scholarly journals Research of Joining Brittle Nonmetallic Materials with an Active Solder

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Roman Koleňák ◽  
Michal Prach
Keyword(s):  
Shear Strength ◽  
High Purity ◽  
Bond Formation ◽  
Wetting Angle ◽  
Soldering Temperature ◽  
Average Value ◽  
Soldering Time ◽  
Diffusion Character

This paper deals with soldering high-purity brittle, nonmetallic materials such as SiO2, Si, and C (graphite). However, these materials exert poor wettability when using tin solder. Therefore, to reduce the wetting angle, an Sn solder alloyed with active Ti element was used. At a soldering temperature of 860°C and 15 min soldering time, the wetting angle on SiO2ceramics was 30°, on silicon 42°, and on graphite 52°. All these wetting angles are below 90° and are acceptable for soldering. It has been shown that the bond in all joined materials (SiO2, Si, and C) was of a diffusion character. New intermetallic products were formed on the boundary with nonmetal, thus allowing bond formation. The shear strength of SiO2ceramics attained an average value of 17 MPa.

ALCOA 1XXX SERIES

Alloy Digest ◽  
2005 ◽  
Vol 54 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Purity ◽  
High Conductivity ◽  
Good Corrosion Resistance

Abstract Aluminum 1xxx series alloys are nonhardenable by heat treatment. They have high purity, high conductivity, and good corrosion resistance and are easily formed. This datasheet provides information on composition, physical properties, tensile properties, and shear strength. It also includes information on corrosion resistance as well as forming, machining, joining, and surface treatment. Filing Code: AL-395. Producer or source: Alcoa Engineered Products.

The quality of the wood bonding depending on the method of applying the selected thermoplastic biopolymers

2021 ◽  
Vol 116 ◽  
pp. 78-85
Author(s):  
Aneta Gumowska ◽  
Grzegorz Kowaluk
Keyword(s):  
Shear Strength ◽  
Solid Wood ◽  
Average Value ◽  
Wood Bonding ◽  
Research Show

The quality of the wood bonding depending on the method of applying the selected thermoplastic biopolymers. The aim of the research was to determine the effect of the method of applying the biopolymer on the surface of bonding solid wood elements on the quality of the obtained adhesive connection. The results of conducted mechanical research show that the highest average value of shear strength was observed for birch lamellas bonded with PLA, both with the first and second method of application. In case of estimating the quality of the bonding of wooden elements, better results were achieved for PLA and the second method of application the "green" adhesive.

scholarly journals INFLUENCE OF MICROBIAL CARBONATE MINERALIZATION ON HYDROPHOBICITY OF A CEMENT STONE SURFACE

2020 ◽  
pp. 19-25
Author(s):  
U. Duhanina ◽  
V. Strokova ◽  
D. Balickiy
Keyword(s):  
Calcium Carbonate ◽  
Experimental Studies ◽  
Wetting Angle ◽  
Cement Stone ◽  
Stone Surface ◽  
Lysinibacillus Sphaericus ◽  
Average Value ◽  
Microbial Carbonate ◽  
Contact Wetting Angle ◽  
The Relationship

The effect of microbial carbonate mineralization on increasing the hydrophobicity of the cement stone surface is theoretically justified and experimentally confirmed. Based on experimental studies and analysis of literature data, the main stages of microbial-induced sedimentation of calcium carbonate on the surface of a cement stone are formulated. Changes in the morphology of the cement stone surface due to crystalline new formations formed during biomineralization in the postgenetic period are described. It is shown that biocolmatation of the interstitial space of a cement stone by crystalline new formations leads to an increase in hydrophobicity, as evidenced by an increase in the contact wetting angle. The relationship between the change in the concentration of calcium in neoplasms and the average value of the contact wetting angle on the surface of the cement stone from the type of bacterial culture is established. According to chemical and morphological analysis of bioinduction tumors on the surface of samples and also evaluation of changes of the contact angle compared to the original index for cement, bacterial cultures are ranked in order to increase the efficiency of use for sedimentation of calcium carbonate with their participation, as well as increase of cement materials hydrophobicity in the following sequence: Sporosarcina pasteurii  Bacillus megaterium  Lysinibacillus sphaericus  Bacillus pumilus.

Determination of the molar absorptivity of NADH.

