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The development of advanced membranes for the efficient separation of oil-water emulsions and the degradation of soluble pollutants is crucial for environmental protection. This study presents a Janus composite membrane with Co(CO 3) 0.5 OH·0.11H 2 O nanoneedle arrays, fabricated through electrospinning, membrane assembly, surface hydrophobization, and chemical bath deposition (CBD). By controlling the amount of carbon nanofiber (CNF) and CBD time, the membrane's morphology can be optimized for improved performance. In dead-end filtration driven by gravity, the membrane effectively separates stabilized oil-in-water emulsions and demonstrates strong anti-fouling capabilities. Furthermore, the membrane exhibits significant catalytic activation for peroxymonosulfate (PMS), enabling complete restoration of water flux of polluted membranes and purifying emulsions with soluble organic pollutants. To further enhance anti-fouling performance, a novel separation strategy integrating pulse current is proposed. Under the influence of a pulsed electric field, the membrane achieves a permeate flux nearly twice as high as that observed without this external stimulus, while maintaining high separation efficiency. This research advances Janus nanofiber membrane development via electrospinning techniques and supports sustainable treatment of oily wastewater. A Janus composite membrane is constructed for efficient separation of oil-water emulsions and degradation of soluble pollutants. By incorporating the pulsed electric field with the filtration cell containing the membrane, an antifouling strategy that couples dielectrophoresis, electrophoresis, and bubble mediation is developed to enhance the separation performance for oil-in-water emulsions. [Display omitted] • A Janus composite membrane with Co(CO 3) 0.5 OH·0.11H 2 O nanoneedle arrays is prepared. • The membrane displays stable permeation flux and separation efficiency for emulsions. • The membrane shows substantial PMS activation, enabling effective emulsion purification. • With a pulsed electric field, the anti-fouling of the membranes is enhanced. [ABSTRACT FROM AUTHOR]

A universal strategy that integrates PAA grafting, ion exchange, and in-situ chemical reactions to synthesize photothermal materials for enhanced solar-driven interfacial evaporation and gradient materials for electricity generation, respectively. [Display omitted] • A universal strategy is proposed for the preparation of SDIE and FFIPG materials. • Synthesized nanoparticles or nanoplates are evenly spread on SDIE fabric fibers. • A combination of one-way flow and suspension mode is used for fluid evaporation. • All SDIE fabrics achieve excellent evaporation rates at 0.5 cm suspension height. • The fluid flow can constantly generate a potential difference across the FFIPG fabrics. In our contemporary society, addressing the increasingly pressing global resource shortage, particularly the scarcity of vital water resources and energy, is critical for human survival. This paper presents a strategy that integrates PAA grafting, ion exchange, and in-situ chemical reactions to synthesize photothermal materials for enhanced solar-driven interfacial evaporation and gradient materials for electricity generation, respectively. The obtained photothermal material demonstrates exceptional light absorption and photothermal conversion performance. By employing a unique combination of unidirectional flow and suspension mode for water evaporation, remarkable evaporation rates are achieved, with all samples exceeding 2.03 kg m-2h−1. The hybrid mode is also applied to saltwater treatment, where it is found that the evaporation rate is not significantly affected, regardless of the salt concentration. No change in the evaporation rate is observed even after 12 h of continuous treatment with 10 % brine, indicating the robustness and stable performance of the evaporative materials. For the synthesized gradient materials, the flowing fluid can establish a potential difference at both ends of the gradient fabric. The magnitude of open circuit voltage and short circuit current can be controlled by adjusting the measurement distance, the deposited nanoparticles with different polarity and the amount of charge carried. We acquire a maximum output of 209.7 mV using the gradient Cu-S/PAA-cotton fabric, which can be connected in series to power small electronic devices like a digital watch. This research not only advances the design and practical application of high-performance solar evaporators but also illuminates a novel pathway for developing electricity-generating materials. [ABSTRACT FROM AUTHOR]

A transparent TiO 2 -C@TiO 2 -C free-standing film has been synthesized by two-step hydrothermal method and subsequent thermal annealing. The chemical composition and morphological features of the TiO 2 -C@TiO 2 -C film are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and N 2 adsorption-desorption measurement. The results indicate that the flower-like micro/nanostructure TiO 2 -C particle layers are intimately inhered to porous TiO 2 -C fibers. The fibers in film are interconnected each other to form a three-dimensional reticulate microstructure, and exhibit intense visible light absorption and high adsorptivity of dye molecules. The interaction between TiO 2 and its surface carbon layer in TiO 2 -C particle promotes the generation of Ti- O -C bonds, which leads to effective charge transfer. Under visible-light irradiation, TiO 2 -C@TiO 2 -C film presents enhanced photocatalytic activity for degradation of methylene blue. This work may provide a new viewpoint for designing transparent photocatalytic film for promising applications in heterogeneous photocatalysis. [ABSTRACT FROM AUTHOR]

