Pressureless sinter joining of bare Cu substrates under forming gas atmosphere by surface-oxidized submicron Cu particles

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

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Investigations of the corrosion activity of the KAlCl4 melts by the methods of physicochemical analysis

Practice of Anticorrosive Protection ◽

10.31615/j.corros.prot.2019.94.4-7 ◽

2019 ◽

Vol 24 (4) ◽

pp. 59-66

Author(s):

E.S. Filatov

Keyword(s):

Water Vapor ◽

Hydrochloric Acid ◽

Input Data ◽

Corrosion Potential ◽

Physicochemical Analysis ◽

Metal Alloys ◽

Corrosion Activity ◽

Protection Efficiency ◽

Gas Atmosphere ◽

Metal Aluminum

Corrosion behavior of metal alloys in a melt of potassium chloroaluminate (KAlCl4) was investigated. Metal aluminum was used as a protector for protection against continuous frontal corrosion. The equilibrium potentials of aluminum and the corrosion potential of the alloys were measured. The data were obtained to evaluate the corrosion ability of the system of molten salt of potassium chloroaluminate - gas (argon) by measuring the redox potential of the specified environment depending on the composition of the gas atmosphere above it, i.e. from impurities of water vapor, hydrochloric acid, oxygen and other, for example, carbonaceous gases. The calculations of the protection efficiency using the potential difference between the metal aluminum and the protected material were performed. The regularities of changes in the equilibrium potentials of aluminum from the temperature and concentration were established as the fundamental data for possible use at determining the composition ratio of potassium chlorides and aluminum in potassium chloroaluminate as input data for the development of a sensor of composition of chloroaluminate potassium.

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Extraordinary dendrite-free Li deposition on highly uniform facet wrinkled Cu substrates in carbonate electrolytes

Nano Energy ◽

10.1016/j.nanoen.2020.105736 ◽

2020 ◽

pp. 105736

Author(s):

Ju Ye Kim ◽

Oh B. Chae ◽

Mihye Wu ◽

Eunsoo Lim ◽

Gukbo Kim ◽

...

Keyword(s):

Cu Substrates ◽

Highly Uniform

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Pressureless and low-temperature sinter-joining on bare Si, SiC and GaN by a Ag flake paste

Scripta Materialia ◽

10.1016/j.scriptamat.2021.113833 ◽

2021 ◽

Vol 198 ◽

pp. 113833

Author(s):

Zheng Zhang ◽

Chuantong Chen ◽

Aiji Suetake ◽

Ming-Chun Hsieh ◽

Aya Iwaki ◽

...

Keyword(s):

Low Temperature ◽

Temperature Sinter ◽

Sinter Joining

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Effect of Plating Current Density on the Ball-On-Disc Wear of Sn-Plated Ni Coatings on Cu Foils

Coatings ◽

10.3390/coatings11010056 ◽

2021 ◽

Vol 11 (1) ◽

pp. 56

Author(s):

Ashutosh Sharma ◽

Byungmin Ahn

Keyword(s):

Current Density ◽

Wear Loss ◽

Wear Properties ◽

Friction Behavior ◽

Track Geometry ◽

Cu Substrates ◽

Current Densities ◽

The Impact ◽

Sliding Distance ◽

Ball On Disc

Metallic and alloyed coatings are used widely in several decorative and technology-based applications. In this work, we selected Sn coatings plated on Cu substrates for joining applications. We employed two different plating baths for the fabrication of Sn and Ni coatings: acidic stannous sulfate for Sn and Watts bath for Ni layer. The plating current densities were varied from 100–500 mA/cm2. Further, the wear and friction behavior of the coatings were studied using a ball-on-disc apparatus under dry sliding conditions. The impact of current density was studied on the morphology, wear, and coefficient of friction (COF) of the resultant coatings. The wear experiments were done at various loads from 2–10 N. The sliding distance was fixed to 7 m. The wear loss was quantified in terms of the volume of the track geometry (width and depth of the tracks). The results indicate that current density has an important role in tailoring the composition and morphology of coatings, which affects the wear properties. At higher loads (8–10 N), Sn coatings on Ni/Cu had higher volume loss with a stable COF due to a mixed adhesive and oxidative type of wear mechanism.

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Pilot Test of Olefin Synthesis from Dimethyl Ether in a Synthesis Gas Atmosphere

Industrial & Engineering Chemistry Research ◽

10.1021/acs.iecr.1c00363 ◽

2021 ◽

Author(s):

Maria V. Magomedova ◽

Mikhail I. Afokin ◽

Anastasiya V. Starozhitskaya ◽

Ekaterina G. Galanova

Keyword(s):

Dimethyl Ether ◽

Synthesis Gas ◽

Pilot Test ◽

Olefin Synthesis ◽

Gas Atmosphere

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Growth of Salmonella typhimurium and Mesophilic Organisms on Beef Steaks as Influenced by Type of Packaging1,2

Journal of Food Protection ◽

10.4315/0362-028x-45.3.263 ◽

1982 ◽

Vol 45 (3) ◽

pp. 263-267 ◽

Cited By ~ 19

Author(s):

L. S. LUITEN ◽

J. A. MARCHELLO ◽

F. D. DRYDEN

Keyword(s):

Treatment Group ◽

Salmonella Typhimurium ◽

Vacuum Packaging ◽

Gas Atmosphere ◽

Beef Steaks ◽

Retail Meat

Two trials, each utilizing 72 samples of fresh beef loin steak, were done to determine the effects of various packing systems upon growth of Salmonella typhimurium. Samples were inoculated with 105 cells/cm2 of the organism and randomly assigned to four packaging treatments: (1) overwrapping in oxygen-permeable film; (2) vacuum packaging; (3) packaging in barrier bags flushed with a 60% CO2: 40% O2 gas atmosphere then evacuated and sealed; and (4) packaging in barrier bags filled with a 60% CO2: 40% O2 gas atmosphere. Twelve steak samples were inoculated with S. typhimurium and 6 were uninoculated and served as a control in each treatment group. Samples were displayed in retail meat cases at 10 C for 3, 6 or 9 days, when they were evaluated for shrinkage and numbers of mesophilic organisms and S. typhimurium. Percent shrinkage was not affected (P>0.05) by packaging treatment. Counts of mesophilic organisms were similar (P>0.05) for vacuum- and gas-treated steaks, which were significantly lower (P<0.05) than counts from film overwrapped samples. Numbers of S. typhimurium increased significantly (P<0.05) during storage on samples wrapped with oxygen permeable film but remained low and fairly constant for vacuum- or gas-treated steaks. After 9 days of display, the film overwrapped steaks had greater (P<0.05) numbers of S. typhimurium than those of other treatments, whereas steaks held within the 60% CO2: 40% O2 gas atmosphere had lowest numbers overall.

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