Fabrication of CuO and Cu2O Nanoparticles in a Thick Polyimide Film by Post Heat Treatment in a Controlled-Atmosphere

2011 ◽  
Vol 11 (1) ◽  
pp. 796-800 ◽  
Author(s):  
Junro Yoon ◽  
Dong Joo Choi ◽  
Young-Ho Kim
2008 ◽  
Vol 8 (9) ◽  
pp. 4822-4825 ◽  
Author(s):  
Jae-Youn Choi ◽  
Wenguo Dong ◽  
Dong Joo Choi ◽  
Chong S. Yoon ◽  
Young-Ho Kim

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.


2021 ◽  
Vol 64 ◽  
pp. 620-632
Author(s):  
Alexander Malikov ◽  
Anatoly Orishich ◽  
Igor Vitoshkin ◽  
Evgeniy Karpov ◽  
Alexei Ancharov

2012 ◽  
Vol 536 ◽  
pp. S200-S203 ◽  
Author(s):  
H.S. Kim ◽  
W.Y. Kim ◽  
K.H. Song

2007 ◽  
Vol 546-549 ◽  
pp. 2031-2034
Author(s):  
Y.F. Wu ◽  
G. Yan ◽  
J.S. Li ◽  
Y. Feng ◽  
Shao Kai Chen ◽  
...  

The powder-in-tube MgB2 wires were prepared by high energy milling of Mg and B powder. The powder was not mechanically alloyed for 2h short milling time. However, the MgB2 grains in wires were very small (20~100nm) and resemble the dimple after post-heat treatment. The clear evidence for transcrystlline fracture was observed. It indicated that the grain connection was greatly improved and the fluxing pinning was significantly enhanced. Another point to view was no intermediate annealing during the whole rolling process. The influence of the post-heat treatment on the transport current density was studied. Despite the lower Tc of about 35K, the transport current density reached to 3×104A/cm2 at 15K and 3.5T for wires sintered at 700°C.


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