INTERNAL STRESS OF CHROME COATINGS ELECTRODEPOSITED FROM SOLUTIONS OF CHROMIUM (III) SALTS

2019 ◽  
Vol 62 (12) ◽  
pp. 33-38 ◽  
Author(s):  
Evgeniy G. Vinokurov
Keyword(s):  
Experimental Data ◽  
Tensile Stress ◽  
Internal Stress ◽  
Compressive Stress ◽  
Current Density ◽  
Plate Thickness ◽  
Similar Data ◽  
Thin Coatings ◽  
The Difference

Experimental data on internal stress in chromium coatings electrodeposited from Cr(III)-solutions have been obtained. Tensile stress 250-300 MPa is observed in thin coatings with thickness was below 1-3 μm. The internal stress is practically independent on current density and pH of the solution. A reduction in the plate thickness corresponding to σ=0 is observed, when pH has changed from 1.2 to 1.6 and current density from 30 to 35 A/dm2 at higher values of pH and current density compressive stress is observed and increases the difference in the stress values at greater thicknesses of the coatings: ((– 10) - (– 50) MPa). These results have been compared with similar data for the coatings deposited from Cr(VI) solutions including the effects of the non-metal inclusions in the coatings (for Cr(III)-bath H – 10.5 - 13 at. % (26 - 32 ml H2 / g Cr), O – 0.06-0.6 at. %, С – 0.04-7.8 at. %; for Cr(VI)-bath H – 1.8 at. %, O – 1.2 at. %, С – 0 at. %)). Compressive stress, related with the inclusions (including carbides) is the major cause, limiting the possibility to improve the characteristics of chromium coatings and to deposit coatings of the quality comparable to that of chrome plated from Cr(VI) baths.

Effect of internal stress on elemental diffusion and crystallization of electroless Ni–Cu–P deposit on Al

2003 ◽  
Vol 18 (9) ◽  
pp. 2221-2227 ◽  
Author(s):  
Jen-Che Hsu ◽  
Kwang-Lung Lin
Keyword(s):  
Tensile Stress ◽  
Diffusion Couple ◽  
Internal Stress ◽  
Compressive Stress ◽  
Crystallization Behavior ◽  
Amorphous Structure ◽  
Diffusion Behavior ◽  
Elemental Diffusion ◽  
Plating Solution ◽  
Electroless Ni

The type and magnitude of stress in electroless Ni–Cu–P deposits on Al were manipulated by controlling the concentration of saccharin in the plating solution. Tensile, zero, and compressive stress of the electroless Ni–Cu–P deposits was obtained with 0, 8, and 10 g/l saccharin for studying the effect of stress on the diffusion and crystallization behavior of the deposit. The effect of stress on the diffusion behavior of Cu, Ni, and Al elements during annealing was investigated. Interdiffusion between Al and Ni in an amorphous Ni–Cu–P/crystal Al diffusion couple is abated by the effects of amorphous structure, atomic affinity, and backstress. Therefore, the effect of stress on diffusion is manifested by Cu elemental diffusion. The tensile stress promotes the formation of Ni3P and the diffusion of Cu into the substrate.

Study on Internal Stress in Micro-Electroformed Layer

2015 ◽  
Vol 645-646 ◽  
pp. 178-183 ◽  
Author(s):  
Li Qun Du ◽  
Zhi Cheng Tan ◽  
Chang Song ◽  
Zhong Zhao ◽  
Qing Feng Li ◽  
...  
Keyword(s):  
Internal Stress ◽  
Compressive Stress ◽  
Current Density ◽  
Stress Reduction ◽  
Research Work ◽  
Ultrasonic Power ◽  
Free Solution ◽  
And Performance ◽  
Additive Solution ◽  
High Internal Stress

Micro electroforming technology is widely used in fabrication of multilayer or moveable metal micro devices. The fabrication of these devices is usually suffered from high internal stress in micro-electroformed layers which seriously restricts the application and development of micro electroforming technology. Therefore, to control the internal stress is very important for improving the quality and performance of micro-electroformed layer. However, published studies on internal stress in the electroforming layer were mostly based on additive-free solution. According to additive solution, the effect of ultrasonic and current density on compressive stress occurring in the electroforming layer is investigated in this paper. The results indicate that the compressive stress keeps increasing with current density within range from 0.2 to 2 A/dm2. Meanwhile, the compressive stress in ultrasonic solution decreases by 73.4 MPa averagely comparing to that in ultrasonic-free solution, and the compressive stress also keeps decreasing with the ultrasonic power which gets the lowest value at 200W. Moreover, the mechanisms of additive-induced compressive stress and ultrasonic relieving compressive stress are discussed. This research work will complement the ultrasonic-stress reduction theory and may contribute to the development of micro electroforming technology.

