Simple Heat Treatment Process Research Articles

Healing potential of hybrid materials for structural composites

The healing potential of light-weight hybrid composites consisting of S-glass and polypropylene fibres in an Araldite LY564 epoxy resin has been investigated. This paper describes a co-mingling process for creating glass–polypropylene hybrid yarns. Cross-ply laminates consisting of hybrid yarns in an epoxy matrix have been tested under low energy impact as well as compression after impact (CAI) loading conditions. The study examines the potential for healing the damage cracks developed during impact, with polypropylene fibres. Key part of this investigation is to evaluate the healing potential of polypropylene fibres through local heating. The study shows that with a simple heat treatment process, significant reduction in the impact induced damage area and a corresponding increase in the compression after impact strength can be achieved; a 65% strength improvement has been measured for the healed specimens when compared to unhealed specimen.

Architecting boron nanostructure on the diamond particle surface

The present study provides an efficient approach for nano-functionalization of diamond powders. Boron nanostructure can be grown on diamond particle entire surface by a simple heat-treatment process. After treatment, various boron nanoforms were grown on the diamond particle surface at different processing temperature. High-density boron nanowires (BNWs) grow on the diamond particle entire surface at 1333K, while nanopillars cover diamond powders when the heat treatment process is performed at 1393K. The influence of the pretreatment temperature on the microstructure and thermal conductivity of Cu/diamond composites were investigated. Cu/diamond composites with high thermal conductivity of 670W(mK)−1 was obtained, which was achieved by the formation of large number of nanowires and nanopillars on the diamond particle surface.

Carbon-supported Fe/Co-N electrocatalysts synthesized through heat treatment of Fe/Co-doped polypyrrole-polyaniline composites for oxygen reduction reaction

In this paper, we synthesized cathode catalysts (PANI-PPYR, Fe/PANI-PPYR, Co/PANI-PPYR and Fe-Co/PANI-PPYR) with high performance oxygen reduction by using a simple heat treatment process. These catalysts were fabricated by directly calcining the Fe and/or Co doped polyaniline (PANI)-polypyrrole (PPYR) composites. Their electrocatalytic activity for ORR both in acidic and in alkaline media was investigated by voltammetric techniques. Among the prepared catalysts, Co/PANI-PPYR presents the most positive ORR onset potential of 0.62 V (vs. SCE) in 0.5 mol/L H2SO4 solution or −0.09 V (vs. SCE) in 1 mol/L NaOH solution. In addition, the Co/PANI-PPYR catalyst shows the largest limiting-diffusion current density for ORR, which is 4.3 mA/cm2@0.2 V (vs. SCE) in acidic and 2.3 mA/cm2@−0.3 V (vs. SCE) in alkaline media. In acidic media, a four-electron reaction of ORR on the Co/PANI-PPYR and Fe/PANI-PPYR catalysts is more dominant than a two-electron reaction. In alkaline media, however, a four-electron and a two-electron mechanisms are co-present for the ORR on all the prepared catalysts. Co/PANI-PPYR catalyst also presents good electrocatalytic activity stability for ORR both in acidic and in alkaline media.

The electrochemical performance of pitch coke anodes containing hollow carbon nanostructures and nickel nanoparticles for high-power lithium ion batteries

Pitch cokes with abundant hollow carbon nanostructures (HCNs) and nickel nanoparticles were prepared from pitch containing nickel nanoparticles by simple heat-treatment process. The effects of nickel content and heat-treatment temperatures on the electrochemical properties were analyzed systematically. Two kinds of pitch cokes were studied in detail and both of them revealed excellent electrochemical performances, such as high reversible capacity, excellent rate capability and good cycling properties that the capacity becoming bigger with cycling. The microstructure of the samples was characterized by X-ray diffraction and transmission electron microscopy. Combined with the electrochemical performances, it was assumed that the HCNs should play an important role in the enhancing electrochemical properties as the reservoir for the lithium storage and transfer. A sample composed mainly of HCNs was fabricated to verify the hypothesis.

