DOCSLIB.ORG

Hydrothermal Crystal Growth of Piezoelectric Α-Quartz Phase of AO2 (A = Ge, Si) and MXO4 (M = Al, Ga, Fe and X = P, As): a Historical Overview

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hydrothermal Crystal Growth of Piezoelectric Α-Quartz Phase of AO2 (A = Ge, Si) and MXO4 (M = Al, Ga, Fe and X = P, As): a Historical Overview crystals Review Hydrothermal Crystal Growth of Piezoelectric α-Quartz Phase of AO2 (A = Ge, Si) and MXO4 (M = Al, Ga, Fe and X = P, As): A Historical Overview Olivier Cambon * and Julien Haines Institut Charles Gerhardt Montpellier, Centre National de la Recherche Scientifique, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, Montpellier 34095 Cedex 05, France; [email protected] * Correspondence: [email protected]; Tel.: +33-4-67-14-32-04 Academic Editors: Alain Largeteau and Mythili Prakasam Received: 19 November 2016; Accepted: 25 January 2017; Published: 4 February 2017 Abstract: Quartz is the most frequently used piezoelectric material. Single crystals are industrially grown by the hydrothermal route under super-critical conditions (150 MPa-623 K). This paper is an overview of the hydrothermal crystal growth of the AO2 and MXO4 α-quartz isotypes. All of the studies on the crystal growth of this family of materials enable some general and schematic conclusions to be made concerning the influence of different parameters for growing these α-quartz-type materials with different chemical compositions. The solubility of the material is the main parameter, which governs both thermodynamic parameters, P and T, of the crystal growth. Then, depending on the chemistry of the α-quartz-type phase, different parameters have to be considered with the aim of obtaining the basic building units (BBU) of the crystals in solution responsible for the growth of the α-quartz-type phase. A schematic method is proposed, based on the main parameter governing the crystal growth of the α-quartz phase. All of the crystal growth processes have been classified according to four routes: classical, solute-induced, seed-induced and solvent-induced crystal growth. Keywords: hydrothermal crystal growth; α-quartz isotypes; basic building units (BBU) of the crystal; nucleation; homo-epitaxy; hetero-epitaxy; solute; seed; solvent 1. Introduction Hydrothermal growth is a natural process and occurs in the Earth’s crust. Originally, this term was used to describe the dissolution of rocks and minerals by water, under elevated pressures and temperatures, and the crystallization of various inorganic phases. Beryl, calcite, and quartz are the well-known large crystals, which are extracted from the Earth. Due to the interest in such materials, the hydrothermal technique was used to produce industrially synthetic materials, like quartz, for electronic applications [1,2]. Synthetic beryl and calcite single crystals have also been grown hydrothermally [3–6]. The term hydrothermal is now used to describe crystallization processes using aqueous solvents in a closed vessel. Based on this approach, sub- or super-critical conditions have been used in the vessel, depending on the solvent. This paper presents a review of the hydrothermal synthesis of the α-quartz IV III V phase in A O2 (A = Si, Ge) and M X O4 (M = Al, Ga and X = P, As) compounds. The α-quartz type structure belongs to the P3121 or P3221 space group. AO4 (A = Si and/or Ge for SiO2, GeO2 or Si1−xGexO2), MO4, and XO4 (for MXO4) tetrahedral units are connected, forming a helical chain along the c axis (Figure1). The α-quartz phase is stable at room temperature for all of the compounds except for GeO2, for which the α-quartz phase is stable at high temperatures from 1306 K up to the melting point at 1388 K (Table1): the α-quartz-type phase of GeO2 is a thermodynamic metastable phase at Crystals 2017, 7, 38; doi:10.3390/cryst7020038 www.mdpi.com/journal/crystals Crystals 2017, 7, 38 2 of 13 Crystals 2016, 6, 38 2 of 12 room temperature. The stable phase of GeO2 under ambient conditions is a rutile-type phase, in which phasethe germanium at room temperature. is 6-fold coordinated. The stable phase of GeO2 under ambient conditions is a rutile-type phase, in which the germanium is 6-fold coordinated. MXO4 AO2 2c c A O Figure 1. α-quartz structure of AO2 (A = Si, Ge) and MXO4 (M = Al, Ga, Fe and X = P, As) materials. Figure 1.