A nanofiber-based TiO 2 (B)/carbon nanofiber membrane has been synthesized by a facile and effective route that incorporates electrospinning approach with hydrothermal method. The prepared membrane shows high flexibility and hydrophilicity. After treatment with a low surface energy fluorosilane, the obtained superhydrophobic surface endows the membrane a high adhesive force due to the hybrid microstructure of TiO 2 (B) nanotubes and nanoplates on fibers. A water droplet on the surface of the membrane appears spherical in shape, which cannot roll off even when the membrane is bent and turned upside down. When a water droplet dropped from a certain height above the tilt membrane, the rolled water droplet can be stopped after a small displacement. In addition, a 12 μl water droplet can be quickly captured from a hydrophobic surface by curvature change of the superhydrophobic TiO 2 (B)/carbon nanofiber membrane. The membrane with excellent static and dynamic pinning performance to water may be expected to apply to biomedical and microfluidic devices. [ABSTRACT FROM AUTHOR]

Hydroxyapatite ( HAp) hollow microspheres with hierarchically porous structure and nanorice-like architecture units were synthesized by the composite-hydroxide approach. NH4 H2 PO4 was first reacted with hydroxides to form a hydroxide-insoluble M3 PO4 (the term M represents either Na or K). The diffusing M3 PO4 at the liquid-solid interface then reacted with the Ca( OH)2, forming insoluble HAp hollow spheres by Kirkendall process. Results show that when reaction time is increased from 3 to 12 h, the average diameter of the microspheres increased from 2.64 to 4.16 μm. In addition, the size homogeneity of the hollow microspheres was improved gradually due to Ostwald ripening. The prepared hollow microspheres were treated by ultrasound, and nanorice-like component units with a large mass of mesopores (<10 nm) were displayed. These prepared HAp hollow microspheres might be expected to apply to ion adsorption and drug delivery. [ABSTRACT FROM AUTHOR]

Abstract: TiO2/carbon paper composite materials with a hierarchically porous structure were synthesized by employing a filter paper as the support material and carbon source. The resorcinol–formaldehyde–block copolymer nanocomposite formed by the self-assembly of phenolic resin and F127 under acidic condition was selected as modifier of the microstructure of carbon paper. Results show that the as-adjusted carbon paper preserved the nanostructure of a pure carbonized filter paper. An ordered mesostructure was also formed. This micromorphology resulted in the increased specific surface area, as well as micropore and mesopore volumes, compared with the pure carbonized filter paper. When mesoporous TiO2 was deposited on the carbon paper with ordered mesopore by the evaporation-induced self-assembly route, the TiO2/carbon paper composite materials displayed excellent adsorption property and enhanced photocatalytic activity of methylene blue. [Copyright &y& Elsevier]

Abstract: We prepared hydroxyapatite/alumina (HA/Al2O3) porous composite materials by the in situ growth of HA on lamellar Al2O3 ceramics. The procedure comprises two steps. First, lamellar Al2O3 ceramics with aligned pore channels were obtained by freeze casting Al2O3 slurry. Second, as-prepared monoliths were used as scaffolds and subjected to hydrothermal treatment in the HA precursor solution. We characterized the microstructure, chemical composition, and mechanical properties of synthesized HA/Al2O3. Experiment results show that the addition of H2O2 into the reaction solution plays an important role in controlling the microstructure of the cultivated HA. The formation of HA has no obvious influence on the lamellar architecture of Al2O3 ceramics. The prepared composite materials exhibit superior compressive strength. Combination of the high strength of lamellar Al2O3 with the excellent biological properties of HA increases the potential of obtained HA/Al2O3 for load-bearing biological applications. [Copyright &y& Elsevier]

