scholarly journals Cryogenic Milling Method to Fabricate Nanostructured Anodes

2020 ◽  
Vol 3 (11) ◽  
pp. 11285-11292
Author(s):  
Qizhang Yan ◽  
Shu-Ting Ko ◽  
Yumin Zhao ◽  
Grace Whang ◽  
Andrew Dawson ◽  
...  
2020 ◽  
Author(s):  
Qizhang Yan ◽  
Shu-Ting Ko ◽  
Yumin Zhao ◽  
Grace Whang ◽  
Andrew Dawson ◽  
...  

Cryogenic milling was demonstrated as a new and facile method to fabricate nanostructured battery electrode materials. SnSb anode material with 1.2 wt% graphite was selected as a model system to demonstrate the feasibility and benefits of this method. Ball milling at a cryogenic temperature can suppress cold welding, exfoliate bulk graphite powder into nanoplatelets, and evenly disperse them between the grains. Aberration-corrected scanning transmission electron microscopy and post-cycling scanning electron microscopy showed refined grain sizes and well-dispersed carbon nanoplatelets, which can stabilize the nanostructure and alleviate volume expansion and cracking upon cycling. The cryomilled SnSb-C composite anode showed a reversible volumetric capacity of 1842 Ah/L, average coulombic efficiency of 99.6 ± 0.3%, and capacity retention of 90% over 100 cycles. The cryomilled sample showed improved electrochemical performance compared to the conventional ball milled specimen. This new method of cryogenic milling can produce various other high-performance nanostructured electrode materials.


2020 ◽  
Author(s):  
Qizhang Yan ◽  
Shu-Ting Ko ◽  
Yumin Zhao ◽  
Grace Whang ◽  
Andrew Dawson ◽  
...  

Cryogenic milling was demonstrated as a new and facile method to fabricate nanostructured battery electrode materials. SnSb anode material with 1.2 wt% graphite was selected as a model system to demonstrate the feasibility and benefits of this method. Ball milling at a cryogenic temperature can suppress cold welding, exfoliate bulk graphite powder into nanoplatelets, and evenly disperse them between the grains. Aberration-corrected scanning transmission electron microscopy and post-cycling scanning electron microscopy showed refined grain sizes and well-dispersed carbon nanoplatelets, which can stabilize the nanostructure and alleviate volume expansion and cracking upon cycling. The cryomilled SnSb-C composite anode showed a reversible volumetric capacity of 1842 Ah/L, average coulombic efficiency of 99.6 ± 0.3%, and capacity retention of 90% over 100 cycles. The cryomilled sample showed improved electrochemical performance compared to the conventional ball milled specimen. This new method of cryogenic milling can produce various other high-performance nanostructured electrode materials.


2019 ◽  
Vol 1 (1) ◽  
pp. 28-33
Author(s):  
Asghar Kazemzadeh ◽  
Mohammad Ali Meshkat ◽  
Hooman Kazemzadeh ◽  
Mostafa Moradi ◽  
Reza Bahrami ◽  
...  

Author(s):  
A.V. Stomatov ◽  
D.V. Stomatov ◽  
P.V. Ivanov ◽  
V.V. Marchenko ◽  
E.V. Piitsky ◽  
...  

In this work, the authors studied and compared the two main methods used in dental practice for the automated production of orthopedic structures: the widely used CAD / CAM milling method and the 3D printing technology. As an object of research, temporary crowns were used, which were made on the basis of the same digital model: a) by the method of CAD / CAM milling from polymethylmethacrylate disks; b) by 3D printing from photopolymer resin based on LCD technology. Comparison of production methods and finished designs was carried out according to the following characteristics: strength, durability, aesthetic qualities, accuracy of orthopedic designs, etc. According to the results of the study, it was concluded that 3D printing can be a good alternative to CAD / CAM milling in solving problems of temporary prosthetics.


2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.


2018 ◽  
Vol 941 ◽  
pp. 1276-1281
Author(s):  
Anna Terynková ◽  
Jiří Kozlík ◽  
Kristína Bartha ◽  
Tomáš Chráska ◽  
Josef Stráský

Ti-15Mo alloy belongs to metastable β-Ti alloys that are currently used in aircraft manufacturing and Ti15Mo alloy is a perspective candidate for the use in medicine thanks to its biotolerant composition. In this study, Ti15Mo alloy was prepared by advanced techniques of powder metallurgy. The powder of gas atomized Ti-15Mo alloy was subjected to cryogenic milling to achieve ultra-fine grained microstructure within the powder particles. Powder was subsequently compacted using spark plasma sintering (SPS). The effect of cryogenic milling on the microstructure and phase composition of final bulk material after SPS was studied by scanning electron microscopy. Sintering at 750°C was not sufficient for achieving full density in gas atomized powder, while milled material could be successfully sintered at this temperature. Alpha phase particles precipitated during sintering and their size, as well as the size of beta matrix grains, was strongly affected by the sintering temperature.