α-quartz structure of AO2 (A = Si, Ge) and MXO4 (M = Al, Ga, Fe and X = P, As) materials. Table 1. Polymorphism of the AO2 and MXO4 materials. Table 1. Polymorphism of the AO2 and MXO4 materials. CompoundCompound Phase Phase Transitions Transitions 846 K 870 K 1673 K 1983 K SiO ⎯846⎯⎯ K→ ⎯870⎯⎯ K→ ⎯1673⎯⎯ K→ 2 α-Quartzα-Quartz ←⎯ −−−−−!−−−−− ⎯⎯β -Quartzβ-Quartz −−−−−!−−−−− ←⎯Tridymite ⎯⎯ Tridymite −−−−−!−−−−− β -Cristobalite←⎯ ⎯⎯ −−−−−! −−−−−β-Cristobaliteliquid SiO2 1306 K 1388 K GeO2 β-Rutile −−−−−!−−−−−⎯⎯⎯1983 Kα→-Quartz −−−−−!−−−−− Liquid 859 K 1088←⎯ K ⎯⎯ liquid1298 K 1870 K AlPO4 α-Quartz −−−−−! β-Quartz −−−−−! Tridymite −−−−−! β-Cristobalite −−−−−! liquid −−−−− ⎯⎯⎯1306 −−−−− K→ −−−−−⎯⎯⎯1388 K→ −−−−− GeO2 ←⎯ ⎯⎯980 K ←⎯1513 K ⎯⎯ FePO4 β-Rutileα -Quartz −−−−−!−−−−− α-Quartzβ-Quartz −−−−−!−−−−− Liquid Liquid ⎯859⎯⎯ K→ 1206⎯ K 1088⎯⎯ K→ 1943 K ⎯1298⎯⎯ K→ GaPO4 α-Quartz ←⎯ ⎯⎯ α -Quartzβ-Quartz −−−−−!−−−−− ←⎯β ⎯-Cristobalite⎯ Tridymite −−−−−!−−−−− ←⎯Liquid ⎯⎯ β-Cristobalite AlPO4 1303 K GaAsO4 α-Quartz −−−−−!⎯⎯⎯−−−−−1807 K→Chemical decomposition ←⎯ ⎯⎯ liquid ⎯⎯⎯980 K→ ⎯⎯⎯1513 K→ 2. HydrothermalFePO4 Crystal Growthα-Quartz ←⎯ ⎯⎯ β-Quartz ←⎯ ⎯⎯ Liquid ⎯1206⎯⎯ K→ ⎯1943⎯⎯ K→ GaPOFollowing4 the initial workα of-Quartz Gibbs [7←⎯] in 1878, ⎯⎯ and β-Cristobalite then that of Frenkel←⎯ ⎯ [⎯8] in Liquid 1945, Burton, Cabrera, and Frank [9,10] studied the growth of a real crystal⎯⎯⎯1303 K from→ the vapor phase. Thermodynamic equations GaAsO4 α-Quartz ←⎯ ⎯⎯ Chemical decomposition have been established, which describe the crystal growth from a structural defect, like a screw-type dislocation. Numerous authors [11–13] have applied this theory to growth from solution. Cabrera and 2. Hydrothermal Crystal Growth Levine [14] extended this approach to dissolution, which is the reverse phenomenon with respect to crystalFollowing growth. the All ofinitial these work studies of Gibbs were reconsidered[7] in 1878, and by Johnstonthen that inof 1962 Frenkel [15]. [8] Basically, in 1945, in Burton, crystal Cabrera,growth from and solution,Frank [9,10] the solutestudied crystallizes the growth when of a real the concentrationcrystal from the of thevapor solute phase. becomes Thermodynamic higher than equationsthe concentration have been at equilibrium, established, termedwhich describe solubility. th Thee crystal solubility growth is the from main a structural parameter defect, for growing like a screw-typecrystals from dislocation. solutions. HydrothermalNumerous authors crystal [11–13] growth ha correspondsve applied this to crystaltheory growthto growth from from solution solution. in a Cabreraclosed vessel. and Levine Temperature [14] extended and pressure this approach are two important to dissolution, thermodynamic which is the parameters, reverse phenomenon which have withto be respect adjusted to according crystal growth. to the solventAll of these used. st Theudies first were step reconsidered is to find the adequateby Johnston thermodynamic in 1962 [15]. Basically,conditions in for crystal obtaining growth a good from reactivity solution, ofthe the solute solvent crystallizes with the when solute. the Then, concentration for growing of crystalsthe solute of becomeshigh quality, higher the than experimental the concentration conditions at have equilibriu to be adjustedm, termed to solubility. modify the The kinetics solubility of the is exchanges the main parameterbetween the for solid growing phase crystals and the from solvent. solutions. By using Hydrothermal hydrothermal crystal techniques, growth thermodynamic-stablecorresponds to crystal growthand metastable from solution phases canin bea grown.closed Thevessel. main Temperature