Nm For Samples Research Articles

Using of asymmetric cell to monitor corrosion performance of 304 austenitic stainless steel by electrochemical noise method

In this study, corrosion of 304 Austenitic stainless steel (ASS) with varies oxide layers, developed at two temperatures, is investigated by an asymmetric (Asy) cells in 0.05 M FeCl3 solution with time. Therefore, the Asy electrodes system is introduced to perform valuable data. Electrochemical current noise (ECN) signals resulting from the Asy cells are elucidated using the standard deviation of partial signals (SDPS) plot, the recurrence plot (RP), and the statistical procedure which derived from wavelet transform (WT) along with electrochemical impedance spectroscopy (EIS). The Asy electrodes indicated a high advantage and improved the detection of intergranular corrosion (IGC) on the 304 ASS alloy compared with the symmetric (Sym) ones. The trend of signals is eliminated, and then the disintegration of every signal is also performed into 10 crystals. Afterward, the standard deviation of every crystal is shown with the SDPS plots. Besides, ECN signals related to dissimilar crystal numbers are distinguished by the RP, based on the signals population. According to EIS measurements, the thickness of passive oxide layer of sample heated at 0–700 °C is decreased from 57 to 33 nm with immersion time, while it is increased from 9 to 27 nm for sample heated at 1100-700 °C.

Preparation of novel B4C nanostructure/Si photodetectors by laser ablation in liquid

In this study, boron carbide (B4C) nanoparticles (NPs) are synthesized by pulsed laser ablation of boron in ethanol at a laser fluence of 6.36 J cm−2 pulse−1. The effect of numbers of laser pulses on the structural, optical, and electrical properties of B4C NPs was studied. X-ray diffraction (XRD) results revealed that all B4C nanoparticles synthesized were polycrystalline in nature with a rhombohedral structure. When the laser pulses increased from 500 to 1500, the optical band gap of B4C decreased from 2.45 to 2.38 eV. Fluorescence measurements showed the emission of two emission peaks. The Raman spectra of B4C nanoparticles exhibit six vibration modes centered at 270, 480, 533, 722, 820, and 1080 cm−1. Field emission scanning electron microscope (FESEM) images show the formation of spherical nanoparticles of an average size of 68, 75, and 84 nm for samples prepared at 500, 1000, and 1500 pulses, respectively. The dark I–V characteristics of B4C/Si heterojunction photodetectors showed rectification characteristics, and the heterojunction prepared at 500 pulses exhibits the best junction characteristics. The illuminated I–V characteristics of B4C/p-Si heterojunction photodetectors exhibited high photosensitivity to white light. The spectral responsivity of the p-B4C/p-Si photodetector shows that the maximum responsivity was 0.66 A W−1 at 500 nm for a photodetector prepared at 500 pulses. The highest specific detectivity and quantum efficiency were 2.18 × 1012 Jones and 1.64 × 102% at 550 nm, respectively, for a heterojunction photodetector fabricated at 500 pulses, The ON/OFF ratio, rise time, and fall time are measured as a function of the number of laser pulses. The photodetector fabricated at 1500 laser pulses showed roughly rise and fall intervals of 1.5 and 0.8 s, respectively.

