scholarly journals Effects of Bismuth on the Microstructure, Properties, and Interfacial Reaction Layers of Sn-9Zn-xBi Solders

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 538
Author(s):  
Yan Zhi Peng ◽  
Cai Ju Li ◽  
Jiao Jiao Yang ◽  
Jia Tao Zhang ◽  
Ju Bo Peng ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Oxidation Resistance ◽  
Interfacial Reaction ◽  
Solidus Temperature ◽  
Antioxidant Properties ◽  
Melting Behavior ◽  
Inhibitory Effect ◽  
Spreading Rate ◽  
Free Solder ◽  
Positive Effect

In electronic packaging, Sn-Zn lead-free solder has great application prospects. Sn-9Zn-xBi alloys were obtained by smelting. This paper details a systematic study of the effect of Bi on the microstructure, melting behavior, wettability, mechanical behavior, antioxidant properties, and electrical conductivity of Sn-9Zn-xBi alloy, as well as the interfacial reaction in Sn-9Zn-xBi/Cu joints. The coarse Zn-rich phase became larger with an increase in the addition of Bi, which is harmful to the oxidation resistance of the solders. The melting temperature, solidus temperature, and liquidus temperature decreased with the increase in the addition of Bi, but the melting range increased. Adding a proper amount of Bi could substantially improve the spreading rate of Sn-9Zn, but reduce its oxidation resistance. Because of the solid solution effect of Bi element, the tensile strength of the Sn-9Zn solders could be enhanced, but the plastic and electrical conductivity was decreased. The IMC layer of the Sn-9Zn and Cu joints consisted of the ε-CuZn5 phase and the γ-Cu5Zn8 phase. With an increase in the Bi element, the thickness of the interfacial reaction layer was firstly increased. When the Bi element content exceeded 3 wt.%, the inhibitory effect of the aggregated Bi elements on the formation of IMC was greater than the positive effect of the longer reaction time, and the thickness of the IMC decreased.

Melting behavior and oxidation resistance of Ce–Sn alloy designed for lead-free solder manufacturing

2016 ◽  
Vol 125 (3) ◽  
pp. 1009-1015 ◽  
Author(s):  
Marian Drienovsky ◽  
Lydia Rizekova Trnkova ◽  
Milan Ozvold ◽  
Ivona Cernickova ◽  
Marian Palcut ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Melting Behavior ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

scholarly journals Chemical Composition, In Vitro and In Silico Antioxidant Potential of Melissa officinalis subsp. officinalis Essential Oil

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1081
Author(s):  
Matilda Rădulescu ◽  
Călin Jianu ◽  
Alexandra Teodora Lukinich-Gruia ◽  
Marius Mioc ◽  
Alexandra Mioc ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Chemical Composition ◽  
Essential Oil ◽  
In Silico ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Inhibitory Effect ◽  
Melissa Officinalis ◽  
Β Carotene

The investigation aimed to study the in vitro and in silico antioxidant properties of Melissa officinalis subsp. officinalis essential oil (MOEO). The chemical composition of MOEO was determined using GC–MS analysis. Among 36 compounds identified in MOEO, the main were beta-cubebene (27.66%), beta-caryophyllene (27.41%), alpha-cadinene (4.72%), caryophyllene oxide (4.09%), and alpha-cadinol (4.07%), respectively. In vitro antioxidant properties of MOEO have been studied in 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging, and inhibition of β-carotene bleaching assays. The half-maximal inhibitory concentration (IC50) for the radical scavenging abilities of ABTS and DPPH were 1.225 ± 0.011 μg/mL and 14.015 ± 0.027 μg/mL, respectively, demonstrating good antioxidant activity. Moreover, MOEO exhibited a strong inhibitory effect (94.031 ± 0.082%) in the β-carotene bleaching assay by neutralizing hydroperoxides, responsible for the oxidation of highly unsaturated β-carotene. Furthermore, molecular docking showed that the MOEO components could exert an in vitro antioxidant activity through xanthine oxidoreductase inhibition. The most active structures are minor MOEO components (approximately 6%), among which the highest affinity for the target protein belongs to carvacrol.

scholarly journals Ultrahigh Oxidation Resistance and High Electrical Conductivity in Copper-Silver Powder

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jiaxiang Li ◽  
Yunping Li ◽  
Zhongchang Wang ◽  
Huakang Bian ◽  
Yuhang Hou ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Oxidation Resistance ◽  
Silver Powder ◽  
High Electrical Conductivity

scholarly journals Enhancement of Oxidation Resistance of Copper by an Organic Thin Layer and its Influence on Electrical Conductivity

