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  • 1
    Electronic Resource
    Electronic Resource
    Analysis of aluminum tungsten oxide ceramics synthesized by a high-power cw CO2 laser (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 1616-1624 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ceramics in the Al2O3-WO3 system have been produced by laser irradiation. Examination of the products by scanning electron microscopy showed that a cell structure had formed in the specimens. A comparison of the properties of the samples synthesized by laser and by conventional sintering methods showed that the laser technique can produce new materials with some unique properties such as the linear decrease in resistivity of Al2O3-50 mol % WO3 specimens with increasing temperature over the range of 10–150 °C. X-ray photographic powder analysis indicated that the conducting phase in the specimen is a nonequilibrium product: AlxWO3 tungsten bronze.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354810
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  • 2
    Electronic Resource
    Electronic Resource
    Electrical Properties of Laser-Synthesized Aluminum Oxide-Tungsten Oxide Ceramics (1998)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 81 (1998), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Electronic ceramics of the Al2O3-WO3 system were synthesized by using a high-powered CO2 laser. It was shown that these ceramics can be used as linear thermistor materials. The linear temperature range of the Al2O3-WO3 system was ~200°C, the nonlinear deviation epsilon was 〈2%, the thermistor constant B was 〈103, and the temperature coefficient was between -0.2%/°C and -0.8%/°C. These parameters could be adjusted by changing the composition of the samples and the laser-synthesis parameters. The present study showed that the materials should be encapsulated if they are to be used in an oxidizing atmosphere. The current-voltage curves of the present materials were symmetrical around the coordinate origin, which also is a necessary condition for judging whether or not a thermistor is linear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02640.x
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  • 3
    Electronic Resource
    Electronic Resource
    Enthalpies of formation of some phases present in the Y−Ba−Cu−O system by solution calorimetry (1995)
    Springer
    Journal of solution chemistry 24 (1995), S. 565-578 
    Details
    ISSN: 1572-8927
    Keywords: Enthalpy of formation ; solution calorimetry ; superconductor ; Y−Ba−Cu−O system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Enthalpies of some of the phases in the Y−Ba−Cu−O system were determined by solution calorimetry using a Calvet microcalorimeter. The standard enthalpies of formation for the phases were found to be YBa2Cu3O6.60, −2627.9; YBa2Cu3O6.77, −2641.8; YBa2Cu3O6.90, −2652.0; YBa2Cu3O6.99, −2659.3; Y2Cu2O5, −2198.6; Y2BaCuO5, −2656.4; BaCuO2.33, −788.6; and BaCuO2.42, −796.2 kJ-mol−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973207
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  • 4
    Electronic Resource
    Electronic Resource
    Wear Properties of Y-TZP Ceramics Dispersed with Second Phase Particles (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 368-372 (Feb. 2008), p. 744-747 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The wear properties of ADZ (alumina dispersed in Y-TZP) and MDZ (mullite dispersed inY-TZP) were investigated by using a ring-on-block tribometer. The results showed that for Y-TZPceramic, the addition of alumina phase (with 10-20% in mass fraction) leads to an improved wearresistance. With the increase of the normal load, the wear rates of ADZ ceramics increase. Under low andmedium normal load (100N and 300N), the wear resistance is controlled by the hardness of ceramics, andunder high normal load (500N) the fracture toughness is obviously contributed to the wear resistance ofthe ceramics. For MDZ ceramic, the wear resistance of 15MDZ (15wt% mullite dispersed in Y-TZP) isbetter than that of 20 MDZ (20wt% mullite) under the normal load from 100 N to 500 N. The mechanicalproperties of 15MDZ are worse than that of Y-TZP ceramic, but the wear resistance is enhanced due tothe action of “needle roller bearing” of the fractured rod-like mullite particles
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.368-372.744.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of Microstructure on the Wear Resistance of Alumina Dispersed Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-ZrO〈sub〉2〈/sub〉 Ceramics (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 280-283 (Feb. 2007), p. 1069-1074 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of microstructure on the wear resistance of two Al2O3 dispersed in ZrO2 matrix (ADZ) ceramics was investigated, Al2O3 dispersed in commercially co-precipitated 3mol% Y2O3-doped tetragonal zirconia polycrystal (CYADZ) and Al2O3 dispersed in mixed 3mol% Y2O3-doped tetragonal zirconia polycrystal (MYADZ). These materials were used as a pin sliding against a plate of polyurethane rubber (UR) in the presence of aqueous NaOH solution containingSiO2 as the abrasive medium at a sliding speed of 0.15m/s and a normal load of 100N. The results indicated that the CYADZ specimen had uniform microstructure and fine grain size, which accounted for its better abrasive wear-resistance than that of the MYADZ specimen with non-uniform microstructure and largely different grain sizes due to inhomogeneous distribution of Y2O3. The hardness and toughness of two ADZ specimens were close, but strength of the MYADZ specimenwas lower than that of the CYADZ specimen, which indicated the defect was serious in the MYADZspecimen. The CYADZ specimen was characterized by plastic deformation and micro-ploughing, which the MYADZ specimen dominated by micro- cracking and brittle fracture
