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In this study, (1?x)(K0.5Bi0.5TiO3-BaTiO3)?xNa0.5Bi0.5TiO3 KBT:BT = 2:1 where x = 0.8 (KBT-BT-NBT) (001) textured lead-free piezoelectric ceramics were fabricated using BT template by templated grain growth with tape casting. Unlike the commonly used matrix preparation method, which is the calcination of all raw materials in one step, the matrix phase was prepared in a different way by first preparing KBT, BT and NBT powders separately and then by calcining the mixtures of these powders, so that effect of the matrix, synthesized by this alternative route, on texture development properties was evaluated. In addition, the effect of BT template content on the grain orientation with different sintering temperature and time, structure evolution, phase stability and piezoelectric properties were investigated to assess the materials’ actuating performance. The highest Lotgering factor of 81% was achieved for the textured ceramics with 10 wt% BT templates sintered at 1150 °C for 48 h. Compared to the one-step synthesis method, similar Lotgering factor values were obtained at lower sintering temperatures in the matrix, synthesized by the alternative 2-step method. The highest piezoelectric constant, remnant polarization, strain value and depolarization temperature were also obtained from the same sample, as ~ 190 pC/N, 30 kV/cm, 25% at 50 kV/cm and ~ 165 °C, respectively. The results show that the textured, lead free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 (KBT-BT-NBT) ceramics that are developed by using the matrix, synthesized by the alternative 2-step method, can be very promising lead-free electroceramics for high performance actuator applications. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature., 1709F504; Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK: 116M214, This work was supported by The Scientific and Technological Research Council of Turkey and Eskisehir Technical University Scientific Projects Commission (Grant Numbers 116M214 and 1709F504)

Chitosan exhibit great potential to be a critical part of the global sustainability solution; however, itsapplication areas are limited due to its inadequate properties for some applications. The use of chitosan islimited because of several reasons such as performance (brittleness, poor barrier properties) and processing (lowthermal strength temperatures). The properties of chitosan depend on its molecular weight and there are notenough studies in the literature. The application of nanoparticles to chitosan provides new advantages both inimproving the properties of chitosan and in reducing its costs. However, such nanoparticles can introduce somedifficulties. Nanoparticles additives increase transparency but cause agglomerates due to the highsurface/volume ratio, which reduces the local mechanical strength. Recently a novel particle technology, calledas MicNo®. MicNo® particles are designed micron size hexagonal plates which are composed of primary fineparticles. They only exhibit advantages of micron and nano size. For example, they exhibit superior surfacecoverage (up to 70% mole) with respect to spherical particles while they are transparent. Accordingly, theresearch goal of this study was to appraise effects of MicNo® and nano ZnO particles on structure developmentand hence properties of medium molecular weight Chitosan/PVA films. The results show that MicNo® particlesimprove UV-resistance and degree of crystallinity of the films and demonstrate great potential as newgeneration additive systems for biodegradable polymers to extend their application areas.

Conducting polymer composites (CPCs) are employed as antistatic coating materials where conductive fillers are dispersed in polymeric matrices. MicNo (=Micron+naNo) polygonal platelets are composed of nano-sized primary particles that exhibit both micron and nano size characteristics. In this study, the role of aluminum (Al) doping on physicochemical characteristics of MicNo-ZnO and the resultant effects on optoelectronic properties were investigated. Morever, the possibility of using such particles in CPC systems for antistatic coatings was also explored. It is shown that Al-doped powders lowers the bulk resistivity of polymers without inducing significant structural changes. For instance, powders with 0.3 mol% Al doping exhibits ≈40 KΩ.cm bulk resistivity which is two orders of magnitude lower than that of undoped sample. Addition of 10 wt% doped powder into epoxy resin reduces the resistivity from ≈6 MΩ.cm to ≈1.7 MΩ.cm. The results show that Al-doped MicNo powders are suitable for utilization in CPCs.

Titanium glycerolate precursors were prepared from a novel starting material and using glycerol as a chelating ligand and solvent via a developed method. This method and optimization of process parameters provided morphology control, and rod-like anatase particles with a high surface area and large aspect ratio were synthesized.

In the present study, ultrafiltration (UF) membranes were manufactured using different polymeric backbone materials such as polyvinyl chloride (PVC) and polysulfone (PSf) and modified with ZnO nanoparticles using a varying ratio of 0.1-2.0 wt.% in order to achieve the best filtration performance. Moreover, compositions of the casting solutions of the pristine membranes in terms of polymer/solvent and polymer/pore-former ratios were varied to determine the best pristine membrane recipe. The results showed that 0.5% ZnO loading provided the highest water flux performance for both PVC and PSf based membranes, which were found as 420 and 426 L/m(2)h, respectively, under the transmembrane pressure of 0.7 bar. Several characterization techniques were carried out to examine thermal and mechanical properties, as well as morphological structures in comparison to the pristine membranes. The type of polymeric backbone material exhibited a significant effect not only on the filtration performance but also on the lifetime and mechanical properties of the UF membranes. The results clearly indicate that the compatibility of ZnO nanoparticles with PVC is better than PSf under identical fabrication conditions.

SAVACI, UMUT/0000-0002-5801-9666; Dermenci, Kamil Burak/0000-0002-9439-6098, WOS: 000515086800001, ZnO-based anodes are currently possessing drawbacks such as their low cyclic stability, high capacity fade, and relatively low electronic conductivity that prevent their widespread use in commercial batteries. A commercially available, patented MicNo morphology of ZnO is known to adopt the advantages of nanosize into bulk in the field of semiconductor and cosmetic technology. in this study, the electrochemical performance of ZnO having MicNo morphology and its potential use in Li-ion batteries were investigated. After 100 galvanostatic cycles at constant 100 mA/g current density, the retained capacity of MicNo is higher than nanosized ZnO-the starting powder for MicNo ZnO. on the contrary, at higher current densities of 500 or 1000 mA/g, the nano-ZnO showed better cyclability and lower capacity fade compared to MicNo ZnO. in cyclic voltammetry results, reduction in ZnO, LiZn, and Li2Zn3 formation was dominant during formation cycle of MicNo ZnO along with excellent reversibility. After lithiation, phase change from crystalline ZnO into metallic Zn and amorphous ZnO was observed from transmission electron microscopy analysis. Improved Li+ diffusion in SEI and pore channels, better charge-transfer characteristics, poor electronic contact, and high EDL capacitance are other features of MicNo ZnO according to electrochemical impedance spectroscopy., Anadolu University Scientific Research Projects UnitAnadolu University [1802F030], Anadolu University Scientific Research Projects Unit, Grant/Award Number: 1802F030