1976 ◽  
Vol 22 (2) ◽  
pp. 141-150 ◽  
Author(s):  
R B McComb ◽  
L W Bond ◽  
R W Burnett ◽  
R C Keech ◽  
G N Bowers
Keyword(s):  
Systematic Error ◽  
Standard Error ◽  
High Purity ◽  
Molar Absorptivity ◽  
Average Value ◽  
Effects Of Ph ◽  
The Mean ◽  
Ph Buffer ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract The molar absorptivity of NADH at 340 nm has been determined by an indirect procedure in which high-purity glucose is phosphorylated by ATP in the presence of hexokinase, coupled to oxidation of the glucose-6-phosphate by NAD+ in the presence of glucose-6-phosphate dehydrogenase. The average value from 85 independent determinations is 6317 liter mol-1 cm-1 at 25 degrees C and pH 7.8. The overall uncertainty is -4.0 to +5.5 ppt (6292 to 6352 liter mol-1 cm-1), based on a standard error of the mean of 0.48 ppt and an estimate of systematic error of -2.6 to +4.1 ppt. Effects of pH, buffer, and temperature on the molar absorptivity are also reported.

Investigation of Flux-Less Soldering of Metal Matrix Composite and Ceramics by Use of Zn Solder

2018 ◽  
Vol 759 ◽  
pp. 29-34
Author(s):  
Roman Koleňák ◽  
Igor Kostolný
Keyword(s):  
Metal Matrix Composite ◽  
Metal Matrix ◽  
Ceramic Composite ◽  
Bond Formation ◽  
Hot Plate ◽  
Soldering Temperature ◽  
Metal Ceramic ◽  
Transient Zone ◽  
Microstructural Studies ◽  
Al Matrix

The work was dealing with direct soldering of Al2O3 ceramics and a metal/ceramic composite (MMC) with Al matrix. The joints were fabricated by application of flux-less process by use of a hot plate at the assistance of ultrasound with frequency of 40 kHz. The experiments were performed by use of Zn6Al6Ag solder. Wetting was attained on both substrates. The joints of a good quality were fabricated. The soldering temperature was 420 °C. The microstructural studies of interface have revealed a transient zone of Al dissolving on the side of MMC and formation of Zn oxides on the side of ceramics, which were responsible for bond formation.

Crack Reduction in Tabbing and Stringing Processes for Solar Cells

2018 ◽  
Vol 777 ◽  
pp. 126-131 ◽  
Author(s):  
Atcharapha Kongwiriyaphaisan ◽  
Viboon Tangwarodomnukun
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Adhesion Force ◽  
Substrate Surface ◽  
Production Yield ◽  
Silicon Solar Cells ◽  
Mechanical Loads ◽  
Soldering Temperature ◽  
Soldering Time ◽  
Cell Manufacturing

Wafer cracking is considered to be an important loss in solar cell manufacturing as it crucially affects the production yield as well as the efficiency of solar cells fabricated. There is a certain chance of cracking in wafer when the substrate undergoes some thermal and/or mechanical loads during its fabrication. This research therefore aims to decrease the solar cells cracking in tabbing and stringing processes as the two processes are responsible for a great number of cracks in the substrate. A set of experiments was performed in this study, where soldering temperature and time were tested and the amount of cracks in solar cells was quantified. The findings showed that the use of 185°C soldering temperature with the soldering time of 1,200 ms can reduce the number of cracks in the tabbing and stringing of silicon solar cells. With this setup, the adhesion force between tabbing ribbons and substrate surface can also be promoted, thus preventing the delamination problem in the cell panels.

Void Formation and Bond Strength Investigated for Wafer-Level Cu-Sn Solid-Liquid Interdiffusion (SLID) Bonding

2014 ◽  
Vol 11 (1) ◽  
pp. 1-6
Author(s):  
Astrid-Sofie B. Vardøy ◽  
H. J. van de Wiel ◽  
Stian Martinsen ◽  
Greg R. Hayes ◽  
Hartmut R. Fischer ◽  
...  
Keyword(s):  
Shear Strength ◽  
Process Parameters ◽  
Storage Time ◽  
Void Formation ◽  
Wafer Level ◽  
Lower Range ◽  
Thermal Budget ◽  
Average Value ◽  
Application Analysis ◽  
Solid Liquid

Hermetic wafer-level Cu-Sn solid-liquid interdiffusion (SLID) bonding was investigated to explore the sensitivity of selected process parameters with regard to voiding and possible reduction of strength. Little or no variation was observed in the void density as a result of modifying the plated Sn thickness, the storage time between plating and bonding, the bonding tool pressure, or the thermal budget during bonding. All shear tested samples showed excellent shear strength, with an average value within 110–164 MPa. Some statistically significant differences in shear strength were found due to the variations of the process parameters. However, the differences were too small to be critical for the application. Analysis of fracture surfaces showed that the shear strengths in the lower range corresponded to fracture between the adhesion layer (TiW) and the silicon cap, while shear strengths in the higher range corresponded to fracture in the Cu3Sn formed during the bonding. The results indicate that the investigated bonding process is robust with regard to the studied process parameters.