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.280-283.1069.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Sintering of Vitrified Bond CBN Grinding Tool (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 280-283 (Feb. 2007), p. 1391-1394 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Cubic boron nitride(CBN) is a superhard materials with many advantages and many uses. Vitrified bond CBN grinding tool is a promising abrasive tool of high performance used for high speed, high efficiency, high precision grinding with lower grinding cost and less environment pollution. Sintering of vitrified bond CBN grinding tool was investigated in this paper. The results showed that practical sintering temperature of this tool was much lower than the initial oxidation temperature of CBN particle measured by comprehensive thermal analysis. The upper limit of sintering temperature should be determined by taking account of the thermal analyzing results, heating process of CBN and its change in strength and structure. Within the sintering temperature range of the vitrified bond, relatively higher sintering temperature was beneficial to the strength of bond bridge and the holding strength between bond and CBN abrasive particles. CBN tool sintered at relatively lower temperature tended to fracture through the bond bridge, while the one sintered at higher temperature tended to fracture along the boundary between CBN abrasive grain and vitrified bond
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.280-283.1391.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    Investigation on the Preparation of Vitrified Bond CBN Grinding Tools (2004)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 259-260 (Mar. 2004), p. 33-36 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/47/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.259-260.33.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of Second Sintering on Intragranular Structure and Mechanical Properties of 10vol%Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/3Y-TZP Composites (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 1324-1326 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: To study the effect of second sintering on intragranular structure and mechanical properties of10vol%Al2O3/3Y-TZP composites, the composites were prepared by ball-milling nano-γ-Al2O3 andnano-ZrO2(3mol%Y2O3), pressing unidirectionally, cold-pressing isostatically, then first sintering at1400°C for 2h and second sintering at 1600°C for 5h in air. The composition and microstructure of thecomposites were examined by X-ray diffractometer and scanning electron microscope, transmissionelectron microscope. The results showed that the second sintering changed the microstructure andfracture mode. After second sintering, the structure of fine grains was changed into the mixed one of largegrains and small grains . Many large grains contained small grains, forming intragranular stucture thatcould be produced by the interblending of not only Al2O3 and ZrO2 but also ZrO2 itself. The intergranularfracture after first sintering was changed into transgranular fracture and intergranular fracture after secondsintering . The second sintering led to grinds growing up and intragranular forming, which enhanced thecontribution of the phase transformation toughening. Although the second sintering resulted in abnormalincrease of grain size, the fracture strength and the fracture toughness of the composite were 667 MPa and12.9 MPa⋅m1/2, respectively, due to the intragranular structure and the enhanced phase transformationtoughening
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.336-338.1324.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    A Study on the Grinding Performance of Y-TZP/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 Ceramics (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 1448-1450 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The correlation between machining performance and mechanical properties of Y-TZP/Al2O3ceramics with different mechanical parameters was investigated. The grinding experiments indicated thatthe flexural strength had a definite influence on machining performance of samples. The higher theflexural strength was, the more difficult the sample was to be ground. XRD analysis showed that anincreasing amount of the monoclinic ZrO2 would reduce the flexural strength of the samples. As a result,the grinding force that the samples underwent also decreased
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.336-338.1448.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Analyticity of scattering for the ϕ4 theory (1989)
    Springer
    Communications in mathematical physics 124 (1989), S. 9-21 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract We consider scattering for the equation (□+m 2)ϕ+λϕ3=0 on four-dimensional Minkowski space. Form〉0, one-to-one and onto wave operatorsW ± λ :H→H are known to exist for all λ≧0, whereH denotes the Hilbert space of finite-energy Cauchy data. We prove that the maps (λ,u)↦W ± λ (u) and (λ,u)↦(W ± λ )−1 (u) are continuous from [0, ∞)×H toH, and extend to real-analytic functions from an open neighborhood of {0}×H∪ℝ×{0}⊂ℝ×H to the Hilbert spaceH −1 of Cauchy data with Poincaré-invariant norm. Form=0, wave operatorsW ± λ are known to exist as diffeomorphisms ofH for all λ≧0, where hereH denotes the Hilbert space of finite Einstein energy Cauchy data. In this case we prove that the maps (λ,u)↦(W ± λ ) (u) and (λ,u)↦(W ± λ )−1 (u) extend to real-analytic functions from a neighborhood of [0, ∞)×H⊂ℝ×H toH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01218466
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