WOS: 000382269800031, Understanding growth mechanisms usually leads to the successful preparation of a targeted microstructure. However, the large number of parameters that influence the shape and the size of nanostructures often make it difficult to predict the outcome. We investigated the growth of wurtzite-type ZnO by closely following such a multistage process. We associated the diverse morphology of the precipitated crystals, prepared under the same hydrothermal conditions, to the differences in the transient crystallization processes during the precipitation. By altering the pH of the suspension after the precipitation, we gain control over the resulting morphology of the ZnO and show how to grow identical crystallites with different shapes and crystal sizes. Here we report, for the first time, on how ZnO platelets grow in a certain Zn2+/OH- ratio along the basal and one of the prismatic directions to form sphalerites with very high surface area. We also offer an explanation as to how sphere-like hierarchical structures composed of plate- or rod-like ZnO crystals form through self-assembly driven processes, Slovenian Research Agency [P2-0084, L2-4192]; Turkish Academy of Science (via GEBIP-Outstanding Young Investigator Award Program); Erasmus Program (Lifelong Learning Programme IPS) [2008/09-1], The financial support of the Slovenian Research Agency (Program Contract No. P2-0084 and Project No. L2-4192), the Turkish Academy of Science (via GEBIP-Outstanding Young Investigator Award Program for Prof. Ender Suvaci) and the Erasmus Program (Lifelong Learning Programme IPS Jozef Stefan No. 2008/09-1) are gratefully acknowledged.

Zn2SnO4 (ZTO) is an important electroceramic material having unique optical and electrical properties. For some applications, ZTO has to be used in an aqueous media under various conditions; however, there is still limited understanding about the relationship between particle characteristics and chemical stability in aqueous media. Therefore, in this study, chemical stability of solid state (S-ZTO) and hydrothermally synthesized (H-ZTO) powders was investigated under different conditions; pH, time and particle characteristics as well as dye-sensitized solar cell conditions. Analyses revealed that the acidic media resulted with higher dissolution rate of Zn2+ and Sn4+ ions compared with the basic media. H-ZTO is more stable with respect to S-ZTO particles due to less defect concentration. Zn2+ ions dissolve via proton promoted dissolution mechanism in acidic media. Moreover, cationic field strength of the ions in ZTO results in differential dissolution of Sn4+ and Zn2+ ions, which were determined as maximum 0.04% and 0.4%, respectively. TEM studies revealed that no interaction layer found at the surface of particles, thus ZTO powders are chemically stable. Physical and electrical properties of aged ZTO powders prove that ZTO material can be used in different applications which involve acidic or basic aqueous media.

WOS: 000445162500036, The research objective of the present study was to evaluate antimicrobial activity of ZnO powder systems in different size, shape and array platelet forms with undoped and doped Ag at different concentrations. In particular, a novel particle morphology, called MicNo-ZnO, is micron size hexagonal platelet particles composed of primary nano ZnO particles, and its' doped forms with Ag was tested as an antimicrobial agent as first time in the literature. Eleven test microorganisms were used to investigate antimicrobial performance of particles including Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Candida albicans, Candida glabrata, Candida zeylanoides, Aspergillus flavus, Aspergillus fumigatus, Fusarium solani and Penicillium citrinum. The results show that investigated nanoparticles have broad-spectrum antimicrobial activity. In addition, effectiveness of nanoparticles increases by doping of Ag and especially MicNo particles doped with 0.05 mol % of Ag concentration demonstrated the highest antimicrobial activity among tested particles. These results are considered, MicNo-ZnO display a great potential for different industrial applications., Anadolu University, Scientific Research Project [1101F020], This research financially supported by Anadolu University, Scientific Research Project, Project Number is: 1101F020.

WOS: 000419096700013, In recent years, potassium sodium niobate (K0.5Na0.5NbO3, KNN) has become popular and promising among perovskite lead-free piezoceramic systems. In this study, the chemical stability of KNN powders in aqueous medium was investigated as a function of pH, time, and powder surface area. To better understand the dissolution behavior of the complex KNN stoichiometry, subconstituents such as potassium niobate (KNbO3, KN) and sodium niobate (NaNbO3, NN) were investigated separately first. Results showed that all of the cations in the structure underwent dissolution in different values. Indicating that KNN undergoes incongruent dissolution in aqueous medium, the dissolution of A site cations was higher at lower pH while the dissolution of B site cations increased at higher initial pH. The order of released cation concentrations (C-A1=K>C-A2= Na>C-B=Nb) fits with inverse relationship of cation field strength (FS) order, B=Nb-FS(5+)>A(2)=Na-FS(+)>A(1)=K-FS(+), at pH 4, 7 and 10 for NN, KN, and KNN. Calculated diffuse layer thickness from the ICP data confirmed to outer amorphous layer in TEM image. Also, the ratio of normalized cation concentration versus surface area of powders showed that incongruent dissolution kinetic was driven by the diffusion step., Turkiye Bilimler Akademisi [TUBA-GEBIP], Turkiye Bilimler Akademisi, Grant/Award Number: TUBA-GEBIP

WOS: 000452762000010, Amorphous films of two varieties of zinc stannate (ZnSnO3 and Zn2SnO4) have been considered that were fabricated by radio-frequency sputtering of ceramic compound targets containing ZnO and SnO2 in 1: 1 and 2: 1 ratios. The elemental and phase compositions of the films and their optical and electrical parameters were determined. The transparency of the films in the visible spectral range is on average 87%. Zinc stannate amorphous films have a high electrical conductivity in contrast to amorphous ZnO and SnO2. This phenomenon, which makes it possible to use zinc stannate amorphous films in transparent and flexible electronics, is explained., Russian Foundation for Basic Research and TUBITAK [12-02-91373_CT_a], This study was supported in part by the Russian Foundation for Basic Research and TUBITAK, grant no. 12-02-91373_CT_a.

