ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Low-Temperature Sintering of β-Spodumene Ceramics Using Li2O–GeO2 as a Sintering Additive (2013)
    Wiley
    Details
    Publication Date: 2013-06-06
    Description: Low-temperature sintering of β-spodumene ceramics with low coefficient of thermal expansion (CTE) was attained using Li 2 O – GeO 2 sintering additive. Single-phase β-spodumene ceramics could be synthesized by heat treatment at 1000°C using highly pure and fine amorphous silica, α-alumina, and lithium carbonate powders mixture via the solid-state reaction route. The mixture was calcined at 950°C, finely pulverized, compacted, and finally sintered with or without the sintering additive at 800°C–1400°C for 2 h. The relative density reached 98% for the sample sintered with 3 mass% Li 2 O – GeO 2 additive at 1000°C. Its Young's modulus was 167 GPa and flexural strength was 115 MPa. Its CTE (from R.T. to 800°C) was 0.7 × 10 −6  K −1 and dielectric constant was 6.8 with loss tangent of 0.9% at 5 MHz. These properties were excellent or comparative compared with those previously reported for the samples sintered at around 1300°C–1400°C via melt-quenching routes. As a result, β-spodumene ceramics with single phase and sufficient properties were obtained at about 300°C lower sintering temperature by adding Li 2 O – GeO 2 sintering additive via the conventional solid-state reaction route. These results suggest that β-spodumene ceramics sintered with Li 2 O – GeO 2 sintering additive has a potential use as LTCC for multichip modules.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Two-Dimensional Orientation in Bi4Ti3O12 Prepared Using Platelet Particles and a Magnetic Field (2013)
    Wiley
    Details
    Publication Date: 2013-03-01
    Description: Tailoring the crystallographic orientation in piezoelectric ceramics is very useful for improving their properties. Orientation in ceramics can be controlled by templated grain growth, hot forging, etc. We have focused on using a strong magnetic field for the crystallographic orientation even in diamagnetic ceramics. In a previous study, although only a one-directional orientation could be controlled by these methods, it was difficult to control the multi-axis orientation in the ceramics. In this study, we demonstrated that alignments of the c -axis and the 〈100〉 axis in Bi 4 Ti 3 O 12 piezoelectric ceramics were controlled by using a strong magnetic field as well as platelet particles. We also estimated the degree of orientation by an electron back scattering diffraction analysis. When the magnetic field was applied to the platelet particles, appropriately 80% of the grains were aligned with the tilt angle made by the c -axis and the vertical direction less than 10° and 73% of grains were oriented with the angle between the 〈100〉 axis and the magnetic field less than 10°.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Preparation of Platelike NaNbO3 Particles by Single-Step Molten Salt Synthesis (2012)
    Wiley
    Details
    Publication Date: 2012-04-15
    Description: This article reports single-step molten salt synthesis to prepare single-crystal, platelike NaNbO 3 particles without the Bi 2 O 3 byproduct. In the previous method of two-step molten salt synthesis, platelike Bi 2.5 Na 3.5 Nb 5 O 18 particles have been prepared by heating a mixture of Bi 2 O 3 , Na 2 CO 3 , and Nb 2 O 5 in molten NaCl ; the particles are then converted to platelike NaNbO 3 particles by reaction with Na 2 CO 3 in molten NaCl . The obtained NaNbO 3 particles are polycrystalline, and Bi 2 O 3 particles form as a byproduct. In the present method, single-crystal, platelike NaNbO 3 particles without the Bi 2 O 3 byproduct are obtained by heating mixtures of Bi 2 O 3 , Na 2 CO 3 , and Nb 2 O 5 with molar ratios of 5:7:10 (the composition of Bi 2.5 Na 3.5 Nb 5 O 18 ) and 5:5:8 (the composition of Bi 2.5 Na 2.5 Nb 4 O 15 ) in molten NaCl at 1225°C for 12 h. During heating, platelike Aurivillius ( Bi 2.5 Na 3.5 Nb 5 O 18 and Bi 2.5 Na 2.5 Nb 4 O 15 ) particles are formed first and these then react with NaCl to form platelike NaNbO 3 particles, BiCl 3 , and Na 2 O . BiCl 3 evaporates from the system and Na 2 O is washed out after heating. Thus, single-phase NaNbO 3 is obtained. Sluggish conversion from the Aurivillius phases to NaNbO 3 is responsible for the formation of single-crystal particles.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Tailoring of Grain Size in Textured CaBi4Ti4O15 Ceramics Prepared by Templated Grain Growth Process (2012)
    Wiley
