scholarly journals Fabrication of ZnO Ceramics with Defects by Spark Plasma Sintering Method and Investigations of Their Photoelectrochemical Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2506
Author(s):  
Liren Zheng ◽  
Mu Liu ◽  
Haipeng Zhang ◽  
Zhaoke Zheng ◽  
Zeyan Wang ◽  
...  

ZnO, as an important semiconductor material, has attracted much attention due to its excellent physical properties, which can be widely used in many fields. Notably, the defects concentration and type greatly affect the intrinsic properties of ZnO. Thus, controllable adjustment of ZnO defects is particularly important for studying its photoelectric properties. In this work, we fabricated ZnO ceramics (ZnO(C)) with different defects through spark plasma sintering (SPS) process by varying sintering temperature and using reduction environment. The experimental results indicate that the changes of color and light absorption in as-prepared ZnO originate from the different kinds of defects, i.e., oxygen vacancies (VO), interstitial zinc (Zni), and Zinc vacancies (VZn). Moreover, with the increase in calcination temperature, the concentration of oxygen defects and interstitial zinc defects in the ceramics increases gradually, and the conductivity of the ceramics is also improved. However, too many defects are harmful to the photoelectrochemical properties of the ceramics, and the appropriate oxygen defects can improve the utilization of visible light.

2021 ◽  
Vol 405 ◽  
pp. 126511
Author(s):  
Weisheng Liu ◽  
Xuanru Ren ◽  
Hongao Chu ◽  
Menglin Zhang ◽  
Qingqing Yang ◽  
...  

2007 ◽  
pp. 3201-3206
Author(s):  
Hisashi Sato ◽  
Seiichiro Umaoka ◽  
Yoshimi Watanabe ◽  
Ick Soo Kim ◽  
Masakazu Kawahara ◽  
...  

2020 ◽  
Vol 40 (15) ◽  
pp. 5529-5534 ◽  
Author(s):  
Haoxian Chen ◽  
Qianying Sun ◽  
Tian Tian ◽  
Liaoying Zheng ◽  
Maud Barré ◽  
...  

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1355
Author(s):  
Zhiyong Xue ◽  
Xiuzhu Han ◽  
Wenbo Luo ◽  
Zhiyong Zhou ◽  
Zhizhong Cheng ◽  
...  

The synergic strengthening of multiple phases is an essential way to achieve high-performance Mg alloys. Herein, Mg-Gd-Zn alloy containing four phases was prepared by rapid solidification (RS) ribbons and spark plasma sintering (SPS). The microstructure of the alloy consisted of α-Mg, nanosized β1 phase particles, lamellar long period stacking ordered (LPSO) phase, and β′ phase precipitates. The microstructural evolution was also investigated. The results show that the metastable β1 phase was formed in the as-cast solidification through rapid solidification, because both Zn atoms and the short holding-time at molten liquid facilitated the formation of the β1 phase. The β1 phase grew from 35.6 to 154 nm during the sintering process. Meanwhile, the fine lamellar LPSO phase was simultaneously formed after the Zn-Gd clusters were generated from the supersaturated solid solution, and the width of the LPSO phase was only in the range of 2–30 nm. The third strengthening phase, the metastable β′ phase, was obtained by aging treatment. The results of hardness testing implied that the hardness of the alloy containing the aforementioned three nanosized strengthening phases significantly improved about 47% to 126 HV compared with that of the as-cast ingot.


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