WOS: 000360511400014, The preparation of (SnO2)(x)(ZnO)(1-x) powder as a ceramic target material via hydrothermal synthesis within a broad range of x values (x = 0-1) was investigated. The phase development and particle characteristics of the Zn2SnO4 powders were evaluated. The phase formations of the (SnO2)(x)(ZnO)(1-x) system in the range from x = 0.0 to 1.00 were mapped, and the ZnO, SnO2 and Zn2SnO4 phases were found to depend on the changing x value. The effects of the processing parameters, including the treatment temperature (180-220 degrees C), time (0-24h) and initial concentrations of precursors (Sn:Zn = 0.125:0.3,0.2:0.48, 0.25:0.6, 0.35:0.84, 0.5:1.20), on the formation mechanism of Zn2SnO4 were discussed in detail. Almost single phase Zn2SnO4 occurs only when x = 0.29 (Zn/Sn= 2.4:1) for the (SnO2)(x)(ZnO)(1-x) composite system at 220 degrees C for 24h. The results reveal that the target prepared from synthesized Zn2SnO4 powder can be successfully used to develop thin film transistor channels, Scientific and Technological Research Council of Turkey (TUBITAK) [111M670]; Anadolu University [1303F056, 1305F086]; State Program of Ministry Science and Education of Russian Federation [280, 3.574.2014/K], This study was sponsored by a bilateral research project between Turkey & Russia under the contact number 111M670 by the Scientific and Technological Research Council of Turkey (TUBITAK). The work was also supported by Anadolu University under the contract numbers 1303F056 and 1305F086. The work was also supported by the State Program of Ministry Science and Education of Russian Federation project N 280 and program N 3.574.2014/K. We would like to thank to Pinar KAYA and Tayfun OZMEN for their helps.

WOS: 000426409400025, PubMed ID: 29223573, Recently, designed platelet shaped micron particles that are composed of nano primary particles, called MicNo (= Micron + naNo) particles, have been developed to exploit the benefits of nano size, while removing the adverse effects of nanoparticles. It has been shown that MicNo-ZnO particles exhibit both micron and nanosized particle characteristics. Although physical and chemical properties of MicNo-ZnO particles have been studied, their biocompatibility has not yet been evaluated. Accordingly, the research objective of this study was to evaluate in vitro cytotoxicity, genotoxicity and phototoxicity behaviors of designed MicNo-ZnO particles over human epidermal keratinocyte (HaCaT) cells. MicNo-ZnO particles exhibit much less cytotoxicity with IC50 concentrations between 40 and 50 mu g/ml, genotoxicity above 40 mu g/ml and lower photo genotoxicity under UVA on HaCaT than the ZnO nanoparticles. Although their chemistries are the same, the source of this difference in toxicity values may be attributed to size differences between the particles that are probably due to their ability to penetrate into the cells. In the present study, the expansive and detailed in vitro toxicity tests show that the biocompatibility of MicNo-ZnO particles is much better than that of the ZnO nanoparticles. Consequently, MicNo-ZnO particles can be considered an important active ingredient alternative for sunscreen applications due to their safer characteristics with respect to ZnO nanoparticles., Scientific and Technological Research Council of Turkey [109M585]; Anadolu University Scientific Research Projects Commission [1101F020], This research was supported financially by the Scientific and Technological Research Council of Turkey (Project number: 109M585) and the Anadolu University Scientific Research Projects Commission (Project number: 1101F020). The authors would like to thank Ismail Sahin for his assistance for the UV visible analyses of the nano ZnO and MicNo (R)-ZnO particles.

WOS: 000399855700011, The research objective of the study was to increase the current understanding about how oxide compositions (CaO, MgO and SiO2 ratios) influence the (1) crystallization behaviour of starting frits, and subsequently (2) morphological features of diopside crystals, formed after wall tile industrial firing. It has been shown that the replacement of CaO and MgO at the expense of SiO2 causes a decrease in the crystallization temperature. The increase of CaO content also results in lower softening temperature and faster densification. SEM results of the glazes showed that spherical and needle-shape diopside crystals were formed during heating. While increase of MgO content results in finer needle-shape crystals, increase of CaO results in coarser spherical-shape crystals. Although all the glaze formulations showed a high whiteness index, lower densification and higher crystallization in the glazes caused an unfired matt appearance., Turkish State Planning Organization through the Industrial Doctorate Programme; Yurtbay Seramik Company, The financial support from Turkish State Planning Organization through the Industrial Doctorate Programme for this project and Yurtbay Seramik Company are also gratefully acknowledged.

WOS: 000461138500012, Three different graphite-based powders (expandable graphite and two different nano-graphite powders) were investigated as starting materials for an effective liquid phase exfoliation process in isopropyl alcohol (IPA). The prepared dispersions were analyzed and compared in terms of their graphene concentration, stability, number of graphene layers and quality, as well as the electrical conductivity of the prepared graphene-based materials. Good quality graphene dispersions (I-D/I-G < 0.3) with a relatively high concentration (similar to 1.1 mg/ml) were prepared in IPA within 90 min sonication time by utilizing a high specific surface area (similar to 175 m(2)/g) nano-graphite powder derived from natural graphite. Transmission electron microscope analyses of this sample revealed mostly folded and scrolled few layer graphene (FLG) sheets (, Anadolu University Scientific Research Projects Commission [1110F155, 1101F005], The financial support for this study by Anadolu University Scientific Research Projects Commission (under the project numbers of 1110F155 and 1101F005) is gratefully acknowledged. The authors also thank to Dr. Pascal Puech (CEMES, Toulouse) for discussions on Raman analyses and to Lucien Datas for TEM analyses which were performed at R. Castaing characterization platform, UMS 3623.