experimental and parameters, pressure which are cantwo beimportant adjusted thermodynamicare the solvent, theparameters, presence orwhich absence have of to a be nucleus adjusted (or according seed) and bothto the thermodynamic solvent used. The parameters, first step isP andto find T. the adequate thermodynamic conditions for obtaining a good reactivity of the solvent with the solute.One of Then, the mostfor growing important crystals questions, of high whichquality, has the to experimental be solved before conditions starting have a hydrothermalto be adjusted process,to modify is thethe choicekinetics of of which the pressureexchanges domain between the the crystal solid growth phase process and the will solvent. be performed By using in. Tohydrothermal answer to thistechniques, question, thermodynamic-stable the ability of the solvent and metastable to dissolve phases the chemical can be precursorsgrown. The and main to experimental parameters, which can be adjusted are the solvent, the presence or absence of a nucleus (or seed) and both thermodynamic parameters, P and T. Crystals 2017, 7, 38 3 of 13 recrystallize the desired phase has to be considered. In a polar solvent like aqueous solutions, the dissolution process forms ionic species in solution and crystallization is due to the condensation of the ionic species to form a new crystal. In pure water (pH = 7), H+ and OH− species are present with a concentration of 10−7 M. IV 2.1. Hydrothermal Growth of A O2 (A = Si, Ge) In the Earth, crystal growth of quartz occurs in water, which acts as the solvent under hydrothermal conditions. In the supercritical state, water is more aggressive due to the decrease in its ionic product [16] and the growth of quartz single crystals can take place, but with very slow kinetics. For the industrial production of quartz crystals, sodium hydroxide
Load more

Recommended publications
  • Conventional and Microwave Hydrothermal Synthesis and Application of Functional Materials: a Review
    materials Review Conventional and Microwave Hydrothermal Synthesis and Application of Functional Materials: A Review Guijun Yang and Soo-Jin Park * Department of Chemistry, Inha University, 100 Inharo, Incheon 402-751, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-32-876-7234 Received: 5 March 2019; Accepted: 9 April 2019; Published: 11 April 2019 Abstract: With the continuous development and progress of materials science, increasingly more attention has been paid to the new technology of powder synthesis and material preparation. The hydrothermal method is a promising liquid phase preparation technology that has developed rapidly during recent years. It is widely used in many fields, such as the piezoelectric, ferroelectric, ceramic powder, and oxide film fields. The hydrothermal method has resulted in many new methods during the long-term research process, such as adding other force fields to the hydrothermal condition reaction system. These force fields mainly include direct current, electric, magnetic (autoclaves composed of non-ferroelectric materials), and microwave fields. Among them, the microwave hydrothermal method, as an extension of the hydrothermal reaction, cleverly uses the microwave temperature to compensate for the lack of temperature in the hydrothermal method, allowing better practical application. This paper reviews the development of the hydrothermal and microwave hydrothermal methods, introduces their reaction mechanisms, and focuses on the practical application of the two methods. Keywords: hydrothermal method; microwave hydrothermal method; functional materials; application 1. Introduction During the process of continuous development of materials science, the research and development of new processes for material preparation and synthesis has always been an important part. For a long time, researchers have been searching for a material synthesis method with limited pollution, easy operation, excellent product performance, and low production cost [1–3].