Preparation and Characterization of Organic Inorganic Hybrid MAPbI2Br Perovskite

In this work, perovskite compounds were prepared and studied by using chemical methods for methyl ammonium halide MABr and lead halide PbI2. The main objective of the study is to successfully prepare new types of perovskites using the one-step method by changing the weight ratios of lead halide PbI2 in a fixed weight ratio of methyl ammonium bromide MABr, where they were classified into samples P1 which represents MABr/PbI2 weight ratios (0.22:0.39)g, P4 which represents MABr/PbI2 weight ratios (0.22:0.59)g and P7 which represents MABr/PbI2 weight ratios (0.22:0.79)g and the impact of this change was studied. High crystallinity was obtained in the crystal structure of the P4 sample after increasing the weight ratio of lead halide from 0.39 g to 0.59 g. Then the crystallization decreased and the crystal structure changed after increasing the weight ratio from 0.59 g to 0.79 g in the sample P7. The increase in PbI2 weight from 0.39 g to 0.59 g and 0.79 g affected the absorption edge and shifted widely towards long wavelengths (red shift) from 625 nm to 691 nm and 805 nm. The energy band gap changed from 1.98 eV to 1.79 eV and to 1.53 eV. The study showed that the surface morphology of these samples, where a sample with a homogeneous film with a high density was obtained, resulted from an increase in the weight of lead halide from 0.39 g to 0.59 g and with small Nano-diameters of 34.25 nm for the P4 sample. After increasing the weight from 0.59 g to 0.79 g, a sample was obtained with a less dense membrane that contains many voids and a semi-micro large particle diameter is 97.32 nm for the sample P7. Finally, the sample P4 was selected with good crystalline and optical properties and a homogeneous surface formation with a high density that could enter into the special composition for the manufacture of optical devices with high efficiency and stability.

Effect of Sensitive pH on Hydroxyapatite Properties Synthesized from Chicken Eggshell

The hydrothermal method has effectively synthesized hydroxyapatite (HA). This study aimed to analyze the effect of pH on the properties (purity, crystallinity, and size) of HA crystals. HA synthesis of chicken eggshells was carried out using the hydrothermal method at temperatures of 230 °C with pH 9 and 9.34. The characteristics of HA are determined by XRF, XRD, FTIR, and TEM. The composition of the most significant compound obtained from the results of XRF analysis is CaO (97.5%). The XRD analysis showed that the purity of HA with pH 9.00 and 9.34 obtained was 97.8 and 96.6%, with the crystallinity of 56.46 and 56.96%. It was also obtained that the size of crystal HA was 21.8 and 15.7 nm for samples synthesized at pH 9.00 and 9.34. The results showed that the purity and size of HA were affected by differences in the pH synthesis and were relatively the same for its crystallinity which directly affects the value lattice parameter. The properties of HA produced by the hydrothermal method have met the criteria for biomedical applications.

THE EFFECT OF LASER ENERGY DENSITY ON THE PROPERTIES OF GRAPHENE DOTS

The structural and optical properties of dots based on graphene oxide (GO) obtained by laser ablation method with various energy densities of radiation were studied. It was shown that after laser ablation, the average lateral size of GO sheets was decreased from 1280–1900 nm to 230±95 nm and 110±42 nm for samples prepared at a laser radiation with energy density of E~15 and 21 mJ/cm2, respectively. Raman spectroscopy datashowed that after ablation, the ID/IGratio decreased from 1.04 to 0.97, indicating an increase in the number of sp2-hybridized domains in GO after ablation. A change in the energy density has practically no effect on a change in its functionalization, aswell as the ordering of sp2domains inside a GO sheet. The optical density of GO dispersions and the intensity of their fluorescence depend on the ablation conditions. For non-ablated dispersions along with the luminescence band at 450 nm, additional bandappears in the spectrum with a maximum at about 600 nm. After ablation the distribution of particles becomes more uniform, as evidenced by both the change in the shape of the GO luminescence band and the constancy of the fluorescence lifetime upon registration at different wavelength.