WOS: 000374082900028, Graphene platelets (GPLs) containing Al2O3 nanocomposites, which exhibit anisotropic microstructure, have been prepared by spark plasma sintering (SPS), and effects of this anisotropy on mechanical, electrical and thermal properties of the nanocomposites have been investigated. 3 vol.% GPLs addition into monolithic Al2O3 caused fracture toughness (K-IC) to increase by 26.7% in the in-plane direction and to decrease by 17.2% in the through thickness direction. K-IC started to decrease in the in-plane direction and to increase in the through-thickness direction with further increase in the GPLs amount. The electrical conductivity of the nanocomposites exhibited a slight anisotropy with a lower resistivity in the in-plane direction. Oriented GPLs also led to a less resistive heat conduction path in the in-plane direction. similar to 44% increase in the in-plane thermal conductivity was achieved at 600 degrees C with 15 vol.% GPLs addition into the monolithic Al2O3 and this resulted in similar to 52% increase in the k(in-plane)/k(through-thickness) ratio, Anadolu University Scientific Research Projects Commission [1110F155, 1101F005], The financial support for this study by Anadolu University Scientific Research Projects Commission (under the project numbers of 1110F155 and 1101F005) is gratefully acknowledged.

WOS: 000385900100060, Low-pressure chemical vapor deposition synthesis of graphene films on two different Cu foils, with different surface oxygen and carbon contents, was performed by controlling H-2 and/or Ar flow rates during heating. The influences of heating atmosphere on the final impurity level, quality of the synthesized graphene films and thickness uniformity were investigated depending on Cu foil impurities. Heating of carbon-rich, but oxygen-poor Cu foil in H-2 environment resulted in covering the foil surface by residual carbon which then acted as active sites for multilayer graphene growth. Ar-only flow was required during heating to promote high quality graphene growth on this foil. On carbon-poor, but oxygen-rich Cu foil high quality graphene growth was promoted when the heating was carried out under Ar/H-2 environment. Almost no carbon residues were observed on this foil even under H-2 only flow during heating. The heating atmosphere affected not only graphene growth, but also the type and amount of impurities formed on the surface. H-2 and Ar/H-2 heating resulted in the formation of spherical nanometer-sized impurities, while irregular-shaped, large (a few mu m) SiO2 impurities were observed when Ar alone was used during heating. Quality of the grown films was tested by Quantum Hall Effect measurements, Anadolu University Scientific Research Projects Commission [1110F155, 1101F005], The financial support for this study by Anadolu University Scientific Research Projects Commission (under the project numbers of 1110F155 and 1101F005) is gratefully acknowledged. The authors also thank Jerome Esvan (CIRIMAT, Toulouse) for XPS analyses and Lucien Datas for TEM analyses which were performed at R. Castaing characterization platform, UMS 3623.

WOS: 000374774100012, Effects of different types and shapes of titanium dioxide, zinc oxide, and magnetite nanofillers on the rheological behavior of polyol/nanofiller suspensions, on the rigid polyurethane foam formation reaction, and hence on the final microstructure were investigated. The rheological percolation threshold of polyol/nanofiller suspensions decreased as the aspect ratio of nonspherical nanoparticles (platelet or rod) increased, regardless of the nanofiller type. The results of reaction kinetics showed that above a critical surface area (approximate to 30 m(2)), independently of nanofiller type, the reaction rate increased as the surface area increased. The introduction of oxide surfaces reduced the final cell size until a critical surface area (approximate to 30 m(2)). However, above this critical value cell size distribution gets wider and the cell size can no longer be correlated with the surface area. In the latter case, an increase of the reaction rate and the polymerization reaction being exothermic may facilitate uncontrolled cell nucleation, growth, and hence coalescence which results in an uncontrolled foam structure, Scientific and Technological Research Council of Turkey (TUBITAK); Scientific Projects Commission of Anadolu University [1404F169], Burcu Ceren Dabak is acknowledged for the production of TiO2 nanorods and ZnO nanoplatelets used in this study. The Scientific and Technological Research Council of Turkey (TUBITAK) and the Scientific Projects Commission of Anadolu University (under the contract number of 1404F169) are also gratefully acknowledged for their financial support.

Semiconducting metal oxide sensors have been widely studied due to their small dimensions, low cost and low power consumption. Among semiconductor oxide materials, zinc oxide (ZnO) is a very interesting one due to its chemical and thermal stability, its large exciting binding energy and band gap as n-type semiconductor, and, especially, to its high response to toxic and combustible gases. ZnO is a potential material for gas sensor applications because of its high piezoelectric coefficient, great stability of its hexagonal phase and its pyroelectric property. Hydrothermal synthesis is one of the most useful methods to produce homogeneous, nanosized ZnO powders with high purity, controlled particle size and morphology. Therefore, ZnO with various morphologies can be synthesized via simple hydrothermal reactions. The research objectives of this study were to understand formation and growth process of ZnO particles with various morphologies and to investigate role of starting materials, (i.e., zinc chloride (ZnCl2) and zinc nitrate hexahydrate (Zn(NO3)2.6H2O) on the particle morphology. In the present study, ZnO particles with various morphologies were synthesized via an unstirred hydrothermal method. When the using ZnCl2 as a precursor, the final morphology was rod like with a taped tip (length of the rod 0.5-1um ) after 12 h at 100°C. On the other hand, final morphology of the produced ZnO particles was branch rodlike (5-10um) when using Zn(NO3)2.6H2O as precursor under the same synthesis conditions. Accordingly, a proposed growth mechanism has been suggested. Keywords: ZnO; Hydrothermal synthesis; Phase development; Morphology; Growth mechanism DOI: 10.17350/HJSE19030000034 Full Text