Internal Stress Generation in Rattan Canes

IAWA Journal ◽  
1999 ◽  
Vol 20 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Willie Abasolo ◽  
Masato Yoshida ◽  
Hiroyuki Yamamoto ◽  
Takashi Okuyama
Keyword(s):  
Tensile Stress ◽  
Internal Stress ◽  
Compressive Stress ◽  
Compression Wood ◽  
Lignin Content ◽  
Stress Generation ◽  
Tensile Stresses ◽  
Stress Development ◽  
The Core ◽  
Compressive Stresses

Internal stress development was investigated in rattan canes (Calamus merrillii Becc.) following the procedures used in trees. Measurements showed that longitudinal compressive stresses existed at the periphery while longitudinal tensile stresses existed at the core. Such stresses originated from the fibers. Fiber MFA was observed to be beyond 20" and the lignin content was above 30%. Considering its similarities to compression wood tracheids, it was assumed that the rattan fibers generated longitudinal compressive stress. The amount of stress varied from base to top and from periphery to core because of the variation in the proportion of fibers along these points. This is why the longitudinal compressive stress that was generated at the base was higher than at the top and high longitudinal compressive stress was developed at the periphery. As a response to this high peripheral stress, longitudinal tensile stress was induced at the core.

Instability Analysis of the Bipolar Plate for Welding Fuel Cell

2012 ◽  
Vol 152-154 ◽  
pp. 568-573
Author(s):  
Yu Xin Yao ◽  
Chun Yuan Shi
Keyword(s):  
Fuel Cell ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Thin Plate ◽  
Bipolar Plate ◽  
Maximum Compressive Stress ◽  
Heating And Cooling ◽  
Instability Theory ◽  
The Difference

The instability of the bipolar plate for welding fuel cell was analyzed taking the bipolar plate as thin plate. The minimum compressive stress is calculated based on thin plate instability theory caused by longitudinal compressive stress. The simplified thermal stress distribution function is determined using the analytical solution of the plane heat conduction equation. The maximum compressive stress is determined through the analysis of the longitudinal stress distribution of the cross section passing through the solder point during heating and cooling process. The results are used to obtain the pre-tensile stress controlling the instability of the bipolar plate for welding fuel cell, and the minimum pre-tensile stress is the difference between the maximum compressive stress and the minimum compressive stress as the thin plate loses instability.

scholarly journals Fatigue Resistance and Failure Behavior of Penetration and Non-Penetration Laser Welded Lap Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xiangzhong Guo ◽  
Wei Liu ◽  
Xiqing Li ◽  
Haowen Shi ◽  
Zhikun Song
Keyword(s):  
Fatigue Resistance ◽  
Failure Modes ◽  
Plate Thickness ◽  
High Stress ◽  
Lap Joints ◽  
Failure Behavior ◽  
Passenger Cars ◽  
Plate Fracture ◽  
The Difference ◽  
Railway Passenger

AbstractPenetration and non-penetration lap laser welding is the joining method for assembling side facade panels of railway passenger cars, while their fatigue performances and the difference between them are not completely understood. In this study, the fatigue resistance and failure behavior of penetration 1.5+0.8-P and non-penetration 0.8+1.5-N laser welded lap joints prepared with 0.8 mm and 1.5 mm cold-rolled 301L plates were investigated. The weld beads showed a solidification microstructure of primary ferrite with good thermal cracking resistance, and their hardness was lower than that of the plates. The 1.5+0.8-P joint exhibited better fatigue resistance to low stress amplitudes, whereas the 0.8+1.5-N joint showed greater resistance to high stress amplitudes. The failure modes of 0.8+1.5-N and 1.5+0.8-P joints were 1.5 mm and 0.8 mm lower lap plate fracture, respectively, and the primary cracks were initiated at welding fusion lines on the lap surface. There were long plastic ribs on the penetration plate fracture, but not on the non-penetration plate fracture. The fatigue resistance stresses in the crack initiation area of the penetration and non-penetration plates calculated based on the mean fatigue limits are 408 MPa and 326 MPa, respectively, which can be used as reference stress for the fatigue design of the laser welded structures. The main reason for the difference in fatigue performance between the two laser welded joints was that the asymmetrical heating in the non-penetration plate thickness resulted in higher residual stress near the welding fusion line.

