Radiation‐enhanced diffusion growth of Nb3Sn monofilaments: Grain‐size effects on critical‐current density

1980 ◽  
Vol 36 (6) ◽  
pp. 474-476 ◽  
Author(s):  
C. L. Snead ◽  
M. Suenaga
Keyword(s):  
Grain Size ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Size Effects ◽  
Diffusion Growth ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Grain Size Effects

Study on the High Speed Jet-Electrode Position Ni-P Alloy

2013 ◽  
Vol 567 ◽  
pp. 39-44
Author(s):  
Ying Wang ◽  
Min Kang ◽  
Yong Yang ◽  
Xiu Qing Fu
Keyword(s):  
Grain Size ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
High Speed ◽  
Electrode Position ◽  
Stirring Intensity

The high speed jet-electrodepositing equipment was used to prepare Ni-P alloy in substrate of 45 steel. The influences of current density on depositing rate, hardness of deposit and microstructure of Ni-P alloy were studied, and the comparation with that of conventional electroplating were studied. The results show that with the increase of stirring intensity of the electrolyte, the thickness of diffused layer decreases, the critical current density increases, and then the depositing rates increase to 69.82/min. A linear increasing of the depositing rate with the increase of current density is observed, and it refines grain size obviously. Deposit hardness up to 679HV.

scholarly journals Effect of grain size and doping level of sic on the superconductivity and critical current density in MgB/sub 2/ superconductor

2003 ◽  
Vol 13 (2) ◽  
pp. 3273-3276 ◽  
Author(s):  
S. Soltanian ◽  
Xiaolin Wang ◽  
J. Horvat ◽  
Mengjun Qin ◽  
Huakun Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Doping Level

Crystallization of A15 Nb3Ge from the amorphous state

1990 ◽  
Vol 5 (3) ◽  
pp. 478-483
Author(s):  
Marcin Wardak ◽  
Mireille Treuil Clapp
Keyword(s):  
Grain Size ◽  
Critical Current Density ◽  
Critical Current ◽  
Grain Growth ◽  
Current Density ◽  
Amorphous Material ◽  
Amorphous State ◽  
Average Grain Size ◽  
Melt Spun ◽  
Melt Spun Ribbons

The critical current density Jc of superconductors is strongly dependent on microstructure. The microstructure and crystallization of amorphous Nb75Ge24.5B0.5 melt spun ribbons were studied as a function of 24-h anneals between 680 and 860 °C. Metastable A15 was formed with a composition close to that of the starting amorphous material. As the temperature increased from 680 to 720°C, crystallization remained nonuniform and the average grain size decreased from 130 nm to 60 nm. Between 740 and 800°C crystallization was uniform and the average grain size was constant at 30 nm. Above 820°C grain growth occurred. In order to have high Jc's a uniformly crystallized small-grained material is desirable.

scholarly journals Influence of Amorphous Boron Grain Size, High Isostatic Pressure, Annealing Temperature, and Filling Density of Unreacted Material on Structure, Critical Parameters, N-Value, and Engineering Critical Current Density in Mgb2 Wires

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3600
Author(s):  
Daniel Gajda ◽  
Andrzej J. Zaleski ◽  
Andrzej Morawski ◽  
Małgorzata Małecka ◽  
Mustafa Akdoğan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Liquid State ◽  
Critical Parameters ◽  
Heterogeneous Structure ◽  
Synthesis Reaction ◽  
N Value

Our results show that a lower density of unreacted Mg + B material during an Mg solid-state synthesis reaction leads to a significant reduction in the quantity of the superconducting phase and lowers the homogeneity of the superconducting material. It also significantly reduces the irreversible magnetic field (Birr), critical temperature (Tc), upper magnetic field (Bc2), engineered critical current density (Jec), and n-value, despite high isostatic pressure (HIP) treatment and the use of nanoboron in the sample. Our measurements show that samples with large boron grains with an 8% higher density of unreacted Mg + B material allow better critical parameters to be achieved. Studies have shown that the density of unreacted material has little effect on Birr, Tc, Bc2, Jec, and the n-value for an Mg liquid-state synthesis reaction. The results show that the critical parameters during an Mg liquid-state synthesis reaction depend mainly on grain size. Nanoboron grains allow for the highest Birr, Tc, Bc2, Jec, and n-values. Scanning electron microscopy (SEM) images taken from the longitudinal sections of the wires show that the samples annealed under low isostatic pressure have a highly heterogeneous structure. High isostatic pressure heat treatment greatly improves the homogeneity of MgB2.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

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