WOS: 000284569900018, Suspensions consisting of precursor alpha/beta SiAlON forming powders azeotropic solvent mixture of 60 MEK/40E dispersant binder, and plasticizer were optimized for tape casting by theological measurements and tape properties Sodium tripolyphosphate (STPP) was introduced as a dispersant for low temperature applications of alpha/beta SiAlONs Optimum STPP amount was determined as 0 012 g/m(2) (of the particle surface) for stable alpha/beta SiAlON suspensions Different amounts of binder/plasticizer mixtures were added to the slurries and the effects on theological and green tape properties were investigated Green tapes with dibutyl phthalate (DBP), and plasticizer mixture, poly(ethylene glycol) (PEG) and DBP, exhibited centered cracks with high plasticity, on the other hand, polyvinyl butral (PVB) and PEG showed no crack but low plasticity Therefore, many different parameters were found to be effective on final tape properties In addition, tapes were prepared with 6 vol% PVB + PEG, sintered at 1800 degrees C for 2 h and exhibited almost 97%TD in room temperature applications of alpha/beta SiAlONs (C) 2010 Elsevier Ltd All rights reserved

Nano boyutlu SnO2elektroseramik tozların hidrotermal yöntemle üretimi, tozların oluşum mekanizmasını anlamak üzere başlangıç derişimi ve işlem süresinin bir fonksiyonu olarak incelendi. SnO tozları hidrotermal yöntemle su içeren kalay oksitten 2000C de başarıyla sentezlendi. 170 m2/g a kadar spesifik yüzey alanınasahip kristal SnO2 tozları kalsinasyon gerektirmeden tek basamakta üretildi. Başlangıç metal katyon derişimi 0.0125 den 0.05 M a çıkarıldığında Ostwald irileşmesi türünde bir büyüme süreciyle kristalit boyutunun 3.1 den 4.6 nm ye çıktığı gözlendi. Kalay oksit partiküllerinin oluşumu 1 ile 24 saat aralığında değiştirilerek incelendi ve sentez süresinin bir fonksiyonu olarak difüzyon kontrollü büyüme davranışı tespit edildi

In present work we demonstrate the synthesis of textured 60BiFeO3–40PbTiO3 (60:40 BFPT) by using the templated grain growth technique with platelets of BaTiO3. Synthesised 60:40 BFPT has been examined by High-energy x-ray diffraction utilizing a synchrotron x-ray source. The crystallographic structure refinement results revealed the co-existence of monoclinic and tetragonal phases. By employing an external electric field, the mixed monoclinic/tetragonal phases transformed to the predominantly tetragonal phase. In addition, a crystallographic texture refinement was completed on unpoled state of 60:40 BFPT which showed the sample had 1.3 multiples of random distribution (MRD) {100} crystallographic textured in tetragonal phase. However, magnetic measurements showed isotropic ferromagnetism for the sample which is not in agreement with the crystallographic texture properties of the sample. Low temperature magnetic transition has been found in zero field cooled—field cooled (ZFC-FC) measurements. This could be due to the possible existence of a secondary magnetic phase, which dominated the magnetic result.

WOS: 000279277500006, The relationship between microstructure texturing and electrical characteristics of a ZnO-based varistor system was investigated in comparison with a varistor system having the same chemical composition but conventional microstructure. Highly textured ZnO-based varistors were produced via the templated grain growth (TGG) technique. Stereological analysis, electron back-scattered diffractometry (EBSD) and X-ray diffractometry (XRD) were conducted to analyze texture development and orientation distribution. The degree of orientation, r, calculated from the (0 0 0 1) EBSD pole figure, was 0.34; the texture fraction, f (Lotgering factor), calculated from the XRD data, was 0.98 for the samples produced via TGG. The threshold voltages were found to be anisotropic, consistent with the observed morphological texture. The non-linear coefficients, a, did not exhibit a significant difference as a function of direction, even in the highly textured samples. However, different types of grain boundary characteristics depending on the direction were identified with 0.42, 0.69 and 1.14 eV Schottky barrier heights., Anadolu University [060243]; Scientific and Technological Research Council of Turkey [105M124]; Slovenian Research Agency [P2-0084-0106/05, Bi-TR/05-08-003]; Turkish Academy of Sciences, The authors would like to thank Prof. Dr. Muharrem Timucin, Prof. Dr. Yuksel Ergun, Dr. Ibrahim Cam and Dr. Aleksander Recnik for fruitful discussions throughout this study. In addition, they would like to thank Mr. Hasan Yungevi, Ms. Matejka Podlogar and Ms. Sasa Nastran for their help during experimental work. The financial support from Anadolu University Scientific Research Projects Commission (under the contract number: 060243), the Scientific and Technological Research Council of Turkey (under the contract number: 105M124) and the Slovenian Research Agency (Program Contract No. P2-0084-0106/05 and project grant Bi-TR/05-08-003) for this study are also gratefully acknowledged. In addition, the authors acknowledge the Turkish Academy of Sciences for the financial support for Dr. Ender SUVACI through GE-BIP-Outstanding Young Investigator Award Programme.

5th International Symposium on Nitrides -- APR 03-05, 2006 -- Anadolu Univ, Eskisehir, TURKEY, WOS: 000248530400012, In this study, textured alpha-SiAlON ceramic was produced by templated grain growth process. In order to enhance the alignment of the seeds, gated tape casting arrangement was utilized. Y-Ce codoped seeds were synthesized to induce the preferred orientation. For the production of the seeds, Ce3+ was used as a sintering additive due to its well-known effect on the formation of elongated a-SiAlON grains. In addition, Y3+ was used to stabilize Ce3+ in a-SiAlON structure. Gated tape casting arrangement was also used to enhance the alignment of the seeds in the green tape. After the lamination and sintering, preferentially aligned a-SiAlON grains were observed by the microstructural investigation. In addition, XRD results obtained from the planes parallel and perpendicular to the casting direction indicated the alignment of grains in a-SiAlON ceramics. Hardness measurements also confirmed that the alignment of the grains results in 8% increase in hardness value of the plane perpendicular to the casting direction with respect to that of the parallel one., Turkish Ceram Soc, Sci & Technol Res Council Turkey