Abstract: The porous ZrO2 ceramics with ultra-high porosity were produced by combining phase change, heat exchange and freeze drying process of ZrO2 slurries during decompression environment. The prepared slurry was first cooled to near the supercooling point, and then the supercooled slurry was placed on decompression system to induce foaming and solidification until the decompress-freezing process of the slurry completed. After drying and sintering of the green part, an as-prepared ceramic with porosity more than 93% was obtained. It was shown that the porous ceramic was typically composed of large spherical cells, interconnected by near circular windows. Although the mechanical properties in obtained ceramics are not enough to resist high stress, porous ceramics with a number of pores in cell walls and struts may be expected to be applied in high thermal insulation process. [Copyright &y& Elsevier]

Abstract: Hierarchically porous silica ceramics with unidirectionally aligned channel morphology have been synthesized by in situ mineralization of soluble starch monolith. The procedure followed two steps. First, soluble starch monoliths with well-defined uniaxial macroporous structure were prepared by unidirectional solidification process of starch hydrosol or starch hydrogel. Second, such an as-prepared artificial monolith, used as template, was soaked into a surfactant-templated sol–gel solution to mineralize the existing channel structure. It was shown that the macropore size, wall thickness, and macropore morphology in obtained soluble starch materials may be tuned in a certain range, through adjusting the concentration of starch slurry. When initial concentration changed from 10 wt.% to 15 wt.%, the macropore size of soluble starch materials decreased, while the wall thickness increased. Through the second step, porous silica ceramics were obtained after drying and calcining of organic–inorganic hybrid silicate compounds from solution. These resulting products preserved template microstructure in great detail and exhibited narrow macropore size distributions. It was observed that when the soaking time increased from 36h to 84h, the average pore size of the silica ceramics was decreased from 4.1μm to 3.6μm. In addition, in nanopore regime, all the silica monoliths obtained presented a coexistence of uniform worm-like nanopore and lamellar phase feature, and large BET and microporous surface area. [Copyright &y& Elsevier]

Two hierarchically porous silica ceramics with unidirectionally aligned channel morphology have been in situ synthesized by using soluble starch monoliths with well-defined uniaxial macroporous structure as template. Both these ceramics faithfully inherit the structure of soluble starch templates and show a large BET surface as well as a microstructure of uniform worm-like nanopores and a lamellar phase. These materials may be suitable for use in various separation and reaction processes. [Copyright &y& Elsevier]

Abstract: Experiments have been performed to show that the mechanical properties of alumina porous ceramics may be improved by introducing glycerol into the raw slurries and then casting them under a constant cooling rate. The effects of glycerol on the freeze casting process and thereby on the microstructure and mechanical properties of porous ceramics obtained are investigated. It is shown that the addition of glycerol will increase both the slurry viscosity and sample sintered density. SEM images for microstructure of the final ceramics reveal that a good connection between ceramic lamellae has been promoted. This connection makes as-prepared porous ceramics obtain high mechanical properties. For the 30vol.% alumina slurry with glycerol, the axial and radial compression strengths reach to, respectively, 255.1MPa and 105.8MPa. [Copyright &y& Elsevier]

A Janus Cu(OH) 2 @Cu 2 O/Cu mesh was constructed, which successfully used for unidirectional liquid transport and in situ dual-functional water purification with high efficiency. • A Janus Cu(OH) 2 @Cu 2 O/Cu mesh with controllable wettability is synthesized. • In situ reduced Cu 2 O NPs deposit on the Cu(OH) 2 to form a core-shell nanoneedle. • A unidirectional water transport behavior is obtained by adjusting irradiation time. • The mesh exhibits in situ dual-functional water purification with high efficiency. A Janus Cu(OH) 2 @Cu 2 O/Cu mesh has been synthesized by UV irradiation and in situ hydrazine vapor reduction of superhydrophobic Cu(OH) 2 /Cu mesh prepared by electrochemical anodization of Cu mesh followed by ODS modification. The Cu 2 O nanoparticles derived from partial reduction of Cu(OH) 2 deposit on the Cu(OH) 2 to form a core-shell heterostructure, which endows the as-prepared mesh with micro/nanoscale hierarchical morphology. The wettability of different sides of the mesh can be easily controlled by tuning irradiation time and subsequent reduction. As a result, a unidirectional water penetration phenomenon can be obtained. In addition, based on the asymmetric wettability as well as the photocatalytic activity of the Cu(OH) 2 @Cu 2 O nanoneedle decorated mesh, the ultrahigh permeation flux and high separation efficiency with excellent in situ photocatalytic ability can also be achieved. This work may provide a rational and convenient strategy to construct Janus mesh with visible light photocatalysis toward in situ dual-functional water purification. [ABSTRACT FROM AUTHOR]

