High thermal stability of core–shell structures dominated by negative interface energy

2017 ◽  
Vol 19 (13) ◽  
pp. 9253-9260 ◽  
Author(s):  
Yong-Fu Zhu ◽  
Ning Zhao ◽  
Bo Jin ◽  
Ming Zhao ◽  
Qing Jiang

Superheating of the low-Tm(∞)-core is induced by the negative interface energy, improving thermal expansion, atomic diffusion and heat capacity accordingly.

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2583
Author(s):  
Pengpeng Qu ◽  
Feifei Li ◽  
Sajjad Ur Rehman ◽  
Lei He ◽  
Xiaoqiang Yu ◽  
...  

The grain boundary diffusion process (GBDP) has become an important technique in improving the coercivity and thermal stability of Dy-free sintered Nd-Fe-B magnets. The influence of Dy70Al10Ga20 and (Pr75Dy25)70Al10Ga20 alloys by the GBDP on sintered Nd-Fe-B magnets are investigated in this paper. After diffusing Dy70Al10Ga20 and (Pr75Dy25)70Al10Ga20 alloys, the coercivity (Hcj) of the magnets increased from 13.58 kOe to 20.10 kOe and 18.11 kOe, respectively. Meanwhile, the remanence of the magnets decreased slightly. The thermal stability of the diffused magnets was improved by the GBDP. The microstructure shows continuous Rare-earth-rich (RE-rich) grain boundary phases and (Dy, Pr/Nd)2Fe14B core-shell structures which contribute to improving the coercivity. Moreover, the Dy concentration on the surface of the (Pr75Dy25)70Al10Ga20 diffused magnets decreased with the Pr substitution for the Dy element. The openness of the recoil loops for the (Pr75Dy25)70Al10Ga20 diffused magnets is smaller than that of the original magnets and Dy70Al10Ga20 diffused magnets. The results show that the (Pr75Dy25)70Al10Ga20 alloys can effectively optimize the microstructure and improve the magnetic properties and thermal stability of the sintered Nd-Fe-B magnets.


2010 ◽  
Vol 59 (4) ◽  
pp. 733-740 ◽  
Author(s):  
M. P. Yutkin ◽  
M. S. Zavakhina ◽  
D. G. Samsonenko ◽  
D. N. Dybtsev ◽  
V. P. Fedin

Author(s):  
F.F. do Carmo ◽  
J.P.C. do Nascimento ◽  
J.E.V. de Morais ◽  
V.C. Martins ◽  
J.C. Sales ◽  
...  

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3393 ◽  
Author(s):  
Jin Cheng ◽  
Yu Zhou ◽  
Xiaoping Zou

Fiber Fabry–Perot cavity sensing probes with high thermal stability for dynamic signal detection which are based on a new method of structure compensation by a proposed thermal expansion model, are presented here. The model reveals that the change of static cavity length with temperature only depends on the thermal expansion coefficient of the materials and the structure parameters. So, fiber Fabry–Perot cavity sensing probes with inherent temperature insensitivity can be obtained by structure compensation. To verify the method, detailed experiments were carried out. The experimental results reveal that the static cavity length of the fiber Fabry–Perot cavity sensing probe with structure compensation hardly changes in the temperature range of −20 to 60 °C and that the method is highly reproducible. Such a method provides a simple approach that allows the as-fabricated fiber Fabry–Perot cavity acoustic sensor to be used for practical applications, exhibiting the great advantages of its simple architecture and high reliability.


2006 ◽  
Vol 510-511 ◽  
pp. 434-437 ◽  
Author(s):  
Yu Liang Liu ◽  
Tian Ying Xiong ◽  
Ke Yang

Surface Nanocrystallization(SNC) is a new method of fabricating nanostructured materials while thermal stability is an important problem for the application of nanostructured materials. A nanostructured layer was fabricated on the surface of 40Cr steel by Supersonic Particles Bombarding method, and the variation of microstructure and microhardness of nanostructured layer was studied. Nanostructured surface layer showed high thermal stability.


2021 ◽  
pp. 93-98
Author(s):  
Evgenii Erofeev ◽  
Egor Polyntsev ◽  
Sergei Ishutkin

Electrophysical characteristics and their thermal stability of thin-film resistors based on tantalum nitride (TaN) obtained by reactive magnetron sputtering were investigated. The optimal modes of the magnetron sputtering process are determined, ensuring the Ta2N phase film composition with the value of the specific electrical resistance of 250 μm cm and high thermal stability of the parameters. On the basis of the investigations carried out, thin-film matching resistors were manufactured for use as part of an electro-optical InP-based MZ modulator


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