WOS: 000364257600011, The templated grain growth technique was used to synthesise textured 60BiFeO(3)-40PbTiO(3) (60:40BFPT). Both Aurivillius (Bi4Ti3O12, PbBi4Ti4O15) and perovskite templates (BaTiO3, SrTiO3) were used to prepare 60:40BFPT. Only BaTiO3 templates were found to successful impart a texture to the ceramic matrix. In the case of perovskite templates, ferroelectricity was evident from saturated polarisation hysteresis loops. Saturated polarisation loops were achieved due to the substitution of Ba2+ or Sr2+, which reduces the coercive field. SrTiO3 and BaTiO3 templated ceramics showed remanent polarisation of 30 and 36 mu C/cm(2), respectively. Aurivillius templates did not generate ferroelectric materials. Because of their high chemical stability in this system, BaTiO3 templates appear to be the best candidate for fabricating textured BFPT by the reactive templated grain growth method

Electrophoretic deposition technique is a versatile coating method. With this method not only flat surfaces but also curved or rough surfaces can be coated in various thicknesses. In this study, BaTiO3 nanocrystals were synthesized with a novel nonaqueous method. In a simple one pot reaction process, the metallic barium is directly dissolved in benzyl alcohol at slightly elevated temperatures. After the addition of titanium isopropoxide and subsequent solvothermal treatment nearly spherical BaTiO3 nanocrystals typically 5 nm in diameter were obtained. The stability of the suspension in ethanol and nanocrystalline particle size distribution was measured by Malvern Nano-ZS. The BaTiO3 suspensions were directly used in an electrophoretic deposition process without any additional operation. Pt plated alumina was used as substrate. Various voltages were applied by altering the cathode to anode distance as well as deposition time for optimal process control. Because of the ethanol adsorbed on the surface of the nanoparticles, application of high voltages was possible without causing hydrolysis. The deposited surface coatings were dried in air atmosphere and sintered at different temperatures. SEM, EDX and XRD analysis were employed for the investigation of the coating.

9th International Ceramic Processing Science Symposium -- JAN 08-11, 2006 -- Coral Springs, FL, WOS: 000237812100030, The effect of oriented alpha-Al2O3 platelets on densification and shrinkage behavior of tape-cast alpha-Al2O3 during solid-state sintering was studied using dilatometric sintering shrinkage experiments and microstructural characterization. Platelet-free alumina samples exhibit isotropic shrinkage with an similar to 17% linear final shrinkage. The addition of platelets retards densification, and results in anisotropic shrinkage. Initially during sintering, shrinkage is isotropic for platelet-containing systems; however, it becomes highly anisotropic by inhibition of shrinkage in the platelet orientation direction. In the 10 vol% platelet-containing system, shrinkage was similar to 12% in the casting and the transverse directions and similar to 20% in the direction perpendicular to the casting plane.

The application of material chemistry concepts to processing powder suspensions including solution thermodynamics will be demonstrated on several material systems, notably the complex metal oxide, barium titanate, in aqueous environments. After a discussion of the relevant thermodynamic and kinetic issues for fine particles in liquids, various characterization approaches to understand and control the behavior of powders in liquids will be discussed. Various colloidal characterization techniques, high-resolution TEM, and chemical analyses of both the solution and solid exposed to solution have been used to study the nature of the chemical reactions and subsequent altered surface layers in the barium titanate–water system. The key factor in developing an effective aqueous processing scheme for any water sensitive material (and all metal oxides are water sensitive) in aqueous suspension, is recognition that deleterious surface hydrolysis reactions must be prevented. It is shown that local chemical inhomogeneities play a role in abnormal grain growth in the barium titanate system exposed to aqueous environments, but can be controlled with appropriate chemical passivation approaches. The success of a passivation–dispersion approach in the aqueous processing of these materials will be discussed as well as the implementation of the general concept of material chemistry approaches to the aqueous processing of other water sensitive materials.

WOS: 000230039800024, Textured, dense zinc oxide varistors were successfully fabricated by Templated Grain Growth (TGG) technique. Rod-like, anisotropic ZnO particles (templates) were synthesized by homogeneous precipitation method. The templates are aligned in such a position where c-axes of the templates are parallel to the tape casting direction during the modified tape casting process. Since zinc oxide varistors are liquid phase sintered, addition of the templates to initial powder mixture does not result in constrained densification. The aligned zinc oxide templates grow anisotropically during sintering. (11 (2) over bar0) and (10 (1) over bar0) prismatic planes of the ZnO crystals (templates) grow faster than the other ZnO crystal planes. The growth of the templates results in texture development in zinc oxide varistors. As sintering temperature increases, fraction of textured grains in the microstructure increases. A template growth mechanism is also proposed for texturing zinc oxide varistors by TGG

The effect of attrition milling on the solid-state oxidation of aluminum powder is important for the reaction-bonded aluminum oxide process. Attrition milling increased the surface area to 14.4 and 20.2 m2/g versus 1.2 m2/g for unmilled powder and smeared the Al particles, and the surface was hydrolyzed to form bayerite and boehmite. Upon heating the hydroxides decompose to form an 11–13 nm thick amorphous plus γ-Al2O3 layer which subsequently retards oxidation kinetics. The oxidation per unit area decreases for the higher surface area powders at temperatures below the critical temperature but the total oxidation of the milled powder is ∼70% versus ∼9% for the as-received powder because of the higher surface area. The critical temperature depends on Al particle surface characteristics and is defined as the transition temperature above which the initial rate of oxidation is linear, not parabolic. Above the critical temperature the oxidation per unit area decreases significantly. In addition, linear oxidation occurs faster than parabolic oxidation and thus the initial fast oxidation kinetics (i.e., linear) can cause thermal runaway during oxidation. Therefore, oxidation below the critical temperature is essential to maximize solid-state oxidation and to prevent thermal runaway. The critical temperatures for the as-received (1.24 m2/g), the 6 h (14.4 m2/g), and 8 h (20.2 m2/g) attrition-milled Al powders were 500°, 475°, and 500°C, respectively. A model for oxidation during the parabolic and linear oxidation stages is presented.

Crystallographic texturing of polycrystalline ferroelectric ceramics offers a means of achieving significant enhancements in the piezoelectric response. Templated grain growth (TGG) enables the fabrication of textured ceramics with single crystal-like properties, as well as single crystals. In TGG, nucleation and growth of the desired crystal on aligned single crystal template particles results in an increased fraction of oriented material with heating. To facilitate alignment during forming, template particles must be anisometric in shape. To serve as the preferred sites for epitaxy and subsequent oriented growth of the matrix, the template particles need to be single crystal and chemically stable up to the growth temperature. Besides templating the growth process, the template particles may also serve as seed sites for phase formation of a reactive matrix. This process, referred to as Reactive TGG (RTGG), has been used to obtain highly oriented Pb(Mg1/3Nb2/3)O3-PbTiO3, Sr0.53Ba0.47Nb2O6, and (N...

