High-pressure apparatus (HPA) of recessed anvil and cube types and schemes of the load distribution in the HPA. The arrangement shown is suitable for treatment, sintering, or synthesis of SC materials.
Unit cell parameters , , : of Y123 initial powder and Y123 ceramics sintered under 2 and vs. treatment temperature ; of Y123 phase of MT–YBCO before and after treatment under 2 and vs. treatment temperature .
Critical current density in zero magnetic field at : of Y123 powder and Y123 ceramics sintered under 2 and , of MT–YBCO before and after HP–HT treatment under in the plane and in the perpendicular direction .
Critical current density vs. magnetic field ( plane of Y123) at for MT–YBCO–Ag before and after HP–HT treatment.
Structure of melt-textured ceramics before and after HP–HT treatment: starting MT–YBCO–Ag MT–(Nd,Y)BCO , and MT–YBCO–Ag treated at , for , MT–(Nd,Y)BCO treated at , for .
TEM image showing a wide region with the high density of dislocations lying on the (001) plane of Y123 in MT–YBCO (treated at , , ).
Critical current density vs. magnetic field , T at obtained using VSM for the cases that the external magnetic field was perpendicular and parallel to the plane of Y123 for: MT–YBCO oxygenated at a pressure of ; MT–YBCO untwined by HP–HT treatment under .
TEM images show the low twin density, perfect dislocations stepped along directions and small faulted loops corresponding to intercalating in the matrix of treated at MT–YBCO; , TEM image of the structure of MT–YBCO oxygenated under shows a high twin and stacking fault density around Y211 inclusions .
Trapped-field map for the MT–YBCO ring ( , ) joined by Tm123 powder. Regular shape of the truncated cone indicates that the trapped magnetic field is homogeneously distributed throughout the ring and that the critical current density in the seam is approximately the same as in the joined material . Magnetooptical image of the same joined ring obtained at . The brighter is the local area of the image, the larger is the local magnetic induction . Critical current density vs. the magnetic field of the same single-domain ring before cutting (curve 1), after cutting and soldering at (curve 2) and after cutting, soldering, and oxygenation (curve 3). In the upper right corner the initial magnetization loops used for the calculation are given . Microstructure of the soldered seam in the ring in: polarized light, and obtained by SEM of the same place in different regimes: SEI and COMPO .
X-ray patterns and critical current densities vs. magnetic field variation at different temperatures for samples synthesized at for from Mg and B (without additions) at 950, 900, and , respectively ; backscattering electron image obtained by SEM of the sample synthesized from Mg and B at and for ; energy-dispersive spectra of the sample shown in Fig 10d : gray-colored spectrum is the spectrum of the “black” inclusions, and the white-colored spectrum is the spectrum of the “matrix” phase of the sample .
X-ray patterns, dependences of on magnetic fields , and structure obtained by SEM in backscattering electron image of the HPS– with additions of , Ti, and Zr. (Regimes of synthesis and amount of additions are given in the pictures.) The vs. amount of “black” inclusions, , for HPS– samples without additions and with additions of Ta and Ti [ was calculated as a ratio of the area that is occupied by “black” inclusions in the image of the structure obtained at magnification to the total area of the image obtained by SEM in the backscattering electron regime] .
Generalized dependences of on for without and with additions of Ta, Ti, Zr, and nano- at different temperatures , K: 10 , 20 , 30 .
ion maps of the distribution of mass , mass 11 B, mass 49 , and mass 24 in high-pressure-synthesized material with a Ti addition.
Bright-field TEM image of a particle from the powdered sample of the high-pressure-synthesized material with Ti addition. Electron diffraction pattern contrast inverted from the Ti-rich particle shown in .
Microhardness , fracture toughness , Young’s modulus , and density before and after treatment of MT–YBCO (at , for ) and (at , , ).
Table comparing enthalpies of formation values for a range of common Ti compounds. 23
Article metrics loading...
Full text loading...