Library

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
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 3379-3381 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Features as fine as 4 μm with high aspect ratio were produced from ceria-zirconia ceramic using a thick plasma-etched polyimide layer as a micromold.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 6382-6388 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Rapid thermal processing has been utilized to sinter and anneal phase-pure and CuO-rich YBa2Cu3O7 fibers and woven fibers formed by melt spinning a powder/polymer composite. The optimum temperature for sintering the powders varies for the stoichiometric (1025 °C) and 5% CuO-rich fibers (1000 °C), but in both cases the temperature window is extremely narrow (±25 °C). Typical processing consists of a rapid heating (250 °C/s) of the fibers to the sintering temperature in 1 atm of pure oxygen, holding at temperature for 1 s and cooling over a period of 2–3 min. The resulting fibers are orthorhombic YBa2Cu3O7 with large Meissner and shielding fractions, have zero resistance up to 92 K, critical-current densities in zero applied field to 1100 A/cm2 at 76 K, and show clean grain boundaries by transmission electron microscopy. Despite the short processing times, microstructural analysis shows considerable grain growth and evidence of metastable congruent melting of oxygen-rich YBa2Cu3O7.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 28 (1987), S. 1-16 
    ISSN: 1573-4889
    Keywords: Silicon oxidation ; tracer ; double oxidation ; oxygen diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This work focuses on the thermal oxidation of silicon near 1273 K using the double-tracer oxidation method. The results confirm that oxidation occurs by the transport of electrically neutral non-network oxygen through the interstitial space of the vitreous silica (ν-SiO2) scale. Simultaneously, self- (or isotopic-) diffusion occurs in the network, resulting in characteristic isotopic fraction distributions near the gas-scale interface. The self-diffusion coefficients calculated from these profiles agree with those reported for tracer diffusion in ν-SiO2, and the diffusion coefficient calculated from the scale growth is consistent with reported O2 permeation data. An important parameter that describes the double-oxidation behavior is the ratio of the value of Δ/√(D nt′),where Δ is the scale thickness grown during the second oxidation, Dn is the network self-diffusion coefficient for oxygen, and t′ is the time of the second oxidation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 27 (1987), S. 143-155 
    ISSN: 1573-4889
    Keywords: double-oxidation ; O-18 ; tracer concentration profile ; diffusion model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two methods are presented for the analysis of oxygen tracer isotope “double oxidation” experiments. Mass balance criteria are presented for inferring oxide growth mechanisms from the oxygen isotope profile. For the case of inward growing scales, a diffusion model is presented which describes the tracer distribution as a function of lattice and grain boundary diffusivities, grain size and the parabolic growth rate.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 33 (1998), S. 2795-2803 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The research presented herein has focused on debinding of an ethylene copolymer from a SiC based moulded ceramic green body within an inert atmosphere. Upon heating, the pure polymer undergoes a two-stage thermal degradation process. In the first stage, acetic acid is the only degradation product formed. The effect of the introduction of high surface area powder on the chemistry and kinetics of this first stage reaction was examined. The effluents were captured and analysed in a gas chromatograph/mass spectrometer. The product of the reaction was not altered by introduction of the ceramic powder. However, the kinetics of the reaction were altered. The kinetics of the reaction were determined with the use of thermogravi metric analysis (TGA). The mechanism of mass transport during binder removal was determined by monitoring dimensional changes during binder removal. It was found that one unit volume of shrinkage corresponded with one unit volume of binder removed, indicating that no porosity developed. The escaping acetic acid effluents must diffuse through the liquid polymer filled pores to escape. Bloating was observed in certain conditions and was attributed to the concentration of acetic acid exceeding a critical value, resulting in bubbling.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 34 (1999), S. 3281-3290 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper focuses on determining the criteria for defect formation during the early stages of thermal binder removal within an ethylene vinyl acetate (EVA) polymer filled with submicron SiC ceramic powder. The only product of the early stage thermal degradation reaction of EVA within an inert atmosphere is acetic acid. This single component and well characterized organic reaction product has allowed the defect forming criteria to be definitively examined. It will be shown that bloating occurs in the early stages of binder removal as a result of pressure build-up in the specimen resulting from acetic acid formed from the thermal elimination reaction of EVA. The first part of this paper examines defect formation occurring in the pure polymer within a hot-stage optical microscope. Bubble formation is observed in the pure polymer. Next, bloating occurring in the molded system is examined. The affect of mineral oil on bloating is also discussed as well as the effect that molding pressure has on bloating. It was found that molding pressure effects defect formation. Finally, this paper presents binder removal maps that were developed for specimens up to 8 mm thick. These bloating maps indicate the existence of two primary bloating regimes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 33 (1998), S. 2805-2815 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Significant dimensional changes involving linear expansion and shrinkage of 6% occur during heating of a thermoplastic SiC/ethylene vinyl acetate (EVA) mixture. Thermal expansion occurs before weight loss begins, and can be quantitatively explained in terms of the thermal expansion behaviour of the constituents and the crystallization or melting of the semicrystalline polymer. Irreversible anisotropic displacements occur during the first heating cycle due to relaxation of moulding strains. These can be reduced by annealing for periods comparable to the viscoelastic relaxation of the ceramic/polymer system. Shrinkage occurs during the early stages of degradation of EVA. This shrinkage is quantitatively accounted for with volume losses resulting from removal of the EVA. Shrinkage continues as weight loss proceeds and stops only at the point the ceramic particles contact one another. Total displacement behaviour is the sum of the shrinkage from weight loss plus the expansion from thermal expansion of the individual components, and can be quantitatively predicted for simple or multi-step heating schedules.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 33 (1998), S. 4551-4560 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Suspensions of alumina powders in low-viscosity acrylate monomers were produced and their curing behaviour characterized. Although these suspensions contain 50 vol % Al2O3 particles, the viscosity is between 200 and 300 mPas. These suspensions were rendered ultraviolet-curable by the addition of photoinitiators sensitive to ultraviolet radiation. Photopolymerization kinetics were characterized via differential photo-calorimetry. Photopolymerization rates and monomer conversions were unaffected by the presence of the alumina filler. Increasing the average functionality of the monomer mixture tended to increase slightly the photopolymerization rate and decrease the final conversion. Higher concentrations of photoinitiator increased both the rate of photopholymerization and the final conversion. The presence of oxygen was shown severely to restrict polymerization in these filled systems as well. © 1998 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 35 (2000), S. 3365-3371 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Preferred orientation was measured in Si3N4/BN fibrous monolithic ceramics using x-ray diffraction. The materials were manufactured by co-extrusion of polymer binder/ceramic blends which were subsequently pyrolized and then hot-pressed to produced a fully dense ceramic composite. A very strong modified wire texture was present in the BN with the basal planes aligned parallel to the axis of extrusion due to shear-induced reorientation of the platelet-shaped BN particles during co-extrusion. Texture was also observed in the Si3N4 and was attributed to a combination of co-extrusion and hot-pressing. After hot pressing, the basal planes of the rod-shaped β-Si3N4 were observed to be preferentially aligned perpendicular to the extrusion direction. Measurements prior to hot-pressing revealed that a small amount (≈5%) of β-Si3N4 was present in the α-Si3N4 starting powder. Although texturing of the predominant α-Si3N4 did not occur during co-extrusion, significant texturing of the β-Si3N4 was observed. During subsequent hot-pressing, the pre-existing textured β-Si3N4 particles appeared to act as seeds for transformation and preferred growth of rod-shaped β grains parallel to the axis of extrusion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...