    [Show full text]
  • Observation of Quadrupole Helix Chirality and Its Domain Structure in Dyfe3(BO3)4
    ARTICLES PUBLISHED ONLINE: 6 APRIL 2014 | DOI: 10.1038/NMAT3942 Observation of quadrupole helix chirality and its domain structure in DyFe3(BO3)4 T. Usui1, Y. Tanaka2, H. Nakajima1, M. Taguchi2, A. Chainani2, M. Oura2, S. Shin2, N. Katayama3, H. Sawa3, Y. Wakabayashi1 and T. Kimura1* Resonant X-ray diraction (RXD) uses X-rays in the vicinity of a specific atomic absorption edge and is a powerful technique for studying symmetry breaking by motifs of various multipole moments, such as electric monopoles (charge), magnetic dipoles (spin) and electric quadrupoles (orbital). Using circularly polarized X-rays, this technique has been developed to verify symmetry breaking eects arising from chirality, the asymmetry of an object upon its mirroring. Chirality plays a crucial role in the emergence of functionalities such as optical rotatory power and multiferroicity. Here we apply spatially resolved RXD to reveal the helix chirality of Dy 4f electric quadrupole orientations and its domain structure in DyFe3(BO3)4, which shows a reversible phase transition into an enantiomorphic space-group pair. The present study provides evidence for a helix chiral motif of quadrupole moments developed in crystallographic helix chirality. t is well known that chirality often plays a critical role in various detect not only crystallographic helix handedness but also the disciplines, such as biology, organic chemistry and particle chirality ascribed to the periodic motif of multipole moments, such Iphysics1,2. In contrast, chirality in solid-state physics, which as magnetic dipoles and electric quadrupoles12–14. In the case of is largely concerned with crystals possessing periodic arrays of magnetic dipoles, the handedness of a `helical magnetic structure' atoms, has attracted less attention.
    [Show full text]
  • The 3 Hours-Hydrothermal Synthesis of High Surface Area Superparamagnetic Fe3o4 Core-Shell Nanoparticles (Esty Octiana Sari)
    The 3 Hours-Hydrothermal Synthesis of High Surface Area Superparamagnetic Fe3O4 Core-Shell Nanoparticles (Esty Octiana Sari) THE 3 HOURS-HYDROTHERMAL SYNTHESIS OF HIGH SURFACE AREA SUPERPARAMAGNETIC Fe3O4 CORE-SHELL NANOPARTICLES Esty Octiana Sari,Ahmad Fadli andAmunAmri Department of Chemical Engineering Riau University Jl. HR Subrantas KM 12,5 Panam, Pekanbaru 28293, Riau E-mail: [email protected] Received: 2 May 2017 Revised: 27 September 2017 Accepted: 4 October 2017 ABSTRACT THE 3 HOURS-HYDROTHERMAL SYNTHESIS OF HIGH SURFACE AREA SUPERPARAMAGNETIC Fe3O4 CORE-SHELL NANOPARTICLES. The monodisperse core-shell Fe3O4 nanoparticles have been successfully synthesized by short times (3 hours) hydrothermal method at 220 oC from FeCl3, citrate, urea and PEG.The as-synthesized samples have been characterized using X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM), Bruneur-Emmet-Teller (BET) surface area analyzer, and Vibrating Sample Magnetometer (VSM). The XRD result shows the as-synthesized products are pure Fe3O4. The TEM image shows the magnetite nanoparticles have monodisperse core-shell shape. The BET result shows the magnetite nanoparticles have 650.757 m2/g surface area. The hysteresis curve shows the magnetite nanoparticles exhibit super paramagnetic properties. This simple method obtained 60 nm core-shell Fe3O4 particles with super paramagnetic, high surface area as well as hydrophilic properties. Those properties are promising for various biomedical application. The advantages of simple and short times methods with high quality of product make this method very promising to be applied. Keywords: Core-shell, Hydrothermal method, Superparamagnetic, Nanoparticles ABSTRAK 3 JAM-SINTETIS HIDROTERMALNANOPARTIKELCORE-SHELLSUPERPARAMAGNETIK Fe3O4 DENGAN LUAS PERMUKAAN TINGGI. Nanopartikel monodispersi Fe3O4 berbentuk core-shell o telah berhasil disintesis dengan metode hidrothermal waktu singkat (3 jam) pada suhu 220 C dari FeCl3, sitrat, urea dan PEG.
