scholarly journals Wetting and brazing of YIG ceramics using Ag-CuO-TiO2 metal filler

Author(s):  
Wanqi Zhao ◽  
Shuye Zhang ◽  
Jian Yang ◽  
Tiesong Lin ◽  
Dusan P. Sekulic ◽  
...  
Keyword(s):  
POROS ◽  
2018 ◽  
Vol 15 (2) ◽  
pp. 101
Author(s):  
Andika Wisnujati

Abstract: In general, water vehicles or water transport commonly called canoes are still used in villages for fishermen to fish in the sea and in rivers. Aluminum alloy in this research using Aluminum series 5. Background of this research is to analyze the strength of TIG weld (Tungsten Inert Gas) connection in the canoe to get reliable samples and no leakage. In high TIG welding the low temperature is determined by the high-low of the electric current being flowed. The aluminum plate for the canoe is subjected to material composition testing and tensile testing to determine the physical and mechanical properties of the TIG welding joints on the aluminum series 5. TIG welding with the current variable 65, 70 and 75 Ampere. Testing specimens of 2mm thick with dimensions of 24x16 cm where the electric arc flame is generated by tungsten electrodes (non-feeding electrodes) with metal workpieces. Test results obtained include that welding on aluminum series 5 is done with AC current (Alternating Current) due to the action of cleaning the metal surface is greater. Thin metal work, TIG welding can be used without metal filler. Material composition test showed that aluminum content of 97,76% and magnesium main addition element equal to 1.753%. In tensile testing, the strong variations of current used to connect aluminum plates are 65, 70, and 75 Ampere produce different tensile strength. The highest tensile strength is generated on plate grafting using a strong current of 75 Ampere with a yield of 165.91 MPa. This is because with a strong current of 75 A, the welding liquid enters and fuses into the center of the aluminum, resulting in a strong welding joint. 


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2038
Author(s):  
Arfat Anis ◽  
Ahmed Yagoub Elnour ◽  
Mohammad Asif Alam ◽  
Saeed M. Al-Zahrani ◽  
Fayez AlFayez ◽  
...  

Metal-plastic composites have the potential to combine enhanced electrical and thermal conductivity with a lower density than a pure metal. The drawback has often been brittleness and low impact resistance caused by weak adhesion between the metal filler and the plastic. Based on our observation that aluminum foil sticks very strongly to poly(ethylene terephthalate) (PET) if it is used as a backing during compression moulding, this work set out to explore PET filled with a micro and a nano aluminum (Al) powder. In line with other composites using filler particles with low aspect-ratio, the tensile modulus increased somewhat with loading. However, unlike most particle composites, the strength did not decrease and most surprisingly, the Izod impact resistance increased, and in fact more than doubled with certain compositions. Thus, the Al particles acted as a toughening agent without decreasing the modulus and strength. This would be the first case where addition of a metal powder to a plastic increased the modulus and impact resistance simultaneously. The Al particles also acted as nucleating agents but it was not sufficient to make PET crystallize as fast as the injection moulding polyester, poly(butylene terephthalate) (PBT).


Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1956 ◽  
Author(s):  
Oleksandr Grytsenko ◽  
Ivan Gajdoš ◽  
Emil Spišák ◽  
Volodymyr Krasinskyi ◽  
Oleh Suberlyak

The synthesis and study of metal-containing hydrogels, particularly those filled with nickel nanoparticles, is currently of interest to many researchers. This paper presents the results of an investigation of the structure and properties of Ni(0)-filled composites on the basis of 2-hydroxyethylmethacrylate copolymers (HEMA) with polyvinylpyrrolidone (PVP) and their hydrogels. The authors of the article are the first who propose the method to produce these materials by combining the processes of polymer matrix synthesis and a reduction of Ni2+ ions. Synthesis is carried out in one stage without complicated equipment and is technologically simple. It is determined by thermometric research that the temperature conditions required for the chemical reduction of Ni2+ are achieved due to the heat released during the exothermic reaction of HEMA polymerization in the presence of PVP. With the help of Fourier transform infrared analysis, and thermogravimetric and differential-thermal analysis, the formation of a crosslinked graft copolymer based on HEMA and PVP was confirmed, and its structural parameters, including the efficiency of PVP grafting, PVP content in the copolymer, and the molecular weight of the interstitial fragment of the polymer network, were investigated. The results obtained with scanning electron microscopy revealed that the size of the Ni(0) particles is about 500 nm. X-ray structural analysis of the composites obtained confirmed the existence of metal nickel particles. The strength, elastic, sorption, electrical, and magnetic properties of the obtained composites in the solid (dry) and elastic (swollen) physical states, depending on the composition of the copolymer and the content of the metal filler, have been investigated.


