Transverse sections of multifilamentary Nb3Sn superconductor wires in TEM

1978 ◽  
Vol 36 (1) ◽  
pp. 148-149
Author(s):  
Edward F. Koch
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Carrying Capacity ◽  
Flux Pinning ◽  
Diffusion Method ◽  
Solid State Diffusion ◽  
Superconducting Wires ◽  
Hexagonal Shape ◽  
Heat Treated ◽  
State Diffusion

New devices using fine multifilament superconducting wires are becoming more important, since these wires now have better thermal stability, lower losses and better current carrying capacity. The multifilament Nb3Sn superconductor wires reviewed in this report were made by the solid state diffusion method developed by Kaufman and Pickett. In this process, a niobium rod in a bronze jacket is extruded into an hexagonal shape, this rod is then cut into lengths, which are packed together in a bronze jacted and extruded again. This process is continued until the total reduction ratio for the niobium is a billion to one. At this point the wires are still ductile and can be fabricated into their final shape. The Nb2-bronze composite is then heat treated, and the tin from the bronze diffuses into the Nb, forming Nb3Sn. This heat treatment is important, since it controls both the amount of Nb3Sn formed and the grain size, which affects flux-pinning.

Luminescence and defect studies of Ce3+ doped CaS phosphor synthesized via solid state diffusion method

2006 ◽  
Vol 131 (1-3) ◽  
pp. 195-199 ◽  
Author(s):  
Vijay Singh ◽  
T.K. Gundu Rao ◽  
Jun-Jie Zhu ◽  
Manoj Tiwari
Keyword(s):  
Solid State ◽  
Diffusion Method ◽  
Solid State Diffusion ◽  
State Diffusion

Ternary Phase Formation in 95Pb-5Sn Flip-Chip Solder Bonds

1993 ◽  
Vol 323 ◽  
Author(s):  
Alan J. Mockler ◽  
Peter J. Goodhew ◽  
Elizabeth A. Logan
Keyword(s):  
Heat Treatment ◽  
Solid State ◽  
Ternary Phase ◽  
Flip Chip ◽  
Phase Distribution ◽  
Intermetallic Phases ◽  
Ternary Diagram ◽  
Solid State Diffusion ◽  
Analysis Techniques ◽  
State Diffusion

AbstractThe microstructure of 95Pb-5Sn flip-chip solder bonds deposited on Cr/Cu/Au metallisation pads has been studied using both light and electron analysis techniques. The presence of Sn-Cu- Au ternary intermetallic phases was detected within the Pb-rich matrix at significant distances from the originally deposited interface. The distribution of the phases present after the solder has undergone a reflow heat treatment can be interpreted using recent equilibrium ternary diagram data. An investigation was also made into the effects of various non-reflow heat treatments at carefully chosen temperatures, to qualitatively evaluate the extent of solid state diffusion and the resultant phase distribution.

Solid-State Diffusion Formation of Nanocrystalline Nb3Sn Layers at Two-Staged Annealing of Multifilamentary Nb/Cu-Sn Wires

2012 ◽  
Vol 16 ◽  
pp. 69-75 ◽  
Author(s):  
E.N. Popova ◽  
I.L. Deryagina ◽  
E.P. Romanov ◽  
E.A. Dergunova ◽  
A.E. Vorobyova ◽  
...  
Keyword(s):  
Diffusion Annealing ◽  
Solid State Diffusion ◽  
Superconducting Layer ◽  
Superconducting Wires ◽  
Second Stage ◽  
State Diffusion ◽  
Columnar Grains ◽  
Average Size ◽  
Bronze Matrix ◽  
Active Formation

The structure of Nb3Sn-based, bronze-processed Ti-doped multifilamentary superconducting wires has been studied by TEM and SEM after the first (5750C,100 h) and the second (6500C,100 h) stage of the diffusion annealing. The Nb3Sn layers formation in all the composites proceeds by one and the same mechanism and starts with nucleation of particles and very fine grains of this phase in Nb filaments where Sn diffuses from the bronze matrix. Ti, inserted both in the bronze matrix, or Nb filaments, diffuses into the growing superconducting layer and promotes its more active formation. At the first stage of annealing (5750C, 100 h) Nb3Sn grains have an average size of 40 nm, and at the second stage (6500C, 100 h) they increase by a factor of 1.5 and the grain size distribution gets wider. After the two-stage annealing the amount of the residual niobium is small, and some Nb filaments, especially in doped composites, almost completely transform into Nb3Sn. In the Nb3Sn layers of a zone of columnar grains is adjacent to the residual Nb.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

GaAs shallow homojunction solar cells fabricated on thin epitaxial films by a simple Zn solid state diffusion method

1986 ◽  
Vol 14 (1) ◽  
pp. 29-49 ◽  
Author(s):  
M. Garozzo ◽  
A. Parretta ◽  
G. Maletta ◽  
V. Adoncecchi ◽  
M. Gentili
Keyword(s):  
Solar Cells ◽  
Solid State ◽  
Epitaxial Films ◽  
Diffusion Method ◽  
Solid State Diffusion ◽  
State Diffusion

Photoluminescence and Thermoluminescence Properties of Eu2+ and Ce3+ Activated BaAlSi5O2N7 Phosphors