    [Show full text]
  • V.Lelting and Transformation Remperatures of Mineral and \Llied Substances
    v.lelting and Transformation remperatures of Mineral and \llied Substances I F. c. KRACEK ONTRIBUTIONS TO GEOCHEMISTRY EOLOGICAL SURVEY BULLETIN 1144-D HTED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Abstract~------------------------------------------------------- 1 General discussion----------------------------------------------- 1 Acknowledgments____________________________________________ 3 General references _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 Elements ------------------------------------------------------- 4 Oxides---------------------------------------------------------- 10 Oxide systems involving A120 3 ------------------------------------ 13 Oxide systems exclusive of Al2o3• B 2o 3, Si02 --------------------- 14 Silicate systems, binary__________________________________________ 17 Silicate systems, ternary _________________________________________ 21 Silicate systems, quaternary and higher ________ ----- _______________ 30 Silicate systems, miscellaneous ___________________________________ 32 Carbonates------------------------------------------------------ 33 Systems, miscellaneous __________________________________________ 36 References------------------------------------------------------ 63 ILLUSTRATIONS Figure 1. The system FeO --------------------------------------
    [Show full text]
  • Transfers Young, Stephanie Lynne, Chalfont St
    The Journal of Gemmology2010 / Volume 32 / Nos. 1–4 The Gemmological Association of Great Britain The Journal of Gemmology / 2009 / Volume 31 / No. 5–8 The Gemmological Association of Great Britain 27 Greville Street, London EC1N 8TN T: +44 (0)20 7404 3334 F: +44 (0)20 7404 8843 E: [email protected] W: www.gem-a.com Registered Charity No. 1109555 Registered office: Palladium House, 1–4 Argyll Street, London W1F 7LD President: Prof. A. H. Rankin Vice-Presidents: N. W. Deeks, R. A. Howie, E. A. Jobbins, M. J. O'Donoghue Honorary Fellows: R. A. Howie Honorary Life Members: H. Bank, D. J. Callaghan, T. M. J. Davidson, J. S. Harris, E. A. Jobbins, J. I. Koivula, M. J. O'Donoghue, C. M. Ou Yang, E. Stern, I. Thomson, V. P. Watson, C. H. Winter Chief Executive Officer: J. M. Ogden Council: J. Riley – Chairman, A. T. Collins, S. Collins, B. Jackson, C. J. E. Oldershaw, L. Palmer, R. M. Slater Members’ Audit Committee: A. J. Allnutt, P. Dwyer-Hickey, J. Greatwood, G. M. Green, J. Kalischer Branch Chairmen: Midlands – P. Phillips, North East – M. Houghton, North West – J. Riley, Scottish – B. Jackson, South East – V. Wetten, South West – R. M. Slater The Journal of Gemmology Editor: Dr R. R. Harding Assistant Editor: M. J. O’Donoghue Associate Editors: Dr A. J. Allnutt (Chislehurst), Dr C. E. S. Arps (Leiden), G. Bosshart (Horgen), Prof. A. T. Collins (London), J. Finlayson (Stoke on Trent), Dr J. W. Harris (Glasgow), Prof. R. A. Howie (Derbyshire), E. A. Jobbins (Caterham), Dr J.
