Hydrothermal Synthesis and Study of the Properties of the System ZrW2-xMoxO7(OH)2·2H2O (0≤x≤2)

2019 ◽  
Vol 806 ◽  
pp. 118-123 ◽  
Author(s):  
Mariya Yu. Petrushina ◽  
Elena Dedova ◽  
Alexander Gubanov ◽  
Natalya Ruban ◽  
Anastasya Kirilovich ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Hydrothermal Synthesis ◽  
Oil And Gas ◽  
Hydrothermal Reaction ◽  
Coefficient Of Thermal Expansion ◽  
Synthesis Process ◽  
Property A ◽  
Technical Problems ◽  
Nanosized Materials ◽  
Lower Temperature

The ZrW2-xMoxO8 (0≤x≤2) system has a unique property - a negative coefficient of thermal expansion (CTE), that is it shrinks when heated. Such materials solve the problem of undesirable thermal expansion of composites in many areas. In contradistinction to ZrW2O8 and ZrMo2O8, this system has anomalously low CTE values [1,2] and adverse phase transition is shifted to a lower temperature, unlikely area for operation [3,4]. At the same time, the fundamental question remains about the mechanism of formation of ZrW2-xMoxO8(0≤x≤2). According to [5,6], pure cubic ZrW2O8 and ZrMo2O8 are obtained by thermal decomposition of the precursor ZrM2O7(OH)2· 2H2O, where (M = Mo, W). However, the structure of the precursor is extremely sensitive to various changes in the synthesis process. To date, there are a number of works devoted to the hydrothermal synthesis of precursors ZrW2-xMoxO7(OH)2·2H2O (0≤x≤2) solid solutions, however, not all formulations were obtained during the hydrothermal reaction. The study of their thermal properties, as well as structural and phase transformations are not fully studied. Within the paper it was first time proposed to obtain full number of nanosized materials by the hydrothermal method and also to study the nature of the thermal expansion of each member of the solid solution. The obtained data will solve many technical problems associated with dimensional nonvariance in the electronic, oil and gas, optical industry, medicine and rocket engineering.

Optimized Parameters for Synthesis of BaTiO3 Films With High Electromechanical Coupling

2016 ◽  
Author(s):  
Zhi Zhou ◽  
Christopher C. Bowland ◽  
Brendan A. Patterson ◽  
Mohammad H. Malakooti ◽  
Henry A. Sodano
Keyword(s):  
Hydrothermal Synthesis ◽  
Electromechanical Coupling ◽  
Hydrothermal Reaction ◽  
Ferroelectric Properties ◽  
Past Research ◽  
Synthesis Process ◽  
Hydrothermal Processing ◽  
A Value ◽  
Batio3 Film ◽  
Synthesis Of Barium Titanate

This research improves upon prior research efforts on the hydrothermal synthesis of barium titanate (BaTiO3) films. It has been established that BaTiO3 can be synthesized using a two-step hydrothermal reaction that first synthesizes TiO2 then converts it to BaTiO3. Past research, however, resulted in relatively low ferroelectric properties using this technique. The research addresses that shortcoming by offering an optimized hydrothermal synthesis process that significantly increase the electromechanical coupling of the BaTiO3 film. Here, it is shown that the d33 achieves a value of 80 pm/V, which is the bulk BaTiO3 value. Additionally, this optimization results in an enhanced dielectric constant of 1600. Therefore, this research reveals that the ferroelectric properties of a hydrothermally synthesized BaTiO3 film can be significantly enhanced through slight modifications in the hydrothermal processing procedure.

Thermo-physical properties of nonlinear optical crystal K3B6O10Br

2016 ◽  
Vol 49 (2) ◽  
pp. 539-543 ◽  
Author(s):  
Mingjun Xia ◽  
Bo Xu ◽  
Lijuan Liu ◽  
Xiaoyang Wang ◽  
Rukang Li ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Physical Properties ◽  
Specific Heat ◽  
Nonlinear Optical ◽  
Coefficient Of Thermal Expansion ◽  
Second Harmonic ◽  
Damage Threshold ◽  
Thermal Expansion Coefficients ◽  
Lower Temperature ◽  
Thermo Physical Properties

The thermo-physical properties of the nonlinear optical (NLO) crystal K3B6O10Br (KBB) were experimentally investigated, including specific heat, thermal conductivity, coefficient of thermal expansion and refractive index. The specific heat of KBB is lower than that of LiB3O5 and higher than that of other borate NLO crystals, such as β-BaB2O4, CsLiB6O10 and CsB3O5, and KBB manifests a high damage threshold because of its lower temperature gradient during laser pulse irradiation. The thermal expansion coefficients were obtained as α x = 5.09 × 10−6 K−1 and α z = 2.39 × 10−5 K−1, showing weaker anisotropy than those of commonly used NLO crystals. The temperature-dependent Sellmeier dispersion equations of the refractive indices were also obtained, and the phase-matching angles for second harmonic generation (SHG) at temperatures of 313, 343, 373, 403 and 433 K which were calculated from these equations are in good agreement with the experimental values. All results are indicative of the KBB crystal as a novel promising NLO crystal for high power SHG.