Autumn Meeting of the Japan-Institute-of-Metals -- SEP 22, 2001 -- KYUSHU, JAPAN, WOS: 000180681300058, Fracture behaviors were investigated in the laminated alumina composite ceramics. To improve the mechanical properties of alumina ceramics, templated grain growth (TGG) technique of alpha-Al2O3 platelet and LaPO4 as a second phase were introduced. Textured samples were made by the lamination of green tapes through the tape-casting method, while random samples were made through the conventional powder processing method. Green compacts were sintered at 1600degreesC for 2 h in air. Fracture toughness was tested using indentation strength bending (ISB) method. Indentation on the sample surface was produced by Vickers indent at various loads. From the bending test, enhanced fracture toughness was found in the textured composite, compared to the random composite., Japan Inst Met

IEEE Joint Int Symp on the Applications of Ferroelectrics / Int Workshop on Acoustic Transduction Materials and Devices / Workshop on Piezoresponse Force Microscopy -- MAY 12-16, 2014 -- PA, WOS: 000363973100043, The template grain growth technique was used to synthesis textured 60BiFeO(3)-PbTiO3 (60:40BFPT) by using platelets of BaTiO3 as template. Synchrotron measurement clearly showed textured 60:40BFPT. Moreover, in situ high energy synchrotron radiation was employed to investigate the influence of an external electric filed on crystallographic structure of mixed phase 60:40BFPT. Application of an electric field >= 1 kV/mm resulted in phase transformation from mixed rhombohedral/tetragonal phases (approximate to 73.5% tetragonal / 26.5% rhombohedral) to predominately tetragonal phase (approximate to 95%) at applied field of 6 kV/mm. A crystallographic texture refinement was done by using software package materials analysis using diffraction (MAUD) with a 4th order spherical harmonic orientation distribution function (ODF). This refinement was completed using a P4mm+Cm structure model. Texture coefficients were constrained such that the equivalent texture coefficients of each phase are the same. The resulting texture refinement determined that sample has a 1.3 multiples of random distribution (MRD) {100} crystallographic texture., IEEE

WOS: 000340381700023, The study is concerned with high-purity SnO2 and ZnO powders produced from salt solutions of corresponding metals by low-temperature hydrothermal synthesis. Fragments of SnO2 and ZnO ceramic targets formed as 1 x 8 cm bars are fabricated by dry pressing. The bars are used to form composite targets for ion-beam sputtering and the fabrication of compositionally different (SnO2) (x) (ZnO)(1 - x) (x = 1-0.5) films appropriate for the production of gas sensors or transparent electronic devices. The optical and electrical parameters of the films with different compositions are studied., Russian Foundation for Basic Research [12-02-91373_ST_a], This study was supported by the Russian Foundation for Basic Research, joint Russian-Turkish project RFBR-TUBITAK, no. 12-02-91373_ST_a.

WOS: 000341097000015, The gel electrolyte is an important component of the valve-regulated lead-acid (VRLA) batteries. In this study, fumed silica-based gel electrolyte systems were prepared. In this concept, several important parameters controlling the performance of the GEL-VRLA battery, such as the sulfuric acid and fumed silica concentrations, gel formulation, gelling time and rate, and different additives (Na2SO4 and MgSO4), were scientifically investigated. The gel formulations were characterized by cyclic voltammetric and electrochemical impedance spectroscopic methods. The optimum parameters were determined by using the results of anodic peak currents and redox capacities, R (s) and R (ct) values. Addition of 6 % (w/w) fumed silica to 30 % (w/w) sulfuric acid, for preparation of gelled electrolyte, increased the battery performance significantly. According to the results of the transmission electron and optic microscope images of the gel electrolytes, the three-dimensional gel structure was prepared successfully. The optimization of sulfuric acid concentration and amount of Na2SO4 and MgSO4 additives were examined for the first time in detail by cyclic voltammetry, electrochemical impedimetry, and battery test. Na2SO4 and MgSO4 additives make a good combination with a gelled-electrolyte system and improve the charge/discharge capacity according to sulfuric acid electrolytes. According to the experimental results, the fumed silica-based gel electrolyte system has a great potential for application in gelled electrolyte VRLA batteries., SAN-TEZ program of Ministry of Science, Industry and Technology, Republic of Turkey [00897.STZ.2011-1]; Anadolu University; Ericsson Turkey, This work was supported by the SAN-TEZ program (No. 00897.STZ.2011-1) of Ministry of Science, Industry and Technology, Republic of Turkey, with Anadolu University, and Ericsson Turkey. Y. Sahin thanks to Oktay Uysal for his support to this study. The authors would like to thank AUBIBAM for the TEM analysis.

7th Conference of the European-Ceramic-Society -- SEP 09-13, 2001 -- BRUGGE, BELGIUM, WOS: 000172651400102, Highly textured, dense alumina ceramics were fabricated by a processing route which utilizes a mixture of Al metal powder, alumina powder, alumina platelet (template) particles and a liquid phase former. The process involves dry forming the powder mixture (e.g., uniaxial pressing) to align the plate-like template particles. Texture quality can be controlled by compaction strain. Thermodynamic conditions favorable for template growth occur when the size ratio between the template thickness and matrix grains is 1.5., European Ceram Soc, Belgian Ceram Soc

Kinetics of texture development in liquid-phase sintered alumina ceramics has been studied during templated grain growth (TGG); a technique for developing crystallographic texture in ceramic bodies via the grain growth of aligned anisometric particles in a dense and fine grain size matrix. It has been shown that significant template growth is observed only at high densities (∼91% TD). The template growth in the radial direction followed a cubic growth law just like the growth of a single crystal {1120} and {0112} planes during the initial stage of TGG, suggesting that diffusion is the rate-limiting step for radial growth.