Friction ◽  
2021 ◽  
Author(s):  
Liangfei Wu ◽  
Zhaozhu Zhang ◽  
Mingming Yang ◽  
Junya Yuan ◽  
Peilong Li ◽  
...  

AbstractRecently, great effort has been devoted to prepare various reinforce fillers to improve polymer performances, but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites. Herein, we engineer raw polyimide (PI) powders with the assistance of polydopamine (PDA) in aqueous solutions. After the modification, polymer powders change from hydrophobic to hydrophilic, which makes it is possible to further modification of polymer powders in liquid phase. During the curing process of modified polymer powders, the partial dehydration of the catechol groups and crosslinking of PDA via C-O-C bonds are confirmed. Based on the features of PDA, a non-destructive mixing method is utilized to realize homogeneous dispersion of multi-walled carbon nanotubes (MWCNTs) in polymer matrix. In comparison with ball milling method, this way can preserve the integrated innate structure of MWCNTs effectively. Besides, by taking full advantage of the reducing and metal-coordination capability of PDA, Cu2+ is successfully loaded onto the surfaces of polymer powders. The related characterizations demonstrate that Cu2+in situ converts to metallic copper rather than copper oxide during the hot pressing process. The tribological properties of corresponding polymer composites are also studied. These results indicate that modifying polymer powders with PDA is multi-profit and presents practical application prospect.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Deshraj Singh ◽  
Pawan Kumar ◽  
Jitendra Singh ◽  
Dharm Veer ◽  
Aravind Kumar ◽  
...  

AbstractComposites proton conducting material based on cesium dihydrogen phosphate (CDP) doped with zirconium oxide (1−x) CsH2PO4/x ZrO2 were synthesized with different concentration having in the range such as x = 0.1, 0.2, 0.3 and 0.4 by ball milling method. The prepared solid acid composites were dried at 150 °C for 6 h. Structural and thermal characterization of solid acid composite proton electrolytes were carried out by X-ray diffractometer, Fourier transform infrared spectroscopy, and Raman spectroscopy respectively. Phase transition of the prepared materials was carried out by using differential scanning calorimetry and conductivity was measured by LC Impedance meter in the range 1 Hz to 400 kHz. The ionic conductivity of ZrO2 doped CsH2PO4 (CDP) was increased up to 1.3 × 10–2 S cm−1 at the 280 °C under environment atmospheric humidification which showed high stability as compared to pure CsH2PO4 (CDP). This obtaining result would be useful for establishing and design the next generation fuel cell.


Author(s):  
Subham Chhetri ◽  
Mohammad Tariq ◽  
Stephen Dilip Mohapatra ◽  
V Vikali Sumi ◽  
Alomi P Zhimomi ◽  
...  

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 88
Author(s):  
Yupeng Xin ◽  
Yuanheng Li ◽  
Wenhui Li ◽  
Gangfeng Wang

Cavities are typical features in aeronautical structural parts and molds. For high-speed milling of multi-cavity parts, a reasonable processing sequence planning can significantly affect the machining accuracy and efficiency. This paper proposes an improved continuous peripheral milling method for multi-cavity based on ant colony optimization algorithm (ACO). Firstly, by analyzing the mathematical model of cavity corner milling process, the geometric center of the corner is selected as the initial tool feed position. Subsequently, the tool path is globally optimized through ant colony dissemination and pheromone perception for path solution of multi-cavity milling. With the advantages of ant colony parallel search and pheromone positive feedback, the searching efficiency of the global shortest processing path is effectively improved. Finally, the milling programming of an aeronautical structural part is taken as a sample to verify the effectiveness of the proposed methodology. Compared with zigzag milling and genetic algorithm (GA)-based peripheral milling modes in the computer aided manufacturing (CAM) software, the results show that the ACO-based methodology can shorten the milling time of a sample part by more than 13%.


Sign in / Sign up

Export Citation Format

Share Document