Key message: The HaOr5 resistance gene is located in a large genomic insertion containing putative resistance genes and provides resistance to O. cumana, preventing successful connection to the sunflower root vascular system. Orobanche cumana (sunflower broomrape) is a parasitic plant that is part of the Orobanchaceae family and specifically infests sunflower crops. This weed is an obligate parasitic plant that does not carry out photosynthetic activity or develop roots and is fully dependent on its host for its development. It produces thousands of dust-like seeds per plant. It possesses a high spreading ability and has been shown to quickly overcome resistance genes successively introduced by selection in cultivated sunflower varieties. The first part of its life cycle occurs underground. The connection to the sunflower vascular system is essential for parasitic plant survival and development. The HaOr5 gene provides resistance to sunflower broomrape race E by preventing the connection of O. cumana to the root vascular system. We mapped a single position of the HaOr5 gene by quantitative trait locus mapping using two segregating populations. The same location of the HaOr5 gene was identified by genome-wide association. Using a large population of thousands of F2 plants, we restricted the location of the HaOr5 gene to a genomic region of 193 kb. By sequencing the whole genome of the resistant line harboring the major resistance gene HaOr5, we identified a large insertion of a complex genomic region containing a cluster of putative resistance genes. [ABSTRACT FROM AUTHOR]

Abstract: Gathering the photocatalysis of semiconductors and the superduper electron transmittability of graphene, graphene-based semiconductor photocatalytic composites are attracting increasing interest of researchers. In this paper, a Cu2O/reduced-graphene-oxide (Cu2O/RGO) nanocomposite was prepared via a facile wet-reduction process, for removal of organic pollutants. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV–vis spectrophotometry. The nanocomposite is composed of Cu2O nanoparticles with sizes of 100–500nm attached to the RGO sheets. For photodegradation of methylene blue (MB) under visible light, the Cu2O/RGO nanocomposites exhibited greatly enhanced photocatalytic efficiency compared to the pure Cu2O nanoparticles. The enhanced photocatalytic performance was mainly ascribed to the increased adsorptivity to organic dye as well as the efficient charge transportation and separation from Cu2O to RGO. [Copyright &y& Elsevier]

Abstract: In spite of the well-known desirable properties of organic PCMs like stearic acid (SA) for thermal energy storage, the leakage, high phase change temperature and poor thermal conductivity limit their direct applications. In this study, a novel shape-stabilized phase change material of stearic acid–graphene oxide (SA–GO) was fabricated by imprisoning SA in the interlayer spaces of the multilayer GO, based on the capillary action and interfacial interaction. The as-prepared SA–GO composites were characterized by the X-ray diffractometer, scanning electronic microscope, Fourier transformation infrared spectroscope, thermogravimetry analyzer and differential scanning calorimeter. The thermal properties of SA–GO composite could be tailored by adjusting SA/GO mass ratio. The SA–GO composite prepared from SA/GO mass ratio of 1 exhibited greatly decreased melting point (Tm ) and freezing point (Tf ) relative to those of the pristine SA, and the melting latent heat is 55.7J/g, corresponding to the thermal storage capability rate of 82.4%. The thermal behaviors of SA–GO composites with different SA/GO mass ratios were explained from the point of confinement effect, which were further confirmed by comparison with those of SA–graphite and SA–active carbon composites. The present research provides a novel shape-stabilized composite PCM for the thermal energy storage as well as some new insights into phase change behavior of organic PCMs in nanoconfined geometries. [Copyright &y& Elsevier]

Aims: Orobanche cumana is an obligate root parasite which specifically infects roots of Helianthus annuus L., causing severe yield and economic losses in agricultural fields worldwide. For an efficient control strategy, it is necessary to understand specialized host defense mechanisms and the pathogenesis of O. cumana during underground interaction with the host. Methods: RNA-Seq was used to simultaneously assess the transcriptome of each of two contrasting sunflower cultivars with O. cumana during their post-attachment interactions. Secretome prediction was applied to identify O. cumana proteins from its transcriptome. Results: Infection of O. cumana triggered insufficient defense responses in the susceptible cultivar as compared to the resistant one, probably due to the failure to fully recognize parasite effectors. Secretome prediction from the O. cumana transcriptome enabled robust identification of 180 proteins associated with O. cumana penetration and infection. Functional annotation of these proteins revealed that they were associated with cell wall degradation, nutrient acquisition and pathogenesis. Additionally, a candidate effector containing a PAR1 domain from O. cumana was preliminarily identified as a potential suppressor of plant defense responses. Conclusions: Secretome prediction shed lights on the molecular mechanisms that O. cumana deployed to manipulate host defense. Successful infection of O. cumana inhibited host defense responses and turned host roots from a sink to a source for efficient nutrient flux towards the parasite. In summary, these findings provide insight into the mechanism underlying O. cumana infection and are important in understanding parasitic-host plant interaction. [ABSTRACT FROM AUTHOR]

