Phase evolution and densification behavior of PBN ceramics

The effect of LnAlO3 (Ln = Nd, Sm) additives on the densification, phase evolution, microstructure and dielectric properties of BaO-Nd2O3-5TiO2 (BNT5) ceramics was investigated. The LnAlO3 (Ln = Nd, Sm) had greatly influence on the densification behavior of the BNT5 ceramics and the grain sizes of BNT5 ceramics could be effectively refined by LnAlO3 additive. The microstructure of BNT5 ceramics was transformed from quasi-rectangular grain to columnar grain while the content of LnAlO3 was increasing. The dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) were reduced with the increase of LnAlO3 content, whereas the Q×f values showed a non-linear behaviour with LnAlO3 content increasing. The BNT5 ceramics doped with 12.5 wt% SmAlO3, sintered at 1320°C for 4 h, had the excellent dielectric properties of εr = 62.78, Q×f = 11108 GHz and τf = -1.55 ppm/°.

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Phase evolution and densification behavior of MIM418 superalloy utilizing master alloy approach

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2018.08.193 ◽

2019 ◽

Vol 771 ◽

pp. 33-41 ◽

Cited By ~ 3

Author(s):

Xiaowei Chen ◽

Lin Zhang ◽

Ye Liu ◽

Xiaoyong Gao ◽

Dan Li ◽

...

Keyword(s):

Master Alloy ◽

Phase Evolution ◽

Densification Behavior

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Densification behavior and phase evolution of Mg-doped sialon

Journal of Asian Ceramic Societies ◽

10.1016/j.jascer.2017.10.001 ◽

2017 ◽

Vol 5 (4) ◽

pp. 452-459

Author(s):

Zhangfu Yang ◽

Liqiang Zhang ◽

Qinglin Shang ◽

Jingjing Yuan ◽

Yin Liu ◽

...

Keyword(s):

Phase Evolution ◽

Densification Behavior ◽

Mg Doped

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Chemical Availability of Bromide Dictates CsPbBr3 Nanocrystal Growth

10.26434/chemrxiv.8081504 ◽

2019 ◽

Author(s):

Je-Ruei Wen ◽

Benjamin Roman ◽

Freddy Rodriguez Ortiz ◽

Noel Mireles Villegas ◽

Nicholas Porcellino ◽

...

Keyword(s):

Reaction Time ◽

Growth Mechanism ◽

Chemical Control ◽

Critical Role ◽

Phase Evolution ◽

Detailed Understanding ◽

Semiconductor Nanocrystal ◽

Nanocrystal Growth ◽

Chemical Availability

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>

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