compared to production models and their prototypes made according to an improved technology are assessed. The results obtained during the experimental work are presented. A positive conclusion is made about the use of nanostructured composite materials in the development of friction units; the most favorable method of coating is determined.

Improved thermoelectric properties of nanostructured composites out of Bi1−xSbx nanoparticles and carbon phases

Thermoelectric figures of merit of ZT ≈ 0.4 at room temperature were achieved in nanostructured composite materials prepared by uniaxial pressing of Bi1−xSbx nanoparticles and 0.3 wt.% of a carbon phase. This constitutes a significant improvement of the low-temperature thermoelectric material Bi1−xSbx and strongly suggests the possibility of employing these materials in efficient thermoelectric devices working at room temperature. Interestingly, the beneficial effect of the carbon phase added to nanostructured Bi1−xSbx is the same for either carbon nanotubes or active carbon. This finding is attributed, on the one hand, to a combination of electronic band gap engineering due to nanostructuring and energy filtering due to graphene-like interlayers between Bi1−xSbx grains and, on the other hand, to modified phonon scattering at the grain boundaries and additional phonon scattering by agglomeration sites of carbon material on the μm scale.

Thermal and electrical properties of carbon nanotube-based epoxy composite materials

The novel properties of carbon nanotubes have generated much interest in nanostructured polymer composite materials. The effect of multi-walled carbon nanotube aspect ratio on the thermal and electrical properties of nanostructured epoxy composite materials was investigated both experimentally and theoretically. Both thermal and electrical conductivity measurements were performed, and comparisons were made between the results obtained for the nanostructured composite materials containing carbon nanotubes with different aspect ratios. Potential applications of these nanostructured composite materials were discussed, and design recommendations were also made. The numerical and experimental results indicated that the aspect ratio plays an important in determining the physical properties of the nanostructured epoxy composite materials. The electrical conductivity of the nanostructured composite materials is highly dependent on the aspect ratio of carbon nanotubes. In contrast, the aspect ratio plays a considerable role in the thermal conductivity of the composite materials. Multi-walled carbon nanotubes are capable of improving both thermal and electrical performance of the polymer matrix. In contrast to the orders of magnitude enhancement in electrical conductivity with a very low loading of carbon nanotubes, the thermal conductivity of the composite materials has shown only moderate improvement. The improvement in physical properties of the composite materials can be interpreted in terms of carbon nanotube networks.

On the nonlinear dynamics of electro-magnon excitations in the BaTiO3/Fe nanostructured multiferroic composite material

We study the motion of an electric excitation between the ferroelectric (FE) and the ferromagnetic (FM) components of a MultiFerroic (MF) composite material by analysing the transfer of energy from the FE side to the FM one. The transmission process of the electric excitation, which has an envelope soliton shape, is studied for a one-dimensional model of the barium titanate/iron (BaTiO3/Fe) composite. From the transmission spectrum, we determine the most favourable range of the values of the amplitude and of the width of the initial excitation for the transmission of the FE energy to the FM part of the MF material. From the numerical analysis, it is shown that the position in which we excite the FE component strongly impacts on the solitary wave dynamics. We have also realised that, for some initial positions and suitable range of values of the amplitude and width of the excitation of the polarization, we get a stationary localised magnetic excitation in the FM part of the MF material that lasts for a long time. Such a phenomenon, which originates from a curvilinear trajectory of the incoming excitation is promising enough for the implementation of non-volatile memories based on MF composite materials.

Physicochemical and Electrophysical Properties of Metal/Semiconductor Containing Nanostructured Composites

The properties of nanostructured composites based on metal oxides and metal–polymer materials are analyzed, along with ways of preparing them. The effect the interaction between metal and semiconductor nanoparticles has on the conductivity, photoconductivity, catalytic activity, and magnetic, dielectric, and sensor properties of nanocomposites is discussed. It is shown that as a result of this interaction, a material can acquire properties that do not exist in systems of isolated particles. The transfer of electrons between metal particles of different sizes in polymeric matrices leads to specific dielectric losses, and to an increase in the rate and a change in the direction of chemical reactions catalyzed by these particles. The interaction between metal-oxide semiconductor particles results in the electronic and chemical sensitization of sensor effects in nanostructured composite materials. Studies on creating molecular machines (Brownian motors), devices for magnetic recording of information, and high-temperature superconductors based on nanostructured systems are reviewed.

Nanostructured Composite Materials Based on Al–Mg Alloy Modified with Fullerene C60

Nanostructured composite materials (NCMs) based on Al–Mg alloy AMg6 (1560) modified with fullerene C60 are obtained by milling of initial materials in a high-energy planetary ball mill and the subsequent hot extrusion of powder mixtures. The structure, phase composition, and physical and mechanical properties of NCMs obtained are studied. It is shown that introduction of 0.3 wt % of fullerene C60 into NCMs prevents agglomeration of the particles during milling, intensifies the particle size reduction, and makes it possible to obtain an average aluminum crystallite size less than 50 nm. After consolidation of the powder mixtures by direct hot extrusion, the obtained materials demonstrate an increase in tensile strength up to 820 MPa and in bending strength up to 1.11 GPa. In this case, the density of NCMs is 2.61 g/cm3, which provides a value of the specific strength on the level of titanium alloys and fiberglass.

