sintering method
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2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenhong Han ◽  
Guilin Wei ◽  
Yi Liu ◽  
Xirui Lu ◽  
Shunzhang Chen ◽  
...  

Abstract A new glass solidification process aims at radioactive iodine waste was explored in order to reduce the possible harm to environment. Samples with different iodine content in silver-coated silica gel were pretreated by hydration device at 300 °C and then sintered at relatively low temperatures (500, 550 and 600 °C). XRD results show that AgI is mainly chemically fixed in the glass network with some AgI particles being physically wrapped by the glass. Moreover, as the sintering temperature reached to 550 °C, B element crystallized. SEM-EDS results show that Ag and I elements are enriched, while the other elements are evenly distributed. AFM results showed that the sample surface becomes rougher as the iodine content increases in the silver coated silica gel. The FT-IR results show that the structure of the sintered sample is mainly composed of [BiO3], [BiO6] and [BO3]. This study provides a new sintering method by hydration device for the treatment of radioactive iodine waste.


2021 ◽  
pp. 163559
Author(s):  
Sergey G. Anikeev ◽  
Nadezhda V. Artyukhova ◽  
Anastasiia V. Shabalina ◽  
Sergei A. Kulinich ◽  
Valentina N. Hodorenko ◽  
...  

Author(s):  
Gui Gui Peng ◽  
Yi Long Liang ◽  
Wei Li

Abstract The laminated gradient of the SiC reinforced Mg-MMCs has been report few. In this paper, the laminated gradient structure of Mg-3Al-3Sn+xSiC alloys (x=0, 0.5, 1.0 and 2.0 wt %) were prepared via powder metallurgy and spark plasma sintering method, and the effects of different sintering rate (60℃/min, 70℃/min and 80℃/min) on the phase, morphology and corrosion resistance of as-sintered and rolled-state samples with laminated gradient structure are characterized. The results shows that, from the surface to core, the grain size of samples gradually decreased with the contents of SiC addition decreasing. Compared to the as-sintered samples, the micro-hardness of rolled-state reach to 105 HV, and the electrochemical test results shows that corrosion resistance of rolled states samples prepared at 70℃/min increased by 88 %, and the corrosion potential (Ecorr) value is -1.3162 VSCE, which is better than other samples; the samples prepared at 60℃/min increased by 36%, and the samples prepared at 80℃/min only decreased by 5%. It provides a new method to prepare the laminated gradient structure of magnesium alloy composites.


2021 ◽  
Vol 25 (3) ◽  
pp. 17-28
Author(s):  
S. D. Nurherdiana ◽  
T. Gunawan ◽  
N. Widiastuti ◽  
H. Fansuri

Perovskite and metal oxides-based dual-layer hollow fibre membrane (DHF) has a high appeal as separator and catalyst for methane conversion application which operated at intermediate and high temperature. The membrane mostly fabricated via the co-extrusion followed by co-sintering method, which is quite challenging, due to the complexity to handle the barrier between layers from delamination, membrane cracking and crystal structure distortion which affects the material performance in a DHF form. This recent review clarifies the challenges in the DHF fabrication process to regulate physical and chemical properties in terms of mechanical strength, tightness, elemental distribution, and crystal structure stability. The based material of the membrane focuses on NiO-YSZ in the inner layer directly interconnected with LSCF-YSZ in the outer layer. The understanding of the challenges in DHF fabrication, will further reduce crucial errors in the fabrication process and accelerate performance improvement for application such as syngas, methanol and long-chain hydrocarbons production, and solid oxide fuel cell.


2021 ◽  
Vol 2079 (1) ◽  
pp. 012017
Author(s):  
Xiaoli Zhang ◽  
Xiaoyi Zhang ◽  
Yu Yang ◽  
Jiawei Duan ◽  
Liwei Mi

Abstract For Li7La3Zr2O12 (LLZO) solid electrolytes, higher density usually means higher ionic conductivity. Researchers tried many preparation methods to get high density samples and at same times to realize industrial production, low cost, scalable and fast synthesis techniques. In this paper, the mainstream preparation methods of LLZO was given, as polymerized complex method, sol-gel method, field assisted sintering, combustion technique, auto-consolidation method, water-based solvent method. Among these methods, the last four methods can always increase the density to more than 93%. Especially the field assisted sintering method can make the relative density to be high as 99.8%. And all of these methods can make the ion conductivity to be higher than 1.4 × 10-4 S cm-1. Also, most of these methods introduced the Al element into LLZO to realize the liquid sintering.


2021 ◽  
Vol 5 (12(113)) ◽  
pp. 6-19
Author(s):  
Edwin Gevorkyan ◽  
Volodymyr Nerubatskyi ◽  
Volodymyr Chyshkala ◽  
Oksana Morozova

Peculiarities of formation of microstructure in composites based on chemically synthesized zirconium nanopowders obtained by the method of decomposition from fluoride salts were considered. Hydrofluoric acid, concentrated nitric acid, aqueous ammonia solution, metallic zirconium, and polyvinyl alcohol were used. It was established that the reduction of porosity in nanopowders in the sintering process is the main problem in the formation of high-density materials. Analysis of various initial nanopowders, their morphology, and features of sintering by the method of hot pressing with direct transmission of electric current was made. Peculiarities of obtaining the composites based on them with the addition of Al2O3 nanopowders applying the electric sintering method were considered. It was shown that the increase in the content of alumina nano additives leads to an increase in strength and crack resistance of the samples due to simultaneous inhibition of abnormal grain growth and formation of a finer structure with a high content of tetragonal phase. The influence of sintering modes on the formation of the microstructure of zirconium nanopowders has been studied for different contents of alumina additives. Electric current promotes the surface activity of nanopowders and its variable value promotes partial fragmentation of agglomerated grains thus affecting the composite structure. Physical-mechanical properties of the obtained samples, optimal compositions of mixtures, and possibilities of improving some parameters were determined. It was found that nanopowders of zirconium dioxide obtained by the method of decomposition from fluoride salts are quite suitable for the production of composite materials with high physical and mechanical properties. They can compete with imported analogs and enable obtaining of crack resistance of 7.8 MPa·m1/2 and strength of 820 MPa.


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