2016 ◽  
Vol 73 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Takuya IKEDA ◽  
Tomoki TAKATA ◽  
Juri TAKAGI ◽  
Kaoru ADACHI ◽  
Yasuhisa TSUKAHARA
Keyword(s):  
Electrical Conductivity ◽  
Thin Layer ◽  
Oxidation Resistance

scholarly journals Development of Biodegradable Whey-Based Laminate Functionalised by Chitosan–Natural Extract Formulations

2020 ◽  
Vol 21 (10) ◽  
pp. 3668
Author(s):  
Sanja Potrč ◽  
Lidija Fras Zemljič ◽  
Meta Sterniša ◽  
Sonja Smole Možina ◽  
Olivija Plohl
Keyword(s):  
Antimicrobial Activity ◽  
Oxygen Permeability ◽  
Surface Composition ◽  
Antioxidant Properties ◽  
Chitosan Nanoparticles ◽  
Barrier Properties ◽  
Penicillium Verrucosum ◽  
Natural Extracts ◽  
Positive Effect ◽  
Macromolecular Solution

In this research, antimicrobial polysaccharide chitosan and natural extracts were used as surface coating of a plastic laminate with an integrated whey layer on the inside. The aim was to establish the biodegradable and active concept of packaging laminates. For this purpose, chitosan nanoparticles (CSNPs) with embedded rosemary or cinnamon extracts were synthesised and characterised. Additionally, a whey-based laminate was functionalised: i) chitosan macromolecular solution was applied as first layer and ii) cinnamon or rosemary extracts encapsulated in CSNPs were applied as upper layer (layer wise deposition). Such functionalised whey-based laminate was physicochemically characterized in terms of elemental surface composition, wettability, morphology and oxygen permeability. The antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, Aspergillus flavus and Penicillium verrucosum. The antioxidant properties were determined using the ABTS assay. It could be shown that after functionalization of the films with the above-mentioned strategy, the wettability was improved. Furthermore, such whey-based laminates still show excellent barrier properties, good antimicrobial activity and a remarkable antioxidative activity. In addition to the improved biodegradability, this type of lamination could also have a positive effect on the shelf-life of products packaged in such structured films.

scholarly journals The use of wild medicinal raw materials in food production

2020 ◽  
Vol 17 ◽  
pp. 00048
Author(s):  
Alla V. Volkova ◽  
Vladimir N. Sysoev ◽  
Andrey N. Makushin
Keyword(s):  
Food Production ◽  
Raw Materials ◽  
Inhibitory Effect ◽  
Bakery Products ◽  
Systematic Analysis ◽  
Experimental Justification ◽  
Carbonated Drinks ◽  
Herbal Infusions ◽  
Positive Effect ◽  
Water Alcohol

Research on the composition of new types of food products, including those enriched with physiologically functional ingredients, is relevant and promising, since it allows us to organize public nutrition on a scientific and hygienic basis. The aim is experimental justification of the use of wild medicinal raw materials in food production. The methodological basis is a systematic analysis of the technology for the production of bakery products, non-alcoholic carbonated drinks and poultry sausages enriched with wild medicinal raw materials. In accordance with the chosen method, the problem of choosing and justifying the use of wild-growing phyto-enrichment agents of different species has been solved. It has been established that the introduction of phyto-enrichment agents has a positive effect on maturation processes of the dough. The use of wild medicinal raw materials is more justified in the form of herbal infusions. In the production of non-alcoholic carbonated drinks, drinks containing hawthorn, echinacea grass, linden flowers, lingonberry leaves, rose hips and thyme herbs have the most harmonious taste. In the production of sausages, wild-growing medicinal raw materials can be used as water-alcohol infusions and crushed raw materials. A water-alcohol infusion of fireweed narrow-leaved has the greatest inhibitory effect on the development of bacteria.

A transparent embedded Cu/Au-nanomesh electrode on flexible polymer film substrates

RSC Advances ◽  
2016 ◽  
Vol 6 (95) ◽  
pp. 92970-92974 ◽  
Author(s):  
Pil-Hoon Jung ◽  
Yang Doo Kim ◽  
Hak-Jong Choi ◽  
Young Hoon Sung ◽  
Heon Lee
Keyword(s):  
Electrical Conductivity ◽  
Mechanical Strength ◽  
Polymer Film ◽  
Oxidation Resistance ◽  
Transparent Electrodes ◽  
Flexible Polymer ◽  
Embedded Structure ◽  
Flexible Transparent Electrodes

We report transparent embedded Cu/Au-nanomesh electrodes with high transmittance and electrical conductivity. Their embedded structure also endows these flexible transparent electrodes with oxidation resistance and good mechanical strength.