    Details
    Publication Date: 2012-08-18
    Description: To examine the effect of grain size on piezoelectric constant d 33 , textured CaBi 4 Ti 4 O 15 (CBT) and Mn -doped CBT ceramics were prepared with a special emphasis on the control of the grain size. The textured ceramics were prepared using the templated grain growth method. First, the mechanism of microstructure development was examined to design the method to control the grain size. It was found that the morphological change in the matrix grains in the presence of platelike template grains was the major origin of microstructure development. This suggested that the grain size in textured ceramics was determined by the template grain size. Then, textured ceramics with various grain sizes were prepared using template powders with various grain sizes. Finally, the effect of grain size on the value of d 33 was evaluated. It was found that the grain size had a small effect on the value of d 33 for textured CBT and Mn -doped CBT ceramics.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Low-Temperature Sintering of High-Strength β-Eucryptite Ceramics with Low Thermal Expansion Using Li2O–GeO2 as a Sintering Additive (2011)
    Wiley
    Details
    Publication Date: 2011-01-19
    Description: Low-temperature sintering of high-strength β-eucryptite ceramics with low positive coefficient of thermal expansion (CTE) was attained using Li 2 O–GeO 2 sintering additive. High-purity β-eucryptite could be synthesized using high-purity and fine amorphous silica, α-alumina, and lithium carbonate powder mixture at 950°C via the solid-state reaction route. Accordingly, the mixture was calcined at 900°C, pulverized, compacted, and sintered at 1020°C for 2 h with the sintering additive. The sintering temperature could be lowered by about 300°C, compared with the sintering temperature previously reported. The relative density of the sintered sample reached 99% of true density. Its flexural strength and indentation fracture toughness were 214 MPa and 2.5 MPa·m 1/2 , respectively. Its CTE (from room temperature to 800°C) was 1.2 × 10 –6 /K. Its dielectric constant was 5.5 with a loss tangent of 7.5 × 10 –3 . However, prolonged sintering time resulted in large negative CTE and mechanical weakness in the sintered samples. Microcracks were introduced with prolonged sintering time, which caused their large negative CTE with mechanical weakness.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Preparation and Characteristics of Bi0.5Na0.5TiO3 Single-Crystalline Films by a Solid-State Process (2011)
    Wiley
    Details
    Publication Date: 2011-05-03
    Description: A novel process was demonstrated for the preparation of an epitaxial Bi 0.5 Na 0.5 TiO 3 (BNT) single-crystalline film on a SrTiO 3 single crystal substrate by simply heating a composite consisting of a BNT powder layer on the substrate. The BNT powder layer was formed on the substrate by spin coating and the composite was heated at 1150°C for several hours in a lidded crucible containing the BNT powder to avoid evaporation of Na and Bi from the composite. This yielded an epitaxial BNT single-crystalline film several micrometers thick. The film had a high degree of orientation with the rocking curve full width at half maximum of 0.064°. The mechanism of film formation was found to be solid-state spreading of BNT powder particles on the substrate, and a dense film was obtained from the porous powder layer.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Preparation of Platelike NaNbO3 Particles by Single-Step Molten Salt Synthesis (2012)
    Wiley
    Details
    Publication Date: 2012-02-22
    Description: This article reports single-step molten salt synthesis to prepare single-crystal, platelike NaNbO 3 particles without the Bi 2 O 3 byproduct. In the previous method of two-step molten salt synthesis, platelike Bi 2.5 Na 3.5 Nb 5 O 18 particles have been prepared by heating a mixture of Bi 2 O 3 , Na 2 CO 3 , and Nb 2 O 5 in molten NaCl ; the particles are then converted to platelike NaNbO 3 particles by reaction with Na 2 CO 3 in molten NaCl . The obtained NaNbO 3 particles are polycrystalline, and Bi 2 O 3 particles form as a byproduct. In the present method, single-crystal, platelike NaNbO 3 particles without the Bi 2 O 3 byproduct are obtained by heating mixtures of Bi 2 O 3 , Na 2 CO 3 , and Nb 2 O 5 with molar ratios of 5:7:10 (the composition of Bi 2.5 Na 3.5 Nb 5 O 18 ) and 5:5:8 (the composition of Bi 2.5 Na 2.5 Nb 4 O 15 ) in molten NaCl at 1225°C for 12 h. During heating, platelike Aurivillius ( Bi 2.5 Na 3.5 Nb 5 O 18 and Bi 2.5 Na 2.5 Nb 4 O 15 ) particles are formed first and these then react with NaCl to form platelike NaNbO 3 particles, BiCl 3 , and Na 2 O . BiCl 3 evaporates from the system and Na 2 O is washed out after heating. Thus, single-phase NaNbO 3 is obtained. Sluggish conversion from the Aurivillius phases to NaNbO 3 is responsible for the formation of single-crystal particles.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    An Investigation of the Nanomechanical Properties of 0.5Ba(Ti0.8Zr0.2)O3–0.5(Ba0.7Ca0.3)TiO3 Thin Films (2014)