Enhanced optical transmittance of silver nanowires via gamma rays irradiation

Metallic nanowires (MNWs) are of particular interest as transparent electrodes (TEs) in optoelectronic devices due to their outstanding and unique optical, electrical and mechanical capabilities. In present research, we systematically studied the influence of gamma radiations (γ-radiations) on silver nanowires (AgNWs). We irradiated AgNWs with various doses of γ-radiations ranging between 12 kGy and 20 kGy. After irradiation, we studied the structural properties of un-irradiated and γ-irradiated AgNWs via X-ray diffraction (XRD). The XRD analysis of un-irradiated sample confirmed the pure crystalline metallic nature of un-irradiated AgNWs with crystallite size 29.80 nm. The XRD analysis of irradiated samples revealed the face centered cubic (FCC) crystalline structure at all doses of γ-radiations. The crystallite sizes have been observed to be 31.99 nm, 33.94 nm and 32.56 nm for samples irradiated by γ-radiations of doses 12 kGy, 15 kGy and 20 kGy respectively. XRD data was also used to investigate structural factors such as dislocation density and strain in material. Morphological studies were carried out via transmission electron microscopy (TEM). The TEM images revealed that silver nanoparticles (AgNPs) are formed on outer surfaces of AgNWs after γ-irradiation. After γ-irradiation, optical transmittances have been enhanced up to dose 15 kGy which is might be due to formation of NPs on Ag-NWs.

Structural and Optical Properties of ZnO Nanostructures Synthesized by Hydrothermal Method at Different Conditions

ZnO nanostructures were synthesized by hydrothermal method at different temperatures and growth times. The effect of increasing the temperature on structural and optical properties of ZnO were analyzed and discussed. The prepared ZnO nanostructures were characterized by X-ray diffraction (XRD), UV–Vis. absorption spectroscopy (UV–Vis.), Photoluminescence (PL), and scanning electron microscopy (SEM). In this work, hexagonal crystal structure prepared ZnO nanostructures was observed using X-ray diffraction (XRD) and the average crystallite size equal 14.7 and 23.8 nm for samples synthesized at growth time 7 and 8 hours respectively. A nanotubes-shaped surface morphology was found using scanning electron microscopy (SEM). The optical properties showed that the samples had good absorbance in the UV-Vis. region and wide band gap. The PL spectrum displayed that the intensity of ultraviolet (UV), band gap and defect bands depend on the growth temperature of the ZnO nanostructure. The largest band gap was 3.351 eV for ZnO nanostructure synthesized at 100 °C and growth time 8h.

Pt nanoparticles synthesized by successive ionic layers deposition method and their electrocatalytic properties in hydrogen evolution reaction during water splitting in the acidic medium

The paper explores the possibilities of the successive ionic layers deposition (SILD) nanotechnology for Pt nanoparticle synthesis. It is shown that the SILD nanotechnology, which is based on successive treatment of appropriate substrates in solutions of a platinum complex compound and a reducing agent, is effective for controlled Pt0 nanoparticles formation on the substrate surface. The Pt nanoparticles synthesized using Na2PtCl6 and NaBH4 precursors are characterized. It is found that the concentration and size of the Pt0 nanoparticles deposited on the titanium foil surface can be controlled by the number of deposition cycles. It is established that the size of the Pt nanoparticles depends on the synthesis conditions and varies from 3.3 nm to 10.0 nm for samples synthesized as a result of 10–40 SILD cycles. A model explaining Pt nanoparticle growth during SILD is suggested. It is shown that the nanoparticles obtained exhibit electrocatalytic properties in the hydrogen evolution reaction during acidic water electrolysis. In a series of samples synthesized using 10–40 SILD cycles, the best electrochemical characteristics are demonstrated by the sample obtained after 20 deposition cycles: its overpotential value is 44 mV and the Tafel slope is 30.4 mV/dec.

Taking a different road: following Ag25 and Au25 cluster activation via in situ differential pair distribution function analysis.