Exploiting photocatalysts with improved properties for solar-driven chemical reactions is of great significance in developing green chemistry. Here, a series of Au/CeO 2 hybrid nanofibers with different Au loadings have been fabricated by a simple method of electrospinning followed by calcination in air. The particle size and plasmonic absorption of Au nanoparticles (NPs) loaded in the nanofibers were analyzed and found to vary with the dosage of chloroauric acid in the precursor solution. The Au/CeO 2 hybrid nanofibers were used as photocatalysts for selective oxidation of benzyl alcohol to benzaldehyde with O 2 under simulated sunlight and visible light (>420 nm), respectively. The results showed that introducing Au NPs into CeO 2 nanofibers induced a great improvement in photocatalysis. The degree of improvement increased first and then decreased with the increase in Au loading, reaching an optimal level over 0.5 wt.% Au-loaded CeO 2 nanofibers. The photocatalytic reaction presents a very high selectivity of 100% for benzaldehyde, which is important for organic synthesis. The transient photocurrent responses of the Au/CeO 2 catalysts were also tested for corroborative evidence. After detailed discussion of various factors including plasmonic absorption, charge transfer, and surface activity of the photocatalyst, a possible mechanism for the photocatalytic oxidation of benzyl alcohol occurring at the Au–CeO 2 interface was proposed. [ABSTRACT FROM AUTHOR]

Exploiting photocatalysts/catalysts with characteristics of low cost, high reactivity and easy recovery is of great significance for energy efficiency and environmental remediation. Herein, CuO/TiO 2 hybrid nanofibers with different CuO contents were fabricated by a simple and low-cost method of electrospinning followed with calcinations in air. The hybrid nanofibers possess some distinct merits including mesoporous structure, extended light response range, and large TiO 2 /CuO interface. The CuO/TiO 2 hybrid nanofibers showed improved photocatalytic activity for organic dye degradation under both simulated sunlight (UV–vis) and visible light (λ > 420 nm), compared with pure TiO 2 nanofibers. Both processes exhibited humplike activity dependence upon CuO addition, with a peak at 1 wt.%-CuO content under UV–vis light and a peak at 5 wt.%-CuO content under visible light, respectively. The mechanism for the CuO-content dependent photocatalysis was discussed with the photoelectrochemical analysis in evidence. Moreover, the CuO/TiO 2 hybrid nanofibers exhibited very high catalytic efficiency for the reduction of nitrophenols by sodium borohydride, and the apparent reaction rate constants ascended with the increased CuO content. The optimized CuO/TiO 2 nanofibers are expected to act a highly efficient catalyst to replace the noble metals in this field. Therefore, this work demonstrated a convenient case for the exploitation of noble-metal-free catalysts with high efficiency, to meet the increasing demands of industrial applications at reduced costs. [ABSTRACT FROM AUTHOR]

The Au/TiO 2 hybrid nanofibers composed of mesoporous TiO 2 nanofibers and Au nanoparticles were synchronously fabricated by integrating a facile electrospinning technique and subsequent annealing in air. The Au loading content in the hybrid nanofibers was regulated by varying the dosage of chlorauric acid added in the precursor solution. The compositions, microstructures and optical response properties of the Au/TiO 2 hybrid nanofibers were characterized. The UV–vis spectra of the as-prepared hybrid fibers reveal two absorption bands belonging to the band gap absorption of TiO 2 and the surface plasmon resonance (SPR) of Au nanoparticles. For the catalytic reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride, the apparent reaction rate constant is raised but TOF value of the catalyst decreases, as the Au loading amount in the hybrid fibers increases. This is because the Au nanoparticles with smaller sizes have higher total surface areas at the same weight and therefore show higher catalytic activity. This method for producing Au/TiO 2 hybrid nanofibers is versatile and can be extended to the fabrication of other hybrid nanofibers composed of various noble metal nanoparticles and other mesoporous metal oxide nanofibers, designing of highly efficient catalysts for more important chemical reactions. [ABSTRACT FROM AUTHOR]