    Wiley
    Details
    Publication Date: 2014-09-27
    Description: For practical application, the functional piezoelectric film in microelectromechanical systems should meet the requirement of physical properties, as well as the mechanical properties. In this article, 0.5 Ba ( Ti 0.8 Zr 0.2 ) O 3 –0.5( Ba 0.7 Ca 0.3 ) TiO 3 (0.5BZT–0.5BCT) thin films with varied properties were prepared on (100) Si substrates via a sol–gel technique at different annealing temperatures. The effects of the annealing temperature on the morphology, piezoelectricity, hardness, and elastic modulus were studied. Particular attention was paid to the surface frictional behavior of films, and the changes in the friction force can be radically explained in terms of differences in the hardness/elastic modulus ratio and the residual stress of films. And, it reveals that the higher ratio of hardness to elastic modulus and tensile residual stress can contribute to a lower friction force for 0.5BZT–0.5BCT film during sling friction.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Influences of Temperature and Oxygen Partial Pressure on Mechanical Properties of La0.6Sr0.4Co1−yFeyO3−δ (2012)
    Wiley
    Details
    Publication Date: 2012-05-29
    Description: Young's and shear moduli and Poisson's ratio of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ ( LSCF 6428), La 0.6 Sr 0.4 Co O 3−δ ( LSC ), and La 0.6 Sr 0.4 FeO 3−δ ( LSF ) were investigated in the temperature range from room temperature to 1173 K and in the oxygen partial pressure, P ( O 2 ), range from 1 × 10 −1 to 1 × 10 −4  bar by the resonance method. The Young's and the shear moduli decreased with increasing temperature at low temperatures and drastically increased at intermediate temperatures. The drastic increase was associated with the second-order phase transition. In contrast, the Poisson's ratios of LSCF 6428, LSC , and LSF decreased around the phase transition temperature. The P ( O 2 ) dependence of the Young's and the shear moduli of LSCF 6428 showed different tendencies depending on temperature. At 873 K, the Young's and the shear moduli were almost independent of P ( O 2 ), whereas they increased with decreasing P ( O 2 ) at 973 K. At 1073 K, they first increased with decreasing P ( O 2 ) under higher P ( O 2 ) and then gradually decreased under lower P ( O 2 ). At 1173 K, they monotonically decreased with decreasing P ( O 2 ). Such complicated P ( O 2 ) dependence were interpreted by complex influences of the phase transition, the chemical expansion and the variation of the oxygen nonstoichiometry and the cation mean valence.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Role of Alumina in the Preparation of Platelike NaNbO3 Powder by Molten Salt Synthesis and Proposal of New Preparation Method (2013)
    Wiley
    Details
    Publication Date: 2013-05-23
    Description: The preparation of platelike NaNbO 3 grains via single-step molten salt synthesis using Bi 2 O 3 , Na 2 CO 3 , Nb 2 O 5 , and NaCl as reactants was examined. When a new alumina crucible was used, platelike NaNbO 3 grains were obtained, but a repeatedly used alumina crucible resulted in irregularly shaped NaNbO 3 grains. When a platinum crucible was used, even NaNbO 3 could not be obtained. Addition of alumina substrates and alumina granules to the reaction mixture in the platinum crucible resulted in the formation of platelike NaNbO 3 grains and second-phase grains. The second-phase grains, which were composed of Al 2 O 3 , Bi 2 O 3 , Na 2 O , and Nb 2 O 5 and had a pyrochlore structure, could be removed by sieving. The second phase acted as a scavenger for Bi 2 O 3 and hence, the possibility of using another scavenger was attempted. The new scavenger was a mixture of Na 2 CO 3 and Nb 2 O 5 , and using them, platelike NaNbO 3 grains were successfully obtained with NaNb 5 Bi 2 O 16 as a byproduct, which could then be removed by sieving.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...