Synchrotron X-ray total scattering measurements and accompanying pair distribution function (PDF) analyses are an excellent characterization technique to complement both transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy methods for detailed structural studies of atom-precise metal clusters. Herein, we study the thermal activation of Au25(SR)18- and Ag25(SR)18- clusters on alumina supports via in situ differential PDF (dPDF) analyses to compare structural changes in the metal clusters upon thermal activation in air. The metal-metal interatomic distances in Au25(SR)18- and Ag25(SR)18- clusters as measured by the dPDF method are comparable with those measured via single-crystal crystallographic and EXAFS methods. Compared to EXAFS analysis, in situ dPDF data can also provide high-temperature, non-element specific, longer range structural information with excellent temporal resolution. TEM and dPDF results show that Ag25(SR)18 systems behave significantly differently than analogous Au25(SR)18 systems upon thermal activation. Atom-precise Au clusters on alumina supports show continuous growth in particle size with increasing activation temperature due to particle coalescence upon thermal deprotection, and grow to an average size of 11.2 ± 2.1 nm for samples thermally activated at 650 °C. Conversely, analogous Ag clusters on alumina supports show particle size growth to mid-sized particles (3.2 ± 0.4 nm) at activation temperatures of 450 °C, beyond which the Ag particles then undergo thermal degradation to give smaller Ag clusters with an average size of 1.4 ± 0.2 nm for samples thermally activated at 650 °C. The significant difference in the behaviours of atom-precise, thiolate-protected Au and Ag clusters upon thermal activation emphasizes the development of distinct activation protocols for different metal cluster systems.

Влияние лазерной обработки на структуру и спектрально-люминисцентные свойства графеновых точек

The structure and optical properties of nanodots based on graphene oxide (GO) obtained by ablation by laser radiation with different wavelengths were studied. It was shown that after laser ablation, the average lateral size of GO sheets decreases from 820±120 nm to 204±40 nm and 105±23 nm for samples prepared at λgen=355 and 532 nm, respectively. In this case, a change in the intensities of the 2D and G bands was observed, which indicates a decrease in the number of layers in the GO sheets. The optical density of GO dispersions and the intensity of fluorescence depend on the ablation conditions. After ablation, the optical density of GO increased by ~13% for samples obtained at λgen=355 nm and by 20% for λgen=532 nm. The fluorescence intensity of GO ablated at λgen=532 nm increased by 57% relative to the value registered for GO before ablation. For 355 nm, the fluorescence intensity was changed by 7%.

Effect of laser treatment on the Structure and Spectral-Luminescent Properties of Graphene Dots

The structure and optical properties of nanodots based on graphene oxide (GO) obtained by ablation by laser radiation with different wavelengths were studied. It was shown that after laser ablation, the average lateral size of GO sheets decreases from 820±120 nm to 204± 40 nm and 105± 23 nm for samples prepared at λgen=355 and 532 nm, respectively. In this case, a change in the intensities of the 2D and G bands was observed, which indicates a decrease in the number of layers in the GO sheets. The optical density of GO dispersions and the intensity of fluorescence depend on the ablation conditions. After ablation, the optical density of GO increased by ~ 13% for samples obtained at λgen=355 nm and by 20% for λgen=532 nm. The fluorescence intensity of GO ablated at λgen=532 nm increased by 57% relative to the value registered for GO before ablation. For 355 nm, the fluorescence intensity was changed by 7%. Keywords: graphene oxide, graphene dots, ablation, structure, optical properties.

Molecularly Engineered Aptamers Targeting Tumor Tissue and Cancer Cells for Efficient in Vivo Recognition and Enrichment

Molecularly Engineered Aptamers Targeting Tumor Tissue and Cancer Cells for Efficient in Vivo Recognition and Enrichment

Влияние структурных изменений нанокристаллов на механические свойства HPHT спеченного детонационного наноалмаза

