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Improved sinter-bonding properties of silver-coated copper flake paste in air by the addition of sub-micrometer silver-coated copper particles

Publication date: November–December 2020

Source: Journal of Materials Research and Technology, Volume 9, Issue 6

Author(s): Myeong In Kim, Eun Byeol Choi, Jong-Hyun Lee

Republished by Plato

Published

on

open access

Abstract

To promptly form a bondline with high thermal stability and thermal conductivity using a small amount of expensive Ag, dies were attached to Ag finishes by pressure-assisted sinter bonding at 300 °C using micrometer-sized Ag-coated Cu ([email protected]) flakes. Small [email protected] particles of 350 nm size were also added to the paste to increase the sinterability by increasing the contact points, which resulted in a bimodal paste. The dewetting of the Ag shells in [email protected] induced initial sintering, and the rearrangement of the 350 nm [email protected] particles as well as the bending of the [email protected] flakes under pressure effectively filled the voids between the particles. As a result, shear strengths of almost 20 MPa and 28.9 MPa were obtained after only 1 and 5 min of sinter bonding, respectively. In addition, a bondline with a unique near full density microstructure was achieved in the 5 min sinter-bonded sample.

Keywords

Ag-coated Cu flake

Sinter-bonding paste

Bimodal particle

Bending deformation

Shear strength

© 2020 The Author(s). Published by Elsevier B.V.

Source: https://www.sciencedirect.com/science/article/pii/S2238785420320354?dgcid=rss_sd_all

Material

Synthesis and optical properties of alizarin yellow GG-Cu(II)-PVA nanocomposite film as a selective filter for optical applications

Publication date: Available online 4 January 2021

Source: Journal of Materials Research and Technology

Author(s): Mona M. Khalil, Adly H. El-Sayed, M.S. Masoud, E.M. Mahmoud, Mahmoud A. Hamad

Republished by Plato

Published

on


Elsevier

Available online 4 January 2021

Journal of Materials Research and Technology

open access

Abstract

In this paper, alizarin yellow GG (AYGG) – CuCl2 doped with polyvinyl alcohol (PVA) has been successfully synthesized. This composite has spherical shape particles with amorphous structure. Thermal analysis indicates that there is an endothermic change, which is related to the glass transition. In addition, the coordination between the transition metal Cu(II) ion and AYGG (ligand) occurs via oxygen atoms of phenolic hydroxyl groups and a nitrogen atom of azo moiety from the two ligand molecules. AYGG – Cu(II) doped PVA has high dispersion for high frequency lights and vice versa for low frequency lights. Therefore, it is concluded that AYGG – Cu(II) doped PVA film is suggested as a selective filter for ultraviolet and high frequency visible lights for many optical applications like protective shields for solar cells and packaging.

Keywords

Alizarin yellow GG

UV-Vis spectra

FTIR spectra

refractive index

© 2021 The Author(s). Published by Elsevier B.V.

Source: https://www.sciencedirect.com/science/article/pii/S2238785420321815?dgcid=rss_sd_all

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Material

Factors affecting the formation of plasma on Fe, Cu and W electrodes using an electrochemical reaction in an aqueous environment with high-voltage DC

Publication date: Available online 5 January 2021

Source: Journal of Materials Research and Technology

Author(s): Tran Van Cong, Nguyen Duc Hung, Lai Xuan Bach, Tran van Hung, Nam Nguyen Dang

Republished by Plato

Published

on


Elsevier

Available online 5 January 2021

Journal of Materials Research and Technology

open access

Highlights

Formation of plasma on Fe, Cu and W electrodes using electrochemical reaction in aqueous environment.

Plasma appears at a high voltage of about 15 kV with the earliest appearance on W electrode.

Water-soluble plasma on W electrode produces more gases than those in Fe and Cu electrodes.

The size of Cu and Fe nanoparticles is approximate 200 nm, whereas 100 and 500 nm were for W.