2015 ◽  
Vol 361 ◽  
pp. 177-193 ◽  
Author(s):  
S.A. Fartode ◽  
Vijay Singh ◽  
S.J. Dhoble
Keyword(s):  
Glow Curve ◽  
Optical Spectrum ◽  
Broad Band ◽  
Diffusion Method ◽  
Solid State Diffusion ◽  
Strong Emission ◽  
Light Emitting ◽  
State Diffusion ◽  
Higher Temperature ◽  
White Light Emitting Diodes

Ce3+ and Eu2+ activated BaAlSi5O2N7 phosphors have been prepared by the modified three step solid state diffusion method. Prepared phosphors are characterized by XRD, SEM, photoluminescence and thermoluminescence techniques. Upon excitation at 234nm, Ce3+ activated BaAlSi5O2N7 phosphor shows strong emission at 360nm. Upon excitation at 348nm, Eu2+ activated BaAlSi5O2N7 phosphor shows strong emission at 469nm in the blue region of the optical spectrum. After quenching at higher temperature and upon excitation at 363nm, BaAlSi5O2N7:Eu2+ phosphor shows broad band at 516nm in the green region of the optical spectrum. The trap parameters are studied using glow curve deconvolution. It was found that the obtained samples may be suitable for near UV excited white light emitting diodes.

Boron-doped Nanodiamond Powder Prepared by Solid-state Diffusion Method

2015 ◽  
Vol 44 (5) ◽  
pp. 627-629 ◽  
Author(s):  
Takeshi Kondo ◽  
Narumi Okada ◽  
Yuki Yamaguchi ◽  
Junichi Urai ◽  
Tatsuo Aikawa ◽  
...  
Keyword(s):  
Solid State ◽  
Diffusion Method ◽  
Solid State Diffusion ◽  
Boron Doped ◽  
State Diffusion

Thermal Stability of Cu and Cu2O Nanoparticles in a Polyimide Film

2008 ◽  
Vol 8 (9) ◽  
pp. 4822-4825 ◽  
Author(s):  
Jae-Youn Choi ◽  
Wenguo Dong ◽  
Dong Joo Choi ◽  
Chong S. Yoon ◽  
Young-Ho Kim
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Polyimide Film ◽  
Cu Nanoparticles ◽  
Transmission Electron ◽  
Heat Treated ◽  
Cu Film ◽  
Vis Spectroscopy ◽  
Cu2o Nanoparticles ◽  
Thermal Stability Of

Nanoparticles of Cu or Cu oxide dispersed in a polyimide (PI) film were fabricated by reaction of polyamic acid with a thin Cu film during imidization. In this paper, the thermal stability of the Cu or Cu oxide nanoparticles was investigated under various atmospheres. The PI/nanoparticle composites were heat-treated at 140 °C and 250 °C in air, N2, Ar, and 5% H2 atmospheres. Nanoparticles in the PI film were characterized by UV-VIS spectroscopy and transmission electron microscopy. The optical absorption peaks originating from Cu or Cu2O nanoparticles were changed by heat-treatment in different atmospheres. When Cu nanoparticles were oxidized by heat-treatment in air, the surface plasmon resonance (SPR) peak originating from the Cu nanoparticles disappeared. The quantum confined absorption peak of Cu2O was not affected by heat-treatment in N2 or Ar. Cu2O nanoparticles were reduced by heat-treatment at 250 °C in 5% H2 atmosphere and a new SPR peak appeared. Our results show that Cu nanoparticles are easily oxidized and highly dense Cu nanoparticles can be formed by reducing Cu2O nanoparticles.

Microstructure of SiC / TiAl Interface Formed by Solid-State Diffusion Bonding

2005 ◽  
Vol 502 ◽  
pp. 461-466
Author(s):  
Masakatsu Maeda ◽  
Kazuyuki Tenyama ◽  
Toshiya Shibayanagi ◽  
Masaaki Naka
Keyword(s):  
Solid State ◽  
Diffusion Bonding ◽  
Titanium Aluminide ◽  
Chemical Potential ◽  
Interfacial Microstructure ◽  
Solid State Diffusion ◽  
Reaction Products ◽  
Phase Sequence ◽  
Heat Treated ◽  
State Diffusion

The microstructure of the solid-state diffusion bonded interfaces of silicon carbide (SiC) and titanium aluminide (TiAl) were investigated. A 100-µm-thick Ti-48at%Al foil was inserted between two SiC specimens and then heat-treated in vacuum. The interfacial microstructure has been analyzed by scanning electron microscopy, electron probe microanalysis and X-ray diffractometry. Four layers of reaction products are formed at the interface by diffusion bonding: a layer of TiC adjacent to SiC followed by a diphase layer of TiC+Ti2AlC, a layer of Ti5Si3CX containing Ti2AlC particles and a layer of TiAl2. However, the TiAl2 layer is formed during cooling. The actual phase sequence at the bonding temperatures of 1573 K and 1673 K are described as SiC/TiC/(TiC+ Ti2AlC)/(Ti5Si3CX+Ti2AlC)/Ti1-XAl1+X/TiAl and SiC/TiC/(TiC+Ti2AlC)/(Ti5Si3CX+Ti2AlC)/Ti5Al11 /Ti1-XAl1+X/TiAl, respectively. The phase sequences are successfully expressed on the basis of the Ti-Al-Si-C quaternary chemical potential diagram.

Sign in / Sign up

Export Citation Format

Share Document