    [Show full text]
  • Synthetic Quartz Crystal
    Synthetic Quartz Crystal n Terms and Definitions Synthetic Quartz Crystal: A single crystal grown using the Right-handed and left-handed quartz crystals: Crystals are hydrothermal synthesis method. divided into two types: right-handed and left-handed. A As-Grown Quartz Crystal: A synthetic quartz crystal grown difference in optical rotation creates the 2 types, but their naturally with no processing. physical properties are identical. Therefore, by cutting at the Lumbered Quartz Crystal: A synthetic quartz crystal with the X correct angle, the difference does not affect the characteristics and Z surfaces processed according to specified dimensions of a crystal oscillator. Generally right-handed quartz crystals are and angles using a diamond wheel #80. used in manufacture. Y-bar Synthetic Quartz Crystal: A synthetic quartz crystal grown Zone: A zone with a crystal that has grown from a seed crystal at by using a bar-like seed crystal elongated in the Y-axis direction. its core. There are Z, +X, -X, and S zones. Z-plate Synthetic Quartz Crystal: A synthetic quartz crystal Infrared Absorption Coefficient α: This value measured with an grown by using a plate-like seed crystal with a Y-axis direction infrared spectrophotometer is adopted as the infrared absorption length and X-axis direction width. coefficient α of a synthetic quartz crystal. The value is based on Inclusion: A general term for solid constituents (inclusions) that the absorption characteristic of the OH radical of a synthetic exist in synthetic quartz crystal; they can be observed when light quartz crystal that is around 3,800 to 3,000 cm–1 of the infrared is scattered through a liquid with a refractive index that is close transmittance curve.
    [Show full text]
  • Minerals from the Cioclovina Cave, Romania: a Review
    Studia Universitatis Babeş-Bolyai, Geologia, 2007, 52 (2), 3 - 10 High-temperature and “exotic” minerals from the Cioclovina Cave, Romania: a review Bogdan P. ONAC1,2 *, Herta S. EFFENBERGER3 & Radu C. BREBAN4 1 Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL 33620, USA 2 Department of Mineralogy, „Babeş-Bolyai“ University, Kogălniceanu 1, 400084 Cluj Napoca, Romania „Emil Racoviţă“ Institute of Speleology, Clinicilor 5, 400006 Cluj Napoca, Romania 3 Institut für Mineralogie und Kristallographie, Universität Wien, Althanstraße 14, 1090 Wien, Austria 4 SpeleoClub “Proteus”, Aleea Pescarilor, Bl. 30/47, Deva, Hunedoara, Romania Received November 2006; accepted February 2007 Available online 17 August 2007 ABSTRACT. This paper reports on the identification of four rare minerals in the phosphate deposit in Cioclovina Cave, Romania. Berlinite, AlPO4 and hydroxylellestadite, Ca5[(Si,P,S)O4]3(OH,F,Cl) are minerals that can form only at high temperatures, and would not be expected in a sedimentary environment. In this study we review the characteristics of berlinite and hydroxylellestadite from a heated sedimentary sequence in Cioclovina Cave (Romania) and refine their structure from single-crystal X-ray data. Two other minerals, churchite-(Y), YPO4⋅2H2O and foggite, CaAl(PO4)(OH)2⋅H2O are, for the first time, described from a cave environment. The minerals were documented by means of single-crystal X-ray investigations, X-ray powder diffraction, and electron-microprobe (EMPA) analyses. In addition, laboratory synthesis of berlinite was conducted and vibrational spectroscopy data were collected for hydroxylellestadite and churchite-(Y). Based on these investigations, we suggest that locally the heavily compacted phosphate-bearing clay sediments underwent a natural heating process.