Advanced composite alloys for constructional parts of robots

In recent years all over the world special attention has been paid to the development and implementation of nanostructured materials possessing unique properties and opening fascinating prospects for the development of technical progress in various fields of human activities. A special place can be given to the development of service robots, the market of which is actively developing. There is problem associated mainly with the lack of heat-strengthened alloys which consists in low thermal stability of the alloy properties under the conditions of elevated variable temperatures and loads. The article presents studies to assess the effect of composition, the amounts of refractory nanoscale particles and methods for their introduction into the melt on the structure and properties in nanostructured composite aluminum alloys. The powders of metals, alloys, as well as silicon carbide and aluminum oxide were used to produce the nanostructured powder composite materials. As a result of the research, NPCM compositions containing micro-size particles of transition metals that are carriers of nanosized reinforcing particles and initiators of the formation of an intermetallide of endogenous origin in a melt.

General Synthetic Strategy for Libraries of Supported Multicomponent Metal Nanoparticles.

Nanoparticles comprising three or more different metals are challenging to prepare. General methods that tackle this challenge are highly sought after as multicomponent metal nanoparticles display favorable properties in applications such as catalysis, biomedicine, and imaging. Herein, we report a practical and versatile approach for the synthesis of nanoparticles composed of up to four different metals. This method relies on the thermal decomposition of nanostructured composite materials assembled from platinum nanoparticles, a metal-organic framework (ZIF-8), and a tannic acid coordination polymer. The controlled integration of multiple metal cations (Ni, Co, Cu, Mn, Fe, and/or Tb) into the tannic acid shell of the precursor material dictates the composition of the final multicomponent metal nanoparticles. Upon thermolysis, the platinum nanoparticles seed the growth of the multicomponent metal nanoparticles via coalescence with the metallic constituents of the tannic acid coordination polymer. The nanoparticles are supported in the walls of hollow nitrogen-doped porous carbon capsules created by the decomposition of the organic components of the precursor. The capsules prevent sintering and detachment of the nanoparticles, and their porosity allows for efficient mass transport. To demonstrate the utility of producing a broad library of supported multicomponent metal nanoparticles, we tested their electrocatalytic performance toward the hydrogen evolution reaction and oxygen evolution reaction. We discovered functional relationships between the composition of the nanoparticles and their electrochemical activity and identified the PtNiCu and PtNiCuFe nanoparticles as particularly efficient catalysts. This highlights how to generate diverse libraries of multicomponent metal nanoparticles that can be synthesized and subsequently screened to identify high-performance materials for target applications.

Fabrication of dense nano-laminated tungsten carbide materials doped with Cr3C2/VC through two-step sintering

This work investigates the critical roles of two-step sintering (TSS) and laminated structure on the sintering behavior and mechanical properties of functionally graded WC-TiC-Al2O3 nanostructured composite materials doped with Cr3C2/VC. Results show that excellent mechanical properties are achieved for tailored TSS conditions with a hardness of 27.91 ± 2.3 GPa and a flexural strength of 1423.3 ± 23.5 MPa. The desirable mechanical properties are attributed to the suppressed grain growth without densification deterioration. TSS is more effective in facilitating the favorable dispersion of secondary phase toughening nano-particulates in a WC matrix than conventional sintering (CS). Cr3C2/VC dopant plays an important role in maximizing and shifting the temperature range of the kinetic window for WC-Al2O3 composites. Al2O3 crack deflection, transgranular Al2O3, microcracking, WC crack bridging and plate-like WC crack deflection are the major toughening mechanisms. Residual surface compressive stress induced by the graded structure is also an appreciated contribution to the improvement of mechanical properties.

One-pot electrospinning and gas-sensing properties of LaMnO3 perovskite/SnO2 heterojunction nanofibers

Using nanostructured composite materials is an effective way to obtain high-performance gas sensors. This work used p-type LaMnO3 perovskite-structured semiconductor as a novel promoter for SnO2 nanofibers and studied the gas-sensing characteristics. Nanofibers of 0–2.5-mol% LaMnO3/SnO2 were synthesized via one-pot electrospinning. Compared with pristine SnO2, LaMnO3/SnO2 composite nanofibers exhibited smaller particle size (10–30 nm) and higher BET surface area. XPS revealed that oxygen surface absorption decreased with increasing LaMnO3 content. 0.3-mol% LaMnO3/SnO2 exhibited significantly enhanced ethanol sensitivity relative to pristine SnO2. A response of 20 was obtained at the optimum temperature of 260 °C for 100-ppm ethanol. Higher LaMnO3 loading led to decrease of the ethanol response. The impact of LaMnO3 loading on the sensing behavior of SnO2 nanofibers was discussed in terms of p-n heterojunction formation and changes in the microstructure and catalytic properties.