2019 ◽  
Vol 56 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Alina-Ruxandra Caramitu ◽  
Sorina Mitrea ◽  
Virgil Marinescu ◽  
George-Andrei Ursan ◽  
Mihaela Aradoaie ◽  
...  

HDPE composite samples with aluminum and iron nanopowders were made by extrusion and injection. Samples of material obtained were characterized by comparative determinations of dielectric spectroscopy and SEM microscopy. SEM images have indicated that the agglomerations of the powders used are persistent, do not decompose during extrusion and injection processing. Determinations by dielectric spectroscopy indicated that HDPE composite materials with metal nanopowder filler have higher dielectric losses than pure HDPE (reference). The highest increases in tgd up to 2.6 times, were recorded for 50 nm nanopowders with specific high surface area (over 20 m2 / g). The electrical conductivity of the investigated samples increases with increasing frequency, both for pure HDPE and for HDPE with metal powder filler. As a result of the film effect in the HDPE case with metal filler, the increases in the high frequencies range are lower than in the extremely low frequencies range.


2020 ◽  
Author(s):  
Christopher DelRe ◽  
Junpyo Kwon ◽  
Philjun Kang ◽  
Le Ma ◽  
Aaron Hall ◽  
...  

AbstractMany bioactive elements, long perceived as non-viable for material development, are now emerging as viable building blocks to encode material lifecycle and to ensure our harmonious existence with nature. Yet, there is a significant knowledge gap on how bio-elements interface with synthetic counterparts and function outside of their native environments. Here, we show that when enzymes are dispersed as nanoclusters confined within macromolecular matrices, their reaction kinetics, pathway, and substrate selectivity can be modulated to achieve programmable polymer degradation down to repolymerizable small molecules. Specifically, when enzyme nanoclusters are dispersed in trace amount (~0.02 wt%) in polyesters, i.e. poly(caprolactone) (PCL) and poly(lactic acid) (PLA), chain-end mediated processive depolymerization can be realized, leading to scalable bioactive plastics for efficient sorting, such as recovery of precious metal filler from flexible electronics. Present studies demonstrate that when the enzyme is confined at dimensions similar to that of polymer chains, their behaviors are governed by the polymer conformation, segmental dynamic and thermal history, highlighting the importance to consider bioactive plastics differently from solution enzymology.


Microscopy ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 291-297
Author(s):  
Masaki Okada ◽  
Daiya Sasaki ◽  
Hideo Kohno

Abstract Y-branched or side-by-side-branched carbon microtubes with metal filler material were fabricated, and material transport in the branched microtubes with Joule heating was investigated using in situ scanning electron microscopy with micro-electrode probes. When a voltage and electric current were applied, the material enclosed in the microtubes moved from its original position. The movement was not related to the direction of the electric current; therefore, it is concluded that the movement was not due to electromigration, but rather a temperature gradient, volume expansion and increased vapor pressure by Joule heating. In Y-branched microtubes, a part of the metal filler material moved from one branch to another branch, which would be useful for microfluidic flow switching. A cylindrical filler material was also observed to be expelled from a branch while its shape was maintained, and this phenomenon is presumably caused by vaporization-induced high pressure and could find application in micro-mechanical manipulators such as punching needles. In side-by-side-branched carbon microtubes, Joule heating caused thermal volume expansion to fill the spaces in the branches that were initially empty. The microtubes then reverted to a state almost identical to the initial state with empty spaces when the electric current was turned off. These results suggest that thermal volume expansion could be employed for flow switching.


2007 ◽  
Vol 42 (17) ◽  
pp. 7324-7330 ◽  
Author(s):  
S. A. Pande ◽  
D. S. Kelkar ◽  
D. R. Peshwe

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