scholarly journals The preparation of dental glass-ceramic composites with controlled fraction of leucite crystals

2008 ◽  
Vol 2 (1) ◽  
pp. 23-26
Author(s):  
Martina Mrázová ◽  
Alexandra Klouzková ◽  
Martin Pallich ◽  
Martinac Kohoutková
Keyword(s):  
Thermal Expansion ◽  
Hydrothermal Synthesis ◽  
Thermal Treatment ◽  
Coefficient Of Thermal Expansion ◽  
Ceramic Composites ◽  
Raw Material ◽  
Dental Composites ◽  
Prepared Composite ◽  
Average Size ◽  
Matrix Powder

This work is dealing with synthesis of leucite powder, which can be used for the preparation of dental glassceramic composites by subsequent thermal treatment. Newly developed procedure is based on preparation of dental raw material as a mixture of two separate compounds: the crystalline leucite powder prepared at relatively low temperature and a commercial matrix powder. Hydrothermal synthesis of tetragonal leucite particles (KAlSi2O6) with the average size of about 3 ?m was developed in our laboratory. The leucite dental raw material was prepared by mixing of 20 wt.% of synthetic tetragonal leucite with commercial matrix. Dental composites were prepared from the dental raw material by uniaxial pressing and firing up to 960?C. Dilatometric measurements confirmed that the coefficient of thermal expansion increased by 32% when 20 wt.% of the tetragonal leucite was added into the basic matrix. In addition, it was showed that the synthesized leucite powder was suitable for the preparation of leucite composites with controlled coefficient of thermal expansion. High value of the thermal expansion coefficient enables application of prepared composite in metal-ceramics restorations.

Selective synthesis of nanosized TiO2 by hydrothermal route: Characterization, structure property relation, and photochemical application

2004 ◽  
Vol 19 (9) ◽  
pp. 2567-2575 ◽  
Author(s):  
K. Madhusudan Reddy ◽  
Debanjan Guin ◽  
Sunkara V. Manorama ◽  
A. Ramachandra Reddy
Keyword(s):  
Hydrothermal Reaction ◽  
Visible Spectrum ◽  
Blue Shift ◽  
Rutile Phase ◽  
Photochemical Activity ◽  
Synthesis Process ◽  
Structure Property ◽  
Hydrothermal Route ◽  
Lower Temperature ◽  
Average Size

By variation of reaction temperature and time during the hydrothermal synthesis process, TiO2 nanoparticles in anatase, rutile, and mixture of rutile-anatase phases are formed without adding any mineralizer. Differential thermal analysis studies indicate the rutile phase crystallization at a comparatively lower temperature and a low weight loss. The material synthesized by hydrothermal reaction required no post-calcination for the crystallization. Transmission electron microscopy, selected-area diffraction, Brunauer–Emmett–Teller, and x-ray diffreaction studies confirmed the compositions to be anatase and rutile with the particle size ranging from 5 to 25 nm with surface area as high as 260 m2/g for the anatase and 65 m2/g for rutile. The prepared nanoparticles exhibited a blue shift of the absorption edge in the ultraviolet-visible spectrum greater than 10 nm. The particles with average size around 5 nm showed two band edges in the absorption spectra attributed to two different particle sizes. Simple photocatalytic reactions were tried to demonstrate the photochemical activity of the synthesized material. The synthesized nanoparticles exhibited an ultraviolet radiation simultaneous photoreduction of Cr(VI) to Cr(III) and oxidation of formic acid into carbon dioxide and water.

NILO ALLOY 36

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Constant Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Iron Nickel

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..

UNISPAN LR35

Alloy Digest ◽  
1971 ◽  
Vol 20 (1) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance ◽  
Operational Level

Abstract UNISPAN LR35 offers the lowest coefficient of thermal expansion of any alloy now available. It is a low residual modification of UNISPAN 36 for fully achieving the demanding operational level of precision equipment. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and surface treatment. Filing Code: Fe-46. Producer or source: Cyclops Corporation.

DELTALLOY 4032

Alloy Digest ◽  
1998 ◽  
Vol 47 (4) ◽  
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Surface Finish ◽  
Coefficient Of Thermal Expansion ◽  
Single Point ◽  
High Strength ◽  
Corrosion And Wear

Abstract Deltalloy 4032 has good machinability and drilling characteristics when using single-point or multispindle screw machines and an excellent surface finish using polycrystalline or carbide tooling. The alloy demonstrates superior wear resistance and may eliminate the need for hard coat anodizing. Deltalloy 4032 is characterized by high strength and a low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion and wear resistance as well as machining and surface treatment. Filing Code: AL-347. Producer or source: ALCOA Wire, Rod & Bar Division.

RED X-20

Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Aluminum Silicon Alloy ◽  
Temperature Performance

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.

AA 4032

Alloy Digest ◽  
1990 ◽  
Vol 39 (7) ◽  
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Coefficient Of Thermal Expansion ◽  
Heat Treating ◽  
Temperature Performance

Abstract AA 4032 has a comparatively low coefficient of thermal expansion and good forgeability. The alloy takes on an attractive dark gray appearance when anodized which may be desirable in architectural applications. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-305. Producer or source: Various aluminum companies.

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