The paper presents the results of studies on mechanical and structural properties of detonation nanodiamonds obtained by HPHT (high-pressure high-temperature) annealing within a wide temperature range. The experiments were carried out using a high-pressure “split-sphere” type apparatus (BARS) under 5 GPa and at 1100 –1500°С. It is established that the thermobaric treatment allows the production of strong composites with the local hardness up to 15 GPa. It is shown that the average value of microhardness increases with the sintering temperature. The temperature increase from 1100 to 1500°С results in an enhancement of the average value of microhardness from 8.8 to 12.2 GPa. The obtained materials are structurally inhomogeneous, regions of higher hardness are located in the central part of the samples. However, when the sintering temperature increases, dispersion of the microhardness decreases from 6.4 to 1.4 GPa which is caused by an improvement of the structural homogeneity of the composite with an increase in temperature. The thermobaric effect results in the growth of cores of diamond nanocrystals from 4.2 to 6.9 nm in samples obtained at 1500°С. It is highly probable that this growth occurs as a result of embedding of non-diamond phase carbon into the diamond core lattice during thermobaric sintering. This conclusion is made on the basis of X-ray data analysis. The specific feature of transformation of detonation nanodiamond shells consists in a simultaneous occurrence of two processes — desorption of volatile impure compounds and formation of a newly-formed diamond phase or ordered graphite around diamond cores. This effect results in the formation of open fragments of diamond cores capable of contacting with neighboring nanodiamond crystals thus binding diamond grains into a composite. Sintering temperature is an essential factor that affects the nanocrystal size as well as the mechanical properties and homogeneity of the composite.

Synthesis of ZIF-67- Effect of solvent on the structure

In the present paper, ZIF-67 material was synthesized from cobalt (II) nitrate hexahydrate and 2-methyl imidazole in three different solvents (methanol, ethanol and acetone) at room temperature. The obtained samples were characterized using XRD, SEM, FTIR, TGA and nitrogen adsorption/desorption measurements. The results show that the synthesized ZIF-67 materials had a high purity, nano-size, and uniformity with the sharp dodecahedrons structure of ZIF-67. Solvents had an influence on the size and nature of the ZIF-67 crystal. The average crystalline size of the nanoparticles calculated by Scherrer equation were 64 nm for sample in acetone solvent, 128 nm for sample in ethanol solvent and 132 nm for sample in methanol solvent. The obtained samples had high thermal stability ( 320 °C). The ZIF-67 material with ethanol solvent had a high specific surface area (SBET) of 1506 m2/g. The synthesized samples exhibited better adsorption capacity of methyl oranges than that of rhodamine B.

Synthesis of ZIF-11- effect of source of zinc salts on the structure

In this paper, ZIF-11 material was synthesized from benzimidazole and different zinc salt sources at room temperature. The obtained samples were characterized using XRD, SEM, FTIR and TGA measurements. The results showed that the synthesized materials had nano-size, and uniformity with the sharp dodecahedrons structure of ZIF-11. Zinc sources had an influence on the size and nature of the ZIF-11 crystal. The average crystalline size of the nanoparticles calculated by Scherrer equation were 85.5 nm for sample of zinc nitrate, 91.9 nm for sample of zinc chloride and 111.5 nm for sample of zinc acetate. The obtained samples had high thermal stability ( 460 °C). The adsorption capacity of the synthesized materials for iodine from aqueous solution was very high (236 mg/g).

Densification, microstructure and optical properties of YAG transparent ceramics prepared by dry-pressing and gelcasting

The effects of dry-pressing and gelcasting on the densification, microstructure and optical properties of YAG transparent ceramics were researched. The gelcasting samples had smoother and more uniform surface without agglomeration, but its average pore size was larger than that of the dry-pressing samples. The dynamic densification curves showed three continuous transition stages. The initial temperature of densification for the gelcasting samples was higher than that for the dry-pressing samples, but the initial temperature of obvious grain growth for the gelcasting samples were relatively lower. After being sintered at 1750 °C for 10 h, the transmittances at 1064 nm of samples (thickness of 1 mm) prepared by dry-pressing and gelcasting were about 77.79% and 81.26%, respectively. These two forming methods had difference influences on the microstructure, the dynamic shrinkage curves and the microstructure evolution of green bodies or ceramics, which could further impact the properties of YAG transparent ceramics. In a word, the gelcasting had certain advantages over the dry-pressing in preparing YAG transparent ceramics.

