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Article
Publication date: 11 May 2020

Hsing-I. Hsiang, Chih-Cheng Chen, Liang-Fang Fan and Hao-Yin Cheng

The interaction between the silver powder and organic vehicle largely determines the rheological behavior of silver conductive paste. This study aims to prepare silver

Abstract

Purpose

The interaction between the silver powder and organic vehicle largely determines the rheological behavior of silver conductive paste. This study aims to prepare silver conductive paste with an organic vehicle system consisting of ethyl cellulose (EC) and terpineol/butyl carbitol acetate solvent mixtures. The study also aims to measure the rheological behaviors of the silver conductive pastes with different solvent mixtures, EC molecular weights and silver content, to investigate the interaction among the polymer, solvent and silver powder and determine the main factors affecting the thixotropic index and maximum silver content.

Design/methodology/approach

The rheological behaviors of silver conductive pastes with different solvent mixtures, EC molecular weights and silver content were investigated using viscometer.

Findings

The shear thinning became significant with increasing EC molecular weight. The EC solvation with higher molecular weight in solvent is better than that of EC with lower molecular weight. This leads to a stronger interaction between the silver powder and EC with higher molecular weight and consequently good silver particle dispersion. The relative viscosity of silver conductive paste at 10 s−1 increases significantly with increasing silver content, but the relative viscosity at 100 s−1 is much less sensitive to the silver content. The viscosities at low and high shear rate can be increased by increasing the silver content and EC molecular weight, respectively.

Originality/value

The interaction among the polymer, solvent and silver powder was investigated for the silver paste with high solid content. The main factors affecting the viscosities at high and low shear rates, thixotropic index and maximum silver content were determined.

Details

Circuit World, vol. 47 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 1 February 1963

R.R. Benham

The choice of electrodeposited silver solely because of its corrosion resistance is infrequent since a thick deposit to overcome porosity is necessary. Nevertheless, its…

Abstract

The choice of electrodeposited silver solely because of its corrosion resistance is infrequent since a thick deposit to overcome porosity is necessary. Nevertheless, its anti‐corrosive properties are important in the very many applications in which it is used where this is not the first consideration. This article discusses modern techniques in plating which result in quicker plating times for a given thickness and describes methods for the reduction of tarnish. Trends and developments are reviewed.

Details

Anti-Corrosion Methods and Materials, vol. 10 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 22 May 2007

Jing Li Fang and Daniel K. Chan

This study seeks to examine the advantages of mildly alkaline immersion silver as a final finish for solderability in order to combat the shortcomings of acidity in some…

Abstract

Purpose

This study seeks to examine the advantages of mildly alkaline immersion silver as a final finish for solderability in order to combat the shortcomings of acidity in some popular immersion silver solutions.

Design/methodology/approach

The paper describes in detail the necessary steps in the mildly alkaline immersion silver process.

Findings

The process can overcome the problems of conventional acidic immersion silvers, especially in thermal shock and stress testing. Also it does not affect soldering or aluminium wire bonding.

Originality/value

This is arguably a pioneering study in that it posits the benefits of mildly alkaline immersion silver as a final finish for solderability.

Details

Circuit World, vol. 33 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 1 March 1999

P. Bratin, Michael Pavlov and Gene Chalyt

This paper extends our study of the sequential electrochemical reduction analysis (SERA) technique for evaluation of various alternative finishes and it discusses the…

Abstract

This paper extends our study of the sequential electrochemical reduction analysis (SERA) technique for evaluation of various alternative finishes and it discusses the application of the SERA technique to assess the surface conditions of the silver finish. The tarnishing products of the silver formed under ambient and artificially created conditions were analyzed, the protective effect of an anti‐ tarnishing film was evaluated, and the influence of the elevated temperatures (reflow) on the stability of the organic inhibitor and the formation of the tarnishing film will be shown.

Details

Circuit World, vol. 25 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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Expert briefing
Publication date: 15 February 2021

It lost almost all of this gain the following day, but remains broadly on an upward trend, after the price gained nearly 50% in 2020.

Details

DOI: 10.1108/OXAN-DB259524

ISSN: 2633-304X

Keywords

Geographic
Topical
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Book part
Publication date: 20 November 2018

Ricardo Solis Rosales

This essay explores the critical vision of Francisco Barrera Lavalle about the Mexico’s Monetary Reform of 1905. In his critique, Barrera inserts an argument about the…

Abstract

This essay explores the critical vision of Francisco Barrera Lavalle about the Mexico’s Monetary Reform of 1905. In his critique, Barrera inserts an argument about the nature of the balance of payments in the Mexican economy: the disequilibria in Mexico’s trade balance were structurally recurrent given the characteristics of what the country exports: commodities and raw materials. Barrera believed that the authorities made the mistake of overvaluing the peso, assigning it a value higher than what silver currency was worth at the time on international markets. Barrera also dismissed the idea that monetary stability could be achieved by suspending the free coinage of silver currency. Finally, Barrera held that banks should be obligated to pay their banknotes in gold, as they were in Great Britain and in the United States, not in silver coins.

Details

Including a Symposium on Latin American Monetary Thought: Two Centuries in Search of Originality
Type: Book
ISBN: 978-1-78756-431-2

Keywords

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Book part
Publication date: 8 November 2003

Elizabeth Emma Ferry

This essay uses Marx’s concept of commodity fetishism and Mauss’s description of the hau as the spirit that connects the giver to the gift to examine notions of…

Abstract

This essay uses Marx’s concept of commodity fetishism and Mauss’s description of the hau as the spirit that connects the giver to the gift to examine notions of production, value, and collectivity in the Santa Fe silver mining Cooperative in Guanajuato, Mexico. This case allows us to look at how fetishism on the one hand, and “hauism” on the other, can work together to form a hybrid form of value wherein silver participates in both commodified and giftlike processes. More broadly, it helps us to examine the relationship between the production of value and the production and legitimation of social groups.