The objective of this review is to highlight the theoretical and practical aspects of particle morphological control. Materials with directional properties are opening new horizons in material science. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, and certain metal and ceramic alloys. The new applications and the need for model particles in scientific investigations are rapidly outdistancing the ability to synthesize anisotropic particles with specific chemistries and narrowly distributed physical characteristics (e.g. size distribution, shape, and aspect ratio). Anisotropic particles of many compositions have been produced but only a few (γ-Fe2O3 and AgI) are produced with any degree of chemical and physical control. These two examples are the result of literally decades of study. Unfortunately, the science and technology (mainly the technology) that have evolved are maintained as proprietary information. Thus, while we generally know what systems yield single crystal, anisotropic-shaped particles, we do not know how to make powders of these crystals with the desired control of shape uniformity, aspect ratio and phase composition. Particle shape control is a complex process requiring a fundamental understanding of the interactions between solid state chemistry, interfacial reactions and kinetics, and solution (or vapor) chemistry. During synthesis of other than a large single crystal the parameters controlling crystal growth must be balanced with the requirements for anisotropic powder nucleation and growth. Although there has been considerable progress in large single crystal growth and the synthesis of powders composed of monodispersed, spherical particles, these efforts have not often been transferred to the synthesis of anisotropic particles.

Single crystals of α-alumina with {0001}, {11 $$\overline 2 $$ and {01 $$\overline 1 $$ 2} orientations were embedded in a matrix of liquid phase sintered alumina to study α-alumina single crystal growth in the presence of a calcium aluminosilicate liquid. Growth on the {11 $$\overline 2 $$ 0} and {01 $$\overline 1 $$ 2} surfaces was observed to occur by a diffusion-controlled mechanism while growth on the basal surface was controlled by two-dimensional nucleation. Growth models, which incorporate the change in matrix grain size, were derived and shown to fit the growth kinetics.

Highly textured, dense alumina ceramics were fabricated by a new processing route which utilizes a mixture of Al metal powder, alumina powder, alumina platelet (template) particles and a liquid phase former. The process involves dry forming the powder mixture (e.g. uniaxial pressing, and roll compaction) to align the plate-like template particles. The addition of a calcium aluminosilicate glass reduces constrained densification by the template particles and allows attainment of high density at ∼1450°C. The degree of orientation (i.e. r is 1 for a random sample and 0 for a perfectly textured material) and volume fraction of textured material, f, were measured by X-ray-based rocking curve technique and SEM-based stereological analysis, respectively. It has been shown that texture quality (the r parameter) is controlled by initial strain during forming, sintering time and temperature. In addition, alumina ceramics with the volume fraction of textured material ranging from 1 to ∼100% can be obtained.

The reaction bonding of aluminum oxide (RBAO) process was analyzed from the milling of the precursor mixtures to the sintering of the reaction bonded α-alumina as a function of precursor powder composition, Al particle size, temperature, and heating rate. The RBAO process involves both solid-gas (T TM,AI) oxidation of Al + α-Al2O3 powder compacts. It has been demonstrated that maximum Al content of the precursor powder is limited to 60 vol %. In addition, it was observed that the initial Al particle size affects the oxidation behavior significantly and hence final properties of α-Al2O3 compacts. Therefore, the initial Al particle size is very critical for the RBAO process. The critical Al particle size (i.e., the largest Al particle size can be used to obtain dense ceramic materials by the RBAO process) was determined as ∼1.5 μm. It has been demonstrated that heating rate can be used to improve the final microstructures of RBAO ceramics. Although there is no large (>4 vol %) amount of ZrO2 addition, alpha aluminum oxide ceramics with 97% TD have been produced by optimizing the processing parameters such as fine (

WOS: 000313379400129, The stability of pigment particles can be affected by physico-chemical interactions between the pigment particles and a solvent. In this study, the surface charges and stabilities of blue V-ZrSiO4 pigments in aqueous (water) and non-aqueous (diethylene glycol) suspensions were investigated. As a function of pH, the isoelectric points (IEP) for the commercial and synthesised pigments were determined to be 2.2 and 1.7, respectively. ICP-OES results show that the cations of V-ZrSiO4 pigments dissolve in both aqueous and non-aqueous systems. The dissolution of the pigment particles was more significant in DEG because the total ion concentration (> 2000 ppm) was higher than that of the aqueous medium (> 200 ppm). The colour stability of the V-ZrSiO4 powder deteriorates as a consequence of an insufficient chemical stability both in the water and DEG media. Additionally, the V-ZrSiO4 particles dissolve with proton-promoted and hydroxyl-promoted dissolution mechanisms in the aqueous medium, whereas these particles dissolve with a ligand-promoted dissolution mechanism in the non-aqueous medium, TUBITAK Research Foundation [107M366]; Turkish Academy of Sciences through the TUBA-GEBIP (Outstanding Young Investigator) Programme, We would like to thank the programme for the Scientific and Technological Research Projects by TUBITAK Research Foundation under the Contract number 107M366 for the support. One of the authors (Ender Suvaci) acknowledges the Turkish Academy of Sciences for their support of this study through the TUBA-GEBIP (Outstanding Young Investigator) Programme.

IEEE International Symposium on the Applications of Ferroelectric / Workshop on the Piezoresponse Force Microscopy (ISAF/PFM) -- JUL 21-25, 2013 -- Prague, CZECH REPUBLIC, WOS: 000336807100036, The template grain growth technique was used to synthesis textured 60BiFeO(3)-PbTiO3 (60:40BFPT) by using platelets of BaTiO3 as template. Synchrotron measurement clearly showed textured 60: 40BFPT. Moreover, in situ high energy synchrotron radiation was employed to investigate the influence of an external electric filed on crystallographic structure of mixed phase 60: 40BFPT. Application of an electric field >= 1 kV/mm resulted in phase transformation from mixed rhombohedral/tetragonal phases (approximate to 73.5% tetragonal / 26.5% rhombohedral) to predominately tetragonal phase (approximate to 95%) at applied field of 6 kV/mm., IEEE