Yb3+ influence on NIR emission from Pr3+-doped spherical yttria nanoparticles for advances in NIR I and NIR II biological windows

Highly intense NIR emissions in the first and second biological windows and a remarkable UV–Vis and NIR to NIR energy conversion were observed for Pr3+, Yb3+ co-doped yttria nanoparticles, synthesized via the homogeneous precipitation method. A single-phase body center cubic Y2O3 structure was formed for all the samples after annealing 900 °C for 2 h. Increasing the dopants content, from 0.5 to 5.0 mol %, the replacement of Y3+ by Pr3+ and Yb3+ ions lead to a lattice expansion, which could be calculated. Spherical monodispersed nanoparticles, constituted of several crystallites, were observed by TEM and SEM images. The particles size ranged from 143 to 272 nm for the as-prepared samples and from 88 to 202 nm for the samples annealed at 900 °C. The crystallite size was estimated by Debye-Scherrer and Williamson-Hall methods and ranged from 6 to 27 nm with an average of 13 nm. Photoluminescent studies evidenced pronounced Pr3+ and Yb3+ near infrared (NIR) emission under ultraviolet, visible, and NIR excitation. How the Yb3+ ions co-doping, as well as, the total rare earth content, affected the luminescence properties, were evaluated, along with the energy transfer process involving UV–Vis and NIR to NIR energy conversion between the doping ions and the host. The energy was transferred between the Y2O3 host and Pr3+, Yb3+ upon CT band excitation at 290 nm. NIR emission at 948, 1080, 1115 nm, and 1.5 μm attributed to the Pr3+ transitions 3P0,1→1G4, 1D2→3F3, 1D2→3F4, and 1D2→1G4, denoting the 1D2 population through a multiphonon relaxation process (3P0+3H4→3H6+1D2). A concentration quenching process was ascertained in the highest concentration of dopants (5.0 mol % in total), which indicated that cross-relaxation took place. Both the Yb3+-doped and Pr3+, Yb3+ co-doped samples presented the Yb3+ emission 2F5/2→2F7/2 at 976 nm. All the structural, morphological, and spectroscopic properties of the materials make these spherical yttria nanoparticles potential NIR emitting probes candidates for advances in biophotonics, especially for deep-tissue imaging using NIR I and NIR II biological windows.

Synthesis and photoluminescence properties of fluorine‐containing poly(phenylene vinylene) bearing hexafluorocyclopentene‐fused phenanthrene unit

AbstractThe intramolecular oxidative photocyclization of 1,2‐diarylhexafluorocyclopentene (1) under light irradiation (λ = 365 nm) provided hexafluorocyclopentene‐fused phenanthrene with formyl groups (2) in moderate yield. The copolymerization of 2 with tetraethyl(2,5‐bis(dodecyloxy)‐1,4‐phenylene)bis(methylene)diphosphonate by the Horner–Wadsworth–Emmons reaction gave a fluorine‐containing poly(phenylene vinylene), Polymer‐2, in 41% yield. For comparison, a diphenylethene‐type copolymer, Polymer‐1, was also prepared analogously. The number‐average molecular weights of Polymer‐1 and Polymer‐2 were 8900 and 3300 g mol−1, respectively. The copolymers showed high thermal stability, as revealed by their thermogravimetric analysis. UV–visible spectra of the copolymers in CHCl3 showed π–π* transition peaks at around 420 nm, and the peaks shifted to longer wavelengths by ca 10 nm for samples in film form. The photoluminescence spectra of Polymer‐1 and Polymer‐2 exhibited peaks at 542 and 560 nm in CHCl3, respectively, whereas the photoluminescence intensity of Polymer‐2 was very low in the solid state, presumably owing to the partial aggregation of the polymer molecules. © 2021 Society of Industrial Chemistry.