Synthesis of nanostructured composite material based on nanodiamonds modified by silicon

Composite nanostructured powder nanodiamond–SiC with particles of size from 0.1 to 5 μm is synthesized on the basis of nanodiamonds modified by carbon and silicon under vacuum annealing. A compact diamond composite material consisting of nanostructured grains of size 0.2-0.5 microns is formed as a result of high pressure-high temperature sintering of the powder under the pressure range of 1.0-2.5 GPa. The mechanical milling of the synthesized compacts makes it possible to obtain a polycrystalline diamond micropowder with submicron- and nanocrystalline structure with particles of size up to 50 μm.

Nanomaterials of SHS technology for tribological applications: A review

A review of results of applying the powder technology of self-propagating high-temperature synthesis (SHS) for obtaining various nanomaterials that can be used according to the tribotechnical indentation is given. First, these are low-cost nanopowders of sulfides, oxides, nitrides, carbides, borides, and metals which are suitable as solid lubricants and friction modifiers for liquid and plastic lubricating materials. Second, these are solid compact nanostructured ceramic and composite materials for the fabrication of tribotechnical construction. This type of nanomaterial can be fabricated both ex situ from SHS nanopowders by sintering or introduction into the melt both in situ in one stage from initial powders reagents by gasostatic SHS technology, forced SHS compaction, SHS casting, and SHS in the melt, which considerably simplifies and cheapens the production of such materials. Third, these are SHS materials for the deposition of nanostructured coatings of various thicknesses with a high wear resistance and low friction coefficients, such as nanostructured materials for surfacing and spraying, electrospark alloying electrodes, multicomponent targets for magnetron sputtering, cathodes for vacuum-arc evaporation, and nanodispersed fillers of electrochemical and chemical coatings.

Influence of matrix nature on the functional efficacy of biomedical cell product for the regeneration of damaged liver (experimental model of acute liver failure)

Aim. A comparative analysis of the functional efficacy of biomedical cell products (BMCP) for the regeneration of damaged liver based on biopolymer scaffolded porous and hydrogel matrices was performed on the experimental model of acute liver failure. Materials and methods. Matrices allowed for clinical use were employed for BMCP in the form of a sponge made from biopolymer nanostructured composite material (BNCM) based on a highly purified bacterial copolymers of poly (β-hydroxybutyrate-co-β-oxyvalerate) and polyethylene glycol and a hydrogel matrix from biopolymer microheterogeneous collagen-containing hydrogel (BMCH). Cellular component of BMCP was represented by liver cells and multipotent mesenchymal bone marrow stem cells. The functional efficacy of BMCP for the regeneration of damaged liver was evaluated on the experimental model of acute liver failure in Wistar rats (n = 40) via biochemical, morphological, and immunohistochemical methods. Results. When BMCP was implanted to regenerate the damaged liver on the basis of the scaffolded BNCM or hydrogel BMCH matrices, the lethality in rats with acute liver failure was absent; while in control it was 66.6%. Restoration of the activity of cytolytic enzyme levels and protein-synthetic liver function began on day 9 after modeling acute liver failure, in contrast to the control group, where recovery occurred only by days 18–21. Both matrices maintained the viability and functional activity of liver cells up to 90 days with the formation of blood vessels in BMCP. The obtained data confirm that scaffolded BNCM matrix and hydrogel BMCH matrix retain for a long time (up to 90 days) the vital activity of the adherent cells in the BMCP composition, which allows using them to correct acute liver failure. At the same time, hydrogel matrix due to the presence of bioactive components contributes to the creation of the best conditions for adhesion and cell activity which accelerate the regeneration processes in the damaged liver compared to BMCP on scaffolded matrix. Conclusion. A statistically significant difference was found between the functional efficacy of the BMCP studied based on BNCM and BMCH matrices. BMCP based on hydrogel BMCH matrix was more effective for the regeneration of damaged liver.

Rheological characterization of nanostructured material based on Polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS) block copolymer: Effect of block copolymer composition and nanoparticle geometry

Block copolymer (BCP) nanocomposite systems are of broad interest; however, reports on the role of nanoparticles on microphase separation behavior are rare. The goal of present study is to investigate the preparation of composite nanostructured materials containing Multi-Walled Carbon Nanotubes (MWCNTs) or graphene nanoplates. BCP nanocomposites based on the linear triblock copolymer, Polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS), with different morphological structure were prepared by melt mixing. The results of temperature sweep experiments showed an enhancing effect of both MWCNT and graphene nanosheets on increasing the microphase separation temperature as well as accelerating its kinetic, resulting from the confinement of BCP segments, with graphene nanosheets providing a more severely confined geometry for polystyrene segments in contrast to MWCNTs. Additionally, DMTA results indicated a promotion of the BCP microphase separation by incorporation of nanoparticles. Transient flow measurements followed by time sweep test suggested the existence of a special 3D network microstructure caused by nanoparticles/domain interactions.