Conversion of Industrial Bio-Waste into Useful Nanomaterials

Chromium-complexed collagen is generated as waste during processing of skin into leather. Here, we report a simple heat treatment process to convert this hazardous industrial waste into core–shell chromium–carbon nanomaterials having a chromium-based nanoparticle core encapsulated by partially graphitized nanocarbon layers that are self-doped with oxygen and nitrogen functionalities. We demonstrate that these core–shell nanomaterials can be potentially utilized in electromagnetic interference (EMI) shielding application or as a catalyst in aza-Michael addition reaction. The results show the ability to convert industrial bio-waste into useful nanomaterials, suggesting new scalable and simple approaches to improve environmental sustainability in industrial processes.

Fabrication of titanium based MALDI bacterial chips for rapid, sensitive and direct analysis of pathogenic bacteria

For the first time, we report the fabrication of a titanium bacterial chip for MALDI-MS produced from a simple, cost effective and rapid heat treatment process. This bacterial chip can be reused many times and is highly versatile. These bacterial chips serve dual roles: (1) They can be applied as MALDI-MS target plates for direct and highly sensitive bacterial analysis. (2) They can be used as bacterial sensors for direct analysis of the captured bacteria using MALDI-MS. The sensitivity of these chips when used as bacterial sensors is <103cfu/mL. The lowest detectable concentration for direct MALDI-MS analysis was found to be 104cfu/mL. The results were further justified by using standard plate counting method combined with Tukey–Kramer statistical analysis and fluorescence imaging followed by image processing for fluorescence quantification using ImageJ software to substantiate the MALDI-MS results.

Characterization and biostability of HA/Ti6Al4V ACL anchor prepared by simple heat-treatment

Here, we report a simple heat-treatment process to prepare hydroxyapatite (HA)-coated Ti6Al4V anterior cruciate ligament (ACL) anchor that has good hard tissue compatibility and biostability. Heat treatment was carried out for 1.5h at temperature range of 700–900°C. Morphological characterization showed rougher surface and larger pore spaces as the heat treatment temperature was increased. The Ti6Al4V heat-treated at 800°C had the highest diffused titanium phosphide formation, thus making it high in biocompatibility. For in vivo test, the most bone integration ability was obtained for heat-treatment at 800 and 900°C. Furthermore, the HA/Ti6Al4V ACL anchor heat-treated at 800°C had the highest amount of new bone formation. The present results suggest that an implant with complex shape like an ACL anchor could be prepared and used with an easy and low-cost technique by simple heat treatment surface modification method after dip-coating with HA.

Synthesis and characterization of in situ Fe2O3-coated FeF3 cathode materials for rechargeable lithium batteries

Here, a novel architecture of a core–shell structured FeF3@Fe2O3 composite with particle size of 100–150 nm and tunable Fe2O3 content is synthesized by a simple heat treatment process utilizing FeF3 with fine network structure as precursor. The structure, morphology and electrochemical performance of the pristine FeF3 and the FeF3@Fe2O3 composites are studied by XRD, SEM, TEM and discharge–charge measurements. XRD results show that the Bragg peaks of the FeF3@Fe2O3 composites are well indexed to FeF3 and Fe2O3. SEM and TEM images reveal the core–shell structure of the composites. The comparison of the electrochemical performance between the pristine FeF3 and the FeF3@Fe2O3 composites reveals that the in situ Fe2O3 coating (even with small amount, 0.6–5.2 wt%) has great influence on the improvement of electrochemical performance.

Porous Y2O3 microcubes: synthesis and characterization

In this work, a facile route using a simple solvothermal reaction and sequential heat treatment process to prepare porous Y2O3 microcubes is presented. The as-synthesized products were characterized by X-ray powder diffraction (XRD), scanning electronic microscope (SEM), energy dispersive spectrometer (EDS), thermogravimetric analysis (TG), and differential thermal analysis (DTA). The thermal decomposition process of the Y2O3 precursor was investigated. SEM results demonstrated that the as-prepared porous Y2O3 microcubes were with an average width of about 20 μm and thickness of about 8 μm. It was found that the morphology of the Y2O3 precursor could be readily tuned by varying the molar ratio of S2O82− to Y3+. Y2O3:Eu3+ (6.6%) microcubes were also prepared and their photoluminescence properties were investigated.