Microstructure and Performance of Ni-Free Nano La0.75Sr0.25Cr0.5Mn0.5O3 - Gd0.2Ce0.8Ox Composite Anode

Degradation of conventional solid oxide fuel cell (SOFC) anode is often associated with nickel coarsening and redox instability. Great efforts have been made to find alternative materials to replace the state-of-the-art nickel - yttria-stabilized zirconia (Ni-YSZ) anode cermet. In the previous study, La0.9Sr0.1Cr0.5Mn0.5O3-Gd0.1Ce0.9Ox (LSCM-GDC) composite anode was investigated as one of the possible alternatives for Ni-free SOFC (1). The LSCM-GDC composite was fabricate by mixing commercial powders in the designated proportion. It was shown that the surface area of GDC has to be increased and the grain size has to be decreased in order to compensate for the poor electrocatalytic properties.In this study, the microstructure and electrochemical performance of Ni-free anode fabricated with La0.75Sr0.25Cr0.5Mn0.5O3 : Gd0.2Ce0.8Ox = 50 : 50 w.% (LSCM-GDC) nano-powder are investigated. The LSCM-GDC nano-composite particles were prepared through colloidal-processing-based approach (2). The growth of homogenous nano-particles is induced by the heterogeneous nucleation of a LSCM precursor on the surface of GDC nanocrystals. The nucleation is further followed by heat treatment at 1000 oC to convert precursors into oxides. The resulting nano-powder consists of well dispersed LSCM and GDC nano-particles with the size of approximately 50 nm.The electrolyte-supported SOFC cells are fabricated by screen-printing LSCM-GDC anode and pure LSCM current collector on the surface of YSZ pellet. The cathode is fabricated on the opposite of the YSZ pellet by screen-printing GDC blocking layer and LSCF electrode. The effects of sintering temperature (1100oC and 1200oC) and LSCM-GDC anode thickness are investigated. The characterization of the cells is conducted by a series of electrochemical impedance spectroscopy (EIS) measurements at 800 – 500 oC. The high resolution focused ion beam - scanning electron microscopy (FIB-SEM) is used to evaluate 3-D microstructures of the anodes sintered at 1100 oC and at 1200 oC.The microstructures of samples are shown in Fig. 1. The well dispersed 50 nm LSCM and GDC particles moderate grain growth of the composite and result in fine microstructure. The GDC average intercept lengths are 80 and 134 nm for samples sintered at 1100 and 1200 oC, respectively.The polarization resistance strongly depends on the electrode thickness and sintering temperature. The higher sintering temperature induces grains coarsening and decreases the GDC surface area. Therefore, better performance is achieved for samples sintered at 1100 oC than at 1200 oC. The best performance of 0.14 Ω cm-2 (measured at 800 oC with H2 : H2O : N2 = 40 : 20 : 40 %) is achieved for the thinnest LSCM-GDC-1100oC electrode of 6 µm. Polarization resistance increased with the electrode thickness. This is attributed to the poor connectivity of the LSCM network. The connectivity of LSCM is lost in the range of 1.5 µm from the current collector layer for LSCM-GDC-1100oC, and the electron transport has to be maintained by GDC. Due to the relatively low electronic conductivity of GDC, the electrode thickness has to be limited.1. A. Sciazko, R. Yokoi, Y. Komatsu, T. Shimura, and N. Shikazono, ECS Trans., 91, 1711–1720 (2019).2. K. Sato, C. Iwata, N. Kannari, and H. Abe, J. Power Sources, 414, 502–508 (2019). Figure 1

Low-temperature solid-phase pyrolysis: A new method for the synthesis of nanocrystalline NiFe2O4 thin films

Nickel ferrite thin films were synthesized by a new method of solid-phase pyrolysis. The effect of the annealing temperature on the films characteristics has been studied. The obtained films were characterized by X-ray diffraction (XRD), thermal and thermogravimetric analysis (TG-DTA), and scanning probe microscopy (SPM). XRD showed a single-phase cubic spinel structure. The average size of NiFe2O4 crystallites was 28, 30, 42, and 53 nm for samples annealed at 500, 600, 700, and 800 °C, respectively. The films thickness is about 40 nm. The SPM data confirm a high-quality of the film surface, formed by nanocrystallites. The obtained films are well organized, which makes the proposed as a promising method of synthesis in the thin films preparation processes employed in a variety of applications.