Effects of Organic Acids on Wettability of Sn-0.3Ag0.7Cu Lead-Free Solder

2014 ◽  
Vol 543-547 ◽  
pp. 3843-3847
Author(s):  
Ming Tang ◽  
Gui Sheng Gan ◽  
Hu Luo ◽  
Shu De Gan ◽  
Qing Meng Wang ◽  
...  
Keyword(s):  
Organic Acid ◽  
Adipic Acid ◽  
Spreading Rate ◽  
Lead Free ◽  
Mass Ratio ◽  
Strong Activity ◽  
Average Spreading ◽  
Free Solder ◽  
Spreading Rates ◽  
Lead Free Solders

In the assembly of electronic products, developing good organic acid fluxes plays an important role in improving the solderability of lead-free solders. In this paper, a variety of fluxes containing 5% (mass fraction) organic acid activators were prepared. Effects of different activators on the spreading rates of Sn-0.3Ag0.7Cu solder were studied. The results show that: activity of monobasic acids are weak except for benzoic acid; dibasic acids and polybasic acids have relatively strong activity but serious corrosion and slightly less activity persistence. Compounding palmitic acid and adipic acid in the mass ratio of 1:2 as the activator, the average spreading rate of Sn-0.3Ag0.7Cu solder is 71.11% in maximum. Compounding succinic acid and adipic acid in the mass ratio of 3:7 as the activator, the average spreading rate is up to 72.49% in maximum. And solder spots are in-erratic, bright and plump, meeting the quality requirements of electronic micro-connection.

Advanced Welding Materials and Technologies for Repair of Turbine Engine Components Manufactured of High Gamma Prime Nickel Based Superalloys

2018 ◽  
Author(s):  
Alexandre Gontcharov ◽  
Yuan Tian ◽  
Paul Lowden ◽  
Robert Tollett ◽  
Mathieu Brochu
Keyword(s):  
Rupture Strength ◽  
Solidus Temperature ◽  
Stress Rupture ◽  
Melting Behavior ◽  
Turbine Engine ◽  
Weld Microstructure ◽  
Gamma Prime ◽  
High Gamma ◽  
Engine Components ◽  
Welding Materials

The current study reports on modification of conventional welding materials with titanium, boron and silicon to enhance weldability by reducing the solidus temperature and promoting the formation of low temperature eutectics. Melting behavior, weld microstructure, tensile and stress rupture strength are reported for several alloy compositions. Some examples of repairs of IGT and aero HPT blades using the materials and technologies are provided.

Numerical Analysis to Lead Free Solder/Intermetallic Interconnect With Application of Wiedemann-Franz-Lorenz Relation

2012 ◽  
Author(s):  
Yao Yao ◽  
Jared Fry ◽  
Morris Fine ◽  
Leon Keer
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Material Properties ◽  
Interfacial Crack ◽  
Electrical Current ◽  
Lead Free ◽  
Lead Free Solder ◽  
Electrical Conductivities ◽  
Free Solder

Due to the limitation of available experimental data for thermal conductivity of lead free solder and Intermetallic Compound (IMC) materials, the Wiedemann-Franz-Lorenz (WFL) relation is presented in this paper as a possible solution to predict thermal conductivity with known electrical conductivity. The method is based upon the fact that heat and electrical transport both involve the free electrons. The thermal and electrical conductivities of Cu, Ni, Sn, and different Sn rich lead free solder and IMC materials are studied by employing the WFL relation. Generally, the analysis to the experimental data shows that the WFL relation is obeyed in both solder alloy and IMC materials especially matches close to the relation for Sn, with a positive deviation from the theoretical Lorenz number. Thus, with the available electrical conductivity data, the thermal conductivity of solder and IMC materials can be obtained based on the proper WFL relation, vice versa. With the reduction of size of electronic devices and solder interconnects, it has been observed experimentally that solders fail by crack nucleation and propagation near the interface of IMC and bulk solder. A coupled thermal-electrical finite element analysis is performed to study the behavior of lead free solder/IMC interconnects under different electrical current densities. The joule heating, temperature concentration and electrical current concentration effects with a crack propagating near the interface of solder and IMC are investigated numerically. Solder and IMC material properties predicted using the WFL relation are adopted in the computational model. The effects of different thermal and electrical conductivities of solder and IMC materials on interfacial crack tip temperature are analyzed in the present study. By applying the WFL relation, the amount of experiments required to determine the material properties for different lead free solder/IMC interconnects can be significantly reduced, which can lead to pronounced saving of time and cost.

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