Synthesis and structure of [C 6N 4H 20] 0.5[B 5O 6(OH) 4]: A new organically templated pentaborate with white-light-emission

A new organically templated pentaborate [C 6N 4H 20] 0.5[B 5O 6(OH) 4] ( 1a) was prepared by reactions of triethylenetetramine (TETA) with excess boric acid in aqueous solution and characterized by elemental analysis, FTIR, TG-DTA, powder X-ray diffraction and photoluminescence spectroscopy. The structure of 1a was determined by a single-crystal X-ray diffraction. It crystallizes in the monoclinic system with space group P2(1)/ c, a=9200(3) Å, b=14.121(5) Å, c=10.330(4) Å, β=91.512(4)°, V=1341.4(9) Å 3, and Z=4. The luminescent properties of the compound were studied, and a green–blue luminescence occurs with an emission maximum at 507 nm upon excitation at 430 nm. The photoluminescence of 1a can be modified from green–blue to white by means of a simple heat-treatment process. The white-light-emission of sample 1c makes the pentaborate a good candidate for display and lighting applications in the white LED.

A novel method to synthesize cobalt oxide (Co3O4) nanowires from cobalt (Co) nanobowls

AbstractA novel method suitable for the synthesis of the cobalt oxide (Co3O4) nanowires at targeted regions is presented in this report. Cobalt (Co) nanobowls synthesized by colloidal crystal directed assembly were transformed into Co3O4 nanowires by a simple heat treatment process. Co nanobowls exhibited a two phase (h.c.p. + f.c.c.) microstructure while single phase microstructure was observed for Co3O4 nanowires. Ferromagnetic Co nanobowls showed a dependence of coercivity on bowl size while Co3O4 exhibited weak ferromagnetic behavior.

Nanoscale positioning of inorganic nanoparticles using biological ferritin arrays fabricated by dip‐pen nanolithography

In this manuscript we demonstrate the spatially controlled immobilization of ferritin proteins by directly writing them on a wide range of substrates of technological interest. Optical and fluorescence microscopy, AFM and TOF-SIMS studies confirm the successful deposition of the protein on those surfaces. Control on nanostructure shape and size, by miniaturizing the dot-like features down to a 100 nm, demonstrates the particular capabilities of the DPN approach. Ultimately, this study gives the opportunity to design nanoparticle-based arrays regarding the growing interest in the use of nanoparticles as structural and functional elements for fabricating nanodevices. Herein, we demonstrate how the protein shell of ferritins can be removed by a simple heat-treatment process while maintaining the encapsulated inorganic nanoparticle intact on the same location of the nanoarray. As a result, this study establishes how direct-write DPN approach could give the opportunity to design not only protein-based nanoarrays but also nanoparticle-based nanoarrays with high-resolution and control.

異なる初期組成粉末を用いた Bi2212 超伝導丸線材の組織観察

Bi2212 round wires are one of candidates for application in high magnetic fields and low temperatures because of its high performance of Jc. Furthermore, round wires are suitable to make complicated coils and Rutherford cables. Bi2212 round wires are fabricated by simple heat treatment process of partial melting and slow cooling. However, the Jc values are sensitive to reaction temperatures, especially maximum reaction temperature (Tmax). In this research, we fabricated Bi2212 round wires with different compositions. We prepared four powders with the nominal compositions of between Bi=2.00 and Bi=2.25. Highest Ic value of 260 A (Jc=200 A/cm2) at 4.2 K and 10 T were obtained in Bi2.25 sample with Bi rich composition. From the observations of microstructures, we observed small amount of bridging of filaments in high Ic sample. To understand the growth mechanism of bridging, we report the results of quench experiments during heat processing.

이온성 고분자 금속 복합물(IPMC) 액추에이터의 열처리에 의한 성형 및 특성분석

Ionic polymer metal composite(IPMC) has been used as a promising material for various actuator applications. The IPMC actuator is difficult to be fabricated with complicated 3-dimensional shape. We propose a simple heat treatment process that can fabricate IPMC actuator with various shapes. Experimental results show the pre-shaped IPMC actuator by heat treatment does not show any degradation of its actuation abilities such as bending displacement, generation force and reliability in bending motion.