    [Show full text]
  • Large-Scale Synthesis Route of Tio2 Nanomaterials with Controlled Morphologies Using Hydrothermal Method and Tio2 Aggregates As Precursor
    nanomaterials Article Large-Scale Synthesis Route of TiO2 Nanomaterials with Controlled Morphologies Using Hydrothermal Method and TiO2 Aggregates as Precursor Wenpo Luo 1 and Abdelhafed Taleb 1,2,* 1 Institut de Recherche de Chimie Paris, PSL Research University Chimie ParisTech—CNRS, 75005 Paris, France; [email protected] 2 Sorbonne Université, 75231 Paris, France * Correspondence: [email protected]; Tel.: +33-1-85-78-41-97 Abstract: TiO2 of controlled morphologies have been successfully prepared hydrothermally using TiO2 aggregates of different sizes. Different techniques were used to characterize the prepared TiO2 powder such as XRD, XPS, FEGSEM, EDS, and HRTEM. It was illustrated that the prepared TiO2 powders are of high crystallinity with different morphologies such as nanobelt, nanourchin, and nanotube depending on the synthesis conditions of temperature, time, and additives. The mechanism behind the formation of prepared morphologies is proposed involving nanosheet intermediate formation. Furthermore, it was found that the nanoparticle properties were governed by those of TiO2 nanoparticles aggregate used as a precursor. For example, the size of prepared nanobelts was proven to be influenced by the aggregates size used as a precursor for the synthesis. Keywords: TiO2 nanoparticles; aggregates; morphologies Citation: Luo, W.; Taleb, A. Large-Scale Synthesis Route of TiO2 Nanomaterials with Controlled Morphologies Using Hydrothermal 1. Introduction Method and TiO2 Aggregates as Recently, tremendous efforts have been devoted to developing innovative strategies Precursor. Nanomaterials 2021, 11, 365. to synthesize nanomaterials with the desired morphologies and properties. Particularly https://doi.org/10.3390/ the one-dimensional (1D) structure of TiO2 nanomaterials exhibits interesting properties nano11020365 compared to other TiO2 nanoparticles: it has lower carrier recombination rate and higher charge carrier mobility, thanks to the grain boundaries and junctions absence.
    [Show full text]
  • Trace Elements and Growth Patterns in Quartz: a Fingerprint of the Evolution of the Subvolcanic Podlesí Granite System (Krušné Hory Mts., Czech Republic)
    Bulletin of the Czech Geological Survey, Vol. 77, No. 2, 135–145, 2002 © Czech Geological Survey, ISSN 1210-3527 Trace elements and growth patterns in quartz: a fingerprint of the evolution of the subvolcanic Podlesí Granite System (Krušné hory Mts., Czech Republic) AXEL MÜLLER1 – ANDREAS KRONZ2 – KAREL BREITER3 1Natural History Museum, Dept. Mineralogy, Cromwell Road, London SW7 5BD, United Kingdom; e-mail: [email protected] 2Geowissenschaftliches Zentrum Göttingen, Goldschmidtstr. 1, D-37077 Göttingen, Germany 3Czech Geological Survey, Geologická 6, 152 00 Praha 5, Czech Republic Abstract. The Podlesí Granite System (PGS) in the Western Krušné hory Mts., Czech Republic, represents a suite of late-Variscan, highly frac- tionated rare-metal granites. Based on textural studies and cathodoluminescence five igneous quartz populations can be distinguished in the stock gran- ite and the more evolved dyke granite hosting line rocks (layered granites). Trace element profiling by electron probe micro-analysis (EPMA) gives evidence for three main crystallisation stages: (1) the zoned quartz phenocrysts representing the early stage of magma evolution in the middle crust, (2) the stockscheider quartz and groundmass quartz of the stock granite reflecting the subvolcanic solidification conditions of the stock granite, and (3) the zoned snowball quartz and comb quartz of the dyke granite crystallised from a highly evolved, residual melt. Ti and Al in quartz show a gen- eral temporal trend reflecting the evolution of the magma: decrease of Ti and increase of Al. The increase of lithophile elements (Li, Na, Al, P, K) and of the water content in the magma, the decrease of Ti, crystallisation temperature and pressure are assumed to be predominantly responsible for the trend.