Abstract

Plasma creation technology in an aqueous environment is being evaluated for research and practical applications, particularly in the field of materials and nano processing, as well as environmental pollution treatment. Important factors that influence the appearance of plasma when performing electrolysis by high-voltage DC (direct current) in aqueous environments are voltage, distance between electrodes, pH, conductivity and ambient temperature, as well as the nature of the electrode, which has been suggested by concurrent works to be the controlling factor of the other ones. Specifically, it is indicated that the plasma typically appears at a high voltage of about 15 kV and a distance between electrodes of 200 mm, with the earliest appearance occurring with the tungsten (W) electrode. Additionally, pH, conductivity and temperature variations for effective plasma creation have been found in all investigated electrodes. Finally, it has been found that the water-soluble plasma on the W electrode produces more gas than those in iron (Fe) and copper (Cu) electrodes. After the reactions, the lowest dissolution belonging to W electrode could be attributed to the inertness of W in comparison with Fe and Cu, resulting in a minimal value of the zeta potential. In addition, the size of Cu and Fe nanoparticles achieved in the investigated solution was approximately 200 nm, whereas W nanoparticles were two separate sizes of 100 and 500 nm. Therefore, this work could offer the needed agency for technological applications in industrial wastewater treatment and high-purity nanoparticle fabrication.

Keywords

Plasma electrode

Copper

Iron

Tungsten

High voltage electrochemistry

© 2021 The Author(s). Published by Elsevier B.V.

Source: https://www.sciencedirect.com/science/article/pii/S2238785420321748?dgcid=rss_sd_all

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Material

Selenium nanoparticles synthesized using an eco-friendly method: Dye decolorization from aqueous solutions, cell viability, antioxidant, and antibacterial effectiveness

Publication date: Available online 5 January 2021

Source: Journal of Materials Research and Technology

Author(s): Badreah A. Al Jahdaly, Najlaa S. Al-Radadi, Ghada M.G. Eldin, Albandary Almahri, M.K. Ahmed, Kamel Shoueir, Izabela Janowska

Republished by Plato

Published

on


Elsevier

Available online 5 January 2021

Journal of Materials Research and Technology

open access

Abstract

Selenium nanoparticles (SeNPs) were fabricated using a green microwave technique in the presence of ascorbic acid. The morphological features indicated that the semi-spherical SeNPs with a diameter 8.5-22nm were configured in agglomerated spherical shapes with diameters around 0.47-0.71 μm. Furthermore, the removal of Fuchsin Basic dye from aqueous solutions was investigated upon variation of concentration of SeNPs. The degradation efficiency achieved 100 % for 10 mg of SeNPs after 34 min of visible light irradiation time. The antioxidant activity was tested via DPPH radical scavenging assay and displayed that the highest scavenging capacity (311.1±15.72 mg/g) was achieved by SeNPs at a concentration of 106.25 mg/mL. Otherwise, the cell viability of SeNPs through human fibroblasts cell lines in-vitro was reduced to be 75.1±3.8 % with nanoparticle concentration around 500 μg/mL. The antibacterial activity was investigated against gram-negative and gram-positive bacteria such as Escherichia coli (E.coli), Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumonia), Staphylococcus aureus (S. aureus), and Bacillus subtilis (B. subtilis) bacteria after one day of exposure. It was illustrated that SeNPs did not display an activity towards Staphylococcus aureus, while it possessed the highest one against Escherichia coli with MBC of 50 ± 1.76 μg/mL compared with 26 ± 0.6 μg/mL for the standard antibiotic. These tremendous properties of SeNPs indicate that manipulating multifunctional nanoparticles for versatile wound and skin treatment applications is highly encouraging.

Keywords

SeNPs

ascorbic acid

dye removal

antibacterial

antioxidant

© 2020 Published by Elsevier B.V.

Source: https://www.sciencedirect.com/science/article/pii/S2238785420321761?dgcid=rss_sd_all

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