Incorporating plasmonic Ag nanoparticles into mesoporous metal–oxide (MMO) semiconductors will achieve collective effect to greatly increase the photocatalysis. This work demonstrated a general two-step method to obtain diverse Ag/MMO composite photocatalysts with plasmon-enhanced photocatalytic activity. Several typical MMO (TiO 2 , ZnO, and CeO 2 ) semiconductors were synthesized by integrating evaporation-induced self-assembly and in situ pyrolysis of metal precursors. Different amounts of Ag nanoparticles were then loaded in these MMO semiconductors through a facile photodeposition process. The Ag nanocrystals with sizes of 50–100 nm were embedded in MMO semiconductors, endowing the Ag/MMO composites notable visible light absorption. The photocatalytic activities of the as-prepared diverse photocatalysts were studied systematically. The influencing factors including MMO species, mesoporous structure, and Ag loading amount on the photocatalytic activity were discussed in detail. The Ag/MMO composites exhibited much improved photocatalytic activity than their pure MMO semiconductors. The mesoporous TiO 2 with the Ag-loading amount of 5 wt.% exhibited the best photocatalytic performance for photodegrading both methylene blue and phenol under a simulated sunlight. The enhancement in photocatalysis is attributed to the synergistic effect of the mesoporous structures for efficient mass transfer as well as the Ag nanoparticles providing plasmonic enhanced light absorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • First preparation of dodecahedrons CeO 2 /Co/C for microwave absorption. • An excellent reflection loss of −68.83 dB at 5.92 GHz with ultra-thin thickness. • Effective absorption bandwidth up to 4.16 GHz under a single thickness. CeO 2 /Co/C dodecahedrons composites with excellent microwave absorption performance were synthesized by using a hydrothermal method. ZIF-67/CeO 2 was first prepared by introducing CeO 2 into the precursor of ZIF-67 and then CeO 2 /Co/C composite was obtained after heat treatment. Impedance matching of the samples could be well adjusted by controlling the content of CeO 2. Unique dodecahedral structure for more interfacial reflection and cerium dioxide oxygen vacancies enhance microwave absorption performance. Specifically, the CeO 2 /Co/C exhibited a minimum reflection loss of −68.83 dB is observed at 5.92 GHz, while the thickness was 3.69 mm. The introduction of CeO 2 effectively enhanced the impedance matching of the materials and improved the microwave absorption performance. Therefore, this CeO 2 /Co/C composite is a promising microwave absorber material with high performance. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the rare-earth oxide La2O3 combined with Al2O3 served as sintering additives and low-cost α-SiC powder were exploited successfully to prepare dense short carbon fiber reinforced SiC composites by hot-pressing (HP) sintering. The results of the experiments proved that the combination of Al2O3 and La2O3 sintering additives system was effective to promote densification of the hot-pressed Cf/SiC composites. The influence of the annealed temperature on the micro-structure and mechanical properties of the Cf/SiC composites was investigated in details. The proper annealed condition is favorable to improve the room temperature mechanical properties. The most interesting phenomenon was observed that silicon carbide nano-whisker structure was formed in the material which was annealed at 1750°C for 1h. It is undoubted that nano-whisker structure would promote fracture toughness. The combination of grain bridging, crack deflection and nano-fiber debonding can improve fracture toughness. [Copyright &y& Elsevier]

Abstract: Hot-pressed silicon carbide composites reinforced with carbon fiber were prepared. Aluminum and yttrium oxides served as sintering additives and low-cost α phase SiC was used as starting powder, instead of the more expensive β-SiC. In the sintering process, the SiC-matrix grains grew larger via solution reprecipitation. Reaction of Al2O3/Y2O3 additives with SiO2 on the surface of SiC or its oxidation products caused formation and distribution of a low-eutectic-point phase around the SiC grains and carbon whiskers. Such amorphous films can be found in triple-junctions and boundaries of SiC grains. Excess sintering additives improve the room-temperature flexural strength, but reduce the fracture toughness. Coupled with a higher sintering temperature, they contribute to the diffusion of yttrium ions into carbon fiber, and make the reaction layer thicker. Non-homogeneous amorphous inclusions between grains and whiskers are harmful for mechanical properties. A combination of grain bridging, crack deflection and whisker debonding can improve fracture toughness. [Copyright &y& Elsevier]