Details

Anthropological Perspectives on Economic Development and Integration
Type: Book
ISBN: 978-0-76231-071-5

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Article
Publication date: 4 November 2019

Hualiang Huang and Furong Bu

The purpose of this study is to provide a theoretical basis for the study of the galvanic corrosion mechanism of copper coupled silver-coating under a thin electrolyte…

Abstract

Purpose

The purpose of this study is to provide a theoretical basis for the study of the galvanic corrosion mechanism of copper coupled silver-coating under a thin electrolyte layer in electronic systems.

Design/methodology/approach

Electrochemical measurements and surface characterizations.

Findings

The results indicate that the potential difference between copper and silver electrodes first quickly increases, and then reaches a relatively stable and large value with the extension of the immersion time. With the significant increase in the cathode/anode area ratio in electronic systems, the area ratio effect obviously accelerates the corrosion of copper due to the remarkable promotion of the cathode process. For a large cathode/anode area ratio, the galvanic current density always maintains a large value and exhibits an increasing trend with the extension of the immersion time, which is attributed that the area ratio effect reduces the protection of corrosion products. For the same area of cathode and anode, the galvanic current density always maintains a small value with the extension of the immersion time due to a low galvanic effect and protective corrosion products.

Practical implications

This work provides some information for the establishment of reliably protective measures for electronic systems in service.

Social implications

This work not only provides some information for the establishment of reliably protective measures for electronic systems in service, but also provides a theoretical basis for the selection of metal materials in microelectronic systems.

Originality/value

This work provides not only a theoretical basis for the study of the galvanic corrosion mechanism of Cu/Ag under a thin electrolyte layer, but also provides some information for the establishment of reliably protective measures for electronic systems in service.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 5 December 2019

Yansong Tan, Xin Li, Xu Chen, Zhenwen Yang and Guo-Quan Lu

This paper aims to use nano-silver paste to design a new bonding method for super-large-area direct-bonded-aluminum (DBA) plates. It compared several frequently used…

Abstract

Purpose

This paper aims to use nano-silver paste to design a new bonding method for super-large-area direct-bonded-aluminum (DBA) plates. It compared several frequently used bonding methods and proved the feasibility of an optimized low-pressure-assisted double-layer-printed silver sintering technology for large-area bonding to increase the thermal conductivity of power electronic modules with high junction temperature, higher power density and higher reliability.

Design/methodology/approach

The bonding profile was optimized by using transparent glasses as substrates. Thus, the bonding qualities could be directly characterized by optical observation. After sintering, the bonded DBA samples were characterized by nondestructive X-ray computed tomography system, scanning electron microscopy equipped with an energy dispersive spectrometer. Finally, bonding stress evolution was characterized by shear tests.

Findings

Low-pressure-assisted large-area double-layer-printed bonding process consisting of six-step was successfully developed to bond DBA substrates with the size of 50.8 × 25.4 mm. The thickness of the sintered-silver bond-line was between 33  and 74 µm with the average porosity of 12.5 per cent. The distribution of shear strength along the length of DBA/DBA bonded sample was from 9.7  to 18.8 MPa, with average shear strength of 15.5 MPa. The typical fracture primarily propagated in the sintered-silver layer and partially along the Ni layer.

Research limitations/implications

The bonding stress needs to be further improved. Meanwhile, the thermal and electrical properties are encouraged to test further.

Practical implications

If nano-silver paste can be used as thermal interfacial material for super-large-area bonding, the thermal performance will be improved.

Social implications

The paper accelerated the use of nano-silver paste for super-large-area DBA bonding.

Originality/value

The proposed bonding method greatly decreased the bonding pressure.

Details

Soldering & Surface Mount Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 2 September 2019

Margarita Ivanovna Skiba and Viktoria Vorobyova

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium…

Abstract

Purpose

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium low-temperature plasma in presents polysorbate-80 and to assess their antibacterial activity in composite materials (beads) for water treatment process.

Design/methodology/approach

Silver nanoparticles were prepared in aqueous AgNO3 solution by using of contact non-equilibrium low-temperature plasma in the present of nonionic surfactant polysorbate-80 (Tween 80) as capping agent. Ultraviolet–visible (UV) spectroscopy, X-ray diffraction and zeta potential analysis were used to study the formation and properties of silver nanoparticles.

Findings

The formation of silver colloidal solutions in the presence of capping agent under plasma discharge is characterized by the presence of peak λmax = 380 – 402 nm in the spectra. The addition of sodium alginate into the reaction mixture allows synthesizing stable colloidal silver solutions. The average size of formed silver particles is up to 50 nm. Ag NPs exhibited an excellent bactericidal activity against both gram-positive and gram- negative bacteria. Composite beads prepared using nonionic surfactant were found to be effective in disinfecting the Staphylococcus aureus to different extents.

Research limitations/implications

Further studies are necessary for confirmation of the practical application, especially of the toxicity of Ag NPs, as well as the sorption properties of the alginate beads with Ag NPs.

Practical implications

The method provides a simple and practical solution to improving the synthesis of colloidal solutions of Ag NPs for water treatment process.

Originality/value

Contact nonequilibrium low-temperature plasma can be used as an effective technique for synthesis of nanomaterials.

Details

Pigment & Resin Technology, vol. 48 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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