Large scale synthesis of N-doped multi-layered graphene sheets by simple arc-discharge method

N-doped multi-layered graphene sheets were synthesized in large scale by the method of direct current arc-discharge between pure graphite rods. For the use of NH 3 as one of the buffer gas, the multi-layered graphene sheets were doped with N without the addition of other nitrogen source. The product so obtained has been characterized by transmission electron microscopy, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and element analysis. The graphene sheets are mainly of 2–6 layers and their sizes are about 100–200 nm. The multi-layered graphene sheets can be purified by a simple heat treatment process. The content of N atoms on the multi-layered graphene sheets can be tuned by simply changing the proportion of NH 3 in the atmosphere.

A White‐Light‐Emitting Borate‐Based Inorganic–Organic Hybrid Open Framework

Intrinsic white borate phosphors: Solvothermal reaction of H3BO3 and ethylenediamine afforded the first three-dimensional zeolite-like ammonium borate. Its blue photoluminescence can be modified to white by a simple heat-treatment process at 250, at 360, or at 250 °C after doping with Eu3+ ions (see picture, left to right). In the absence of solvent, the same solvothermal reaction gave the first amine-pillared layer borate-based framework.

A simple one-step heat treatment process for preparing biaxially textured buffer layers on rolled Ni tape for high Tc coated conductors’ application

Fabrication of YBCO films on metal tapes by a full solution method is a promising technique for industrial application. For this process, the fabrication of suitably textured buffer layers is very important. In this paper, we report a new simple one-step heat treatment process, namely by the simultaneous texture (STEX) technique, for formation of textured buffer layers on cold rolled Ni tape by a sol–gel method. CeO 2 and Ba 0.5Sr 0.5TiO 3 (BST) buffer layers have been prepared using this new process. X-ray diffraction analyses show that the buffer layers are highly c-axis oriented. The FWHM values for ω and ϕ scans of the CeO 2 films are 4.09° (Ni: 4.77°) and 6.04° (Ni: 5.63°). The FWHM values for ω and ϕ scans of BST films are 8.01° (Ni: 7.78°) and 8.55° (Ni: 7.16°). A {1 0 0}〈0 0 1〉-cube texture was also formed in the rolled Ni substrate during the STEX process, indicating cube-on-cube texture formation by only a one-step annealing treatment. The possible mechanisms relating to cube-on-cube texture formation by a one-step annealing treatment are discussed.

Using phenol–formaldehyde resin as carbon source to synthesize mesoporous carbons of different pore structures

In this research communication, we performed the phenol–formaldehyde (PF) resin as an alternative carbon source and various mesostructured silicas as the nano-templates to conveniently prepare the mesoporous carbons of high surface area (850–1500 m 2 g −1), large pore size (2.0–22.0 nm) and great pore volume (0.65–1.15 cm 3 g −1). It was reasonably supposed that there exist interaction matching between the negative-charged silica surface of the silica template and PF resin. Therefore, the PF oligomers could be homogeneously adsorbed into the nanochannels or cages of the mesoporous silicas via an impregnation process. Because the thermosetting PF resin only requires a simple heat treatment process at 100 °C to form the cross-linked polymeric structure, the replication of the mesostructure of the mesoporous silica template could be readily achieved without adding any polymerization catalysts.

An amorphous hydrocarbon diamond-like polymer as a precursor for diamond growth

A diamond-like polymer, poly(phenylcarbyne), was synthesized by reductive condensation of α,α,α-tricholorotoluene monomer with an ultrasonically-generated NaK alloy emulsion in tetrahydrofuran under an inert atmosphere. The polymer consists of a randomly constructed rigid network of tetrahedral polycarbyne units in which each carbyne carbon forms three CC bonds to the network and one to a substituent structure of the polymer, which was analyzed by nuclear magnetic resonance (NMR), X-ray photospectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The polymer is easily soluble in organic solvents to form a solution which can be applied to various substrates and forms films with a large area. By a simple heat-treatment process, this amorphous polymer can transform into diamond crystals at relatively low temperature (600°C), and the structure of the diamond crystals was confirmed by micro-Raman spectroscopy. The correlation of thermal gravimetric analysis (TGA) and differential thermal analysis (DTA), FTIR and Raman spectra of polymers provides important information on the process of phase transformation.