Joining Active Metals with Al2O3 by Use of Solders

2013 ◽  
Vol 664 ◽  
pp. 667-671
Author(s):  
Roman Koleňák ◽  
Michal Prach
Keyword(s):  
Active Element ◽  
Metallic Substrate ◽  
Soldering Temperature ◽  
Diffusion Bond ◽  
Soldering Process ◽  
Soldering Time ◽  
Temperature Capability

The work deals with joining active metals as Ti, Zr and Hf with Al2O3ceramics. The solubility of these active metals in selected Sn and In based solders was studied at a selected soldering temperature. Capability of active metals to wet Al2O3ceramics and to form a diffusion bind was ascertained. Soldering was performed with Sn, Sn5Ag, In and In30Sn solders, which were enriched by an active element from metallic substrate of the joint in soldering process. Soldering temperature in vacuum varied from 770 to 870 °C and soldering time was selected from 8 to 20 min. It was found out that the most suitable metal for active solders is Ti, because it is dissolved in Sn solder already at temperature 780 °C. Wetting of ceramic Al2O3substrate and formation of a diffusion bond was achieved already at temperature 830 °C/8 min. Diffusion bond with Zr was formed just at temperature 870 °C/20 min. and it was impossible to form a diffusion bond with Hf.

Determination of Shear Stress in Pull out Tests in Laminated Bamboo Guadua angustifolia

2015 ◽  
Vol 668 ◽  
pp. 17-22 ◽  
Author(s):  
Caori Patricia Takeuchi ◽  
Martin Estrada ◽  
Dorian Luis Linero
Keyword(s):  
Shear Strength ◽  
Shear Stresses ◽  
Average Value ◽  
Pull Out ◽  
Laminated Bamboo ◽  
Tension Tests ◽  
Cross Section Area ◽  
Section Area ◽  
The Common

Specimens of laminated bamboo Guadua angustifolia do not usually fail due to fiber breakage when submitted to shear stresses. The common failure mechanism in that case is slippage in the fiber-matrix interface, accompanied by degradation of the lignin matrix (parenchyma). In this study the shear strength of laminated bamboo Guadua angustifolia specimens was determined by tension tests reducing the cross section area. The perimeter of the slipped area was determined using digital image processing. Shear stresses were calculated taking into account the load and slipped area in specimens of two different groups, depending on the orientation of the laminated boards. It was found that the average value of the shear strength on pull out tests were 2.9 MPa, which is a mechanical property of the material that is useful, for example, in the analysis of the behavior of the joints, and analysis of the fracture process.

scholarly journals Study the radioactive concentration for soil samples contaminated with depleted uranium in Al-Nahrawan site at Baghdad governorate using high purity germanium detector

2021 ◽  
Vol 2114 (1) ◽  
pp. 012011
Author(s):  
B. H. Essa ◽  
M.A. Siyah ◽  
A.H. Al-Mashhadani
Keyword(s):  
High Purity ◽  
Germanium Detector ◽  
Soil Samples ◽  
Depleted Uranium ◽  
Average Value ◽  
High Purity Germanium ◽  
Gamma Analysis ◽  
Radioactive Concentration ◽  
Different Depths ◽  
K Concentration

Abstract This study is investigating the radioactivity in soil samples at the Al-Nahrawan site. The radiation survey appears there are 3000 square meters area are contaminated with DU in AL-Nahrawan site identified using Geiger–Müller (GM) for radiation survey and gamma spectrometry for 52 soil samples analysis taken from AL-Nahrawan site at different depths (0-70) cm and different locations. The results of gamma analysis using high-purity germanium show that the ratio between 235U/238U is less than 0.00720 (neutral ratio), and it has different values from 0.002-0.00588, and the average value of radioactive nuclides concentration for (238U, 235U and 40K) are (76019.61, 259.55 and 147.5) Bq/kg respectively, these values are higher than the (BG) radioactive concentration levels in Iraq for (238U and 235U) isotopes, and the analysis of 40K concentration appeared in the acceptable limits. The health effects of depleted uranium in the human body it is exposed to many health troubles through the entry of uranium oxide particles.

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