    [Show full text]
  • Module 8 Unit-3 NSNT Hydrothermal Synthesis Hydrothermal
    Module 8_Unit-3_NSNT Hydrothermal Synthesis Hydrothermal processing has gained much interest for synthesizing advanced nanomaterials as well as composites exhibiting tailored properties. This technique has been used to produce nanostructured materials for a broad range of applications which include electronics and optoelectronic devices, catalysis, biomedicine, biophotonics, etc. The word ‘hydrothermal’ has its origin in geology and Sir Roderick Murchison, a British geologist, was the first to use it. He attributed the variations in earth’s crust and the subsequent forming rocks as well as minerals to hydrothermal action of water at very high temperatures and pressures. Incidentally, the largest naturally occurring single crystal (beryl crystal, more than 1kg), as well as the largest man-made single crystal (quartz crystal, of several kgs), both have originated via hydrothermal process [1-2]. Hydrothermal synthesis belongs to a group of syntheses techniques in which substances in high- temperature and high pressure aqueous solution are crystallized. This is also called as the “hydrothermal method” [1]. According to Byrappa [3], hydrothermal processing is “any heterogeneous chemical reaction in the presence of a solvent (aqueous or non-aqueous) above room temperature and at pressures > 1 atm in a closed system” [2]. Hydrothermal processing includes techniques such as hydrothermal synthesis, hydrothermal crystal growth, hydrothermal transformation, hydrothermal sintering, etc. Hydrothermal processing of nanomaterials yields highly pure, homogenous, symmetrical crystal structures having novel properties. It also allows greater size control, low temperature synthesis, more control over composition of the end product, dense compounds, and can be used to produce compounds in relatively short time durations. Hydrothermal is a solution processing technique which involves processing of super heated aqueous solutions.
    [Show full text]
  • Crystal Structure Transformations in Inorganic Sulfates, Phosphates, Perchlorates, and Chromates Based on the Literature up to 1974
    A111D1 ^65756 NATL INST OF STANDARDS & TECH R. .C. All 101 985758 Rao C. N. R. (Chlnt/Crystal structure t 4 A50.R28 1975 C.1 NSRDS 1975 NSRDS % Of U.S. DEPARTMENT OF COMMERCE National Bureau of Standards " / ' ' N N SRD S Crystal Structure Transformations in Inorganic Sulfates, Phosphates, Perchlorates, and Chromates NATIONAL BUREAU OF STANDARDS The National Bureau of 1 Standards was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation’s science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Institute for Computer Sciences and Technology, and the Office for Information Programs. iHE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation’s scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, the Office of Radiation Measurement and the following Center and divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical .Physics — Center for Radiation Research: Nuclear Sciences; Applied Radiation — Laboratory Astrophysics 2 — Cryogenics 2 — Electromagnetics 2 2 — Time and Frequency .
    [Show full text]
  • Synthesis and Application of Two Dimensional Non- Layered Nanomaterials Derived from Liquid Gallium
    Synthesis and application of two dimensional non- layered nanomaterials derived from liquid gallium A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Nitu Syed M.Sc. (Electrical and Electronic Engineering), Bangladesh University of Engineering and Technology B. Sc. (Electrical and Electronic Engineering), Bangladesh University of Engineering and Technology School of Engineering College of Science, Engineering and Health RMIT University August 2019 Declaration I certify that except where due acknowledgement has been made, the work is that of the author alone; the work has not been submitted previously, in whole or in part, to qualify for any other academic award; the content of the thesis is the result of work which has been carried out since the official commencement date of the approved research program; any editorial work, paid or unpaid, carried out by a third party is acknowledged; and, ethics procedures and guidelines have been followed. I acknowledge the support I have received for my research through the provision of an Australian Government Research Training Program Scholarship. Nitu Syed 15/08/2019 ii Acknowledgements First and foremost, I would like to thank the almighty Allah to be the most gracious and merciful all through my life. I gratefully acknowledge the funding provided by RMIT University for awarding me with Vice-Chancellor's PhD Scholarship (VCPS) and School of Engineering for the top up scholarship. I would like to appreciate the support provided by Australian Research Council (ARC) and Centre for future low-energy electronics technologies (FLEET) for giving me the opportunity to participate in several valuable educational programs.
    [Show full text]