scholarly journals Epistemic values of quantity and variety of evidence in biological mechanism research

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Yin Chung Au
Keyword(s):  
Experimental Data ◽  
Causal Inference ◽  
Case Studies ◽  
Biological Mechanism ◽  
Data Generation ◽  
Extended Version ◽  
Epistemic Values ◽  
Difference Making ◽  
Mechanism Research ◽  
The Difference

AbstractThis paper proposes an extended version of the interventionist account for causal inference in the practical context of biological mechanism research. This paper studies the details of biological mechanism researchers’ practices of assessing the evidential legitimacy of experimental data, arguing why quantity and variety are two important criteria for this assessment. Because of the nature of biological mechanism research, the epistemic values of these two criteria result from the independence both between the causation of data generation and the causation in question and between different interventions, not techniques. The former independence ensures that the interventions in the causation in question are not affected by the causation that is responsible for data generation. The latter independence ensures the reliability of the final mechanisms not only in the empirical but also the formal aspects. This paper first explores how the researchers use quantity to check the effectiveness of interventions, where they at the same time determine the validity of the difference-making revealed by the results of interventions. Then, this paper draws a distinction between experimental interventions and experimental techniques, so that the reliability of mechanisms, as supported by the variety of evidence, can be safely ensured in the probabilistic sense. The latter process is where the researchers establish evidence of the mechanisms connecting the events of interest. By using case studies, this paper proposes to use ‘intervention’ as the fruitful connecting point of literature between evidence and mechanisms.

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

Dose-window dependence on Si crystal orientation in separation by implanted oxygen substrate formation

2004 ◽  
Vol 19 (12) ◽  
pp. 3607-3613 ◽  
Author(s):  
H. Iikawa ◽  
M. Nakao ◽  
K. Izumi
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Crystal Orientation ◽  
Oxygen Ion ◽  
The Difference ◽  
First Time ◽  
Good Agreement

Separation by implemented oxygen (SIMOX)(111) substrates have been formed by oxygen-ion (16O+) implantation into Si(111), showing that a so-called “dose-window” at 16O+-implantation into Si differs from Si(100) to Si(111). In SIMOX(100), an oxygen dose of 4 × 1017/cm2 into Si(100) is widely recognized as the dose-window when the acceleration energy is 180 keV. For the first time, our work shows that an oxygen dose of 5 × 1017/cm2 into Si(111) is the dose-window for the formation of SIMOX(111) substrates when the acceleration energy is 180 keV. The difference between dose-windows is caused by anisotropy of the crystal orientation during growth of the faceted buried SiO2. We also numerically analyzed the data at different oxidation velocities for each facet of the polyhedral SiO2 islands. Numerical analysis results show good agreement with the experimental data.

The Tensile Property of the SPF/Cotton Blended Yarn

2011 ◽  
Vol 321 ◽  
pp. 192-195
Author(s):  
Qing Bin Yang ◽  
Xiao Yang
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Tensile Property ◽  
Cotton Fibers ◽  
Blended Yarn ◽  
The Difference ◽  
The Relationship

In order to analysis the relationship between the strength and elongation and the blended ratio of SPF/Cotton blended yarn, the strength and elongation of SPF /cotton blended yarn with different blended ratio were measured and compared with the simple model. The results indicated that For the SPF/cotton blended yarn, the difference between the experimental data and the model value is remarkable because of the high cohesion of the cotton fibers.

Experimental Study on the Relationship between Dislocation Density and Internal Stress in Micro Electroforming Layer

2015 ◽  
Vol 645-646 ◽  
pp. 405-410 ◽  
Author(s):  
Chang Song ◽  
Li Qun Du ◽  
Tong Yang ◽  
Lei Luo ◽  
You Sheng Tao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dislocation Density ◽  
Internal Stress ◽  
Compressive Stress ◽  
Stress Relief ◽  
Ultrasonic Power ◽  
Pile Up ◽  
Ultrasonic Stress Relief ◽  
The Relationship ◽  
Dislocation Density Increase

In the micro electroforming process, the existence of electroforming layer defects caused by macro internal stress seriously limits the application and development of the micro electroforming technology. Currently, some studies have shown that ultrasonic can reduce the internal stress. But the formation process of the internal stress and the mechanism of ultrasonic stress relief in micro electroforming layer are still unclear now. In this paper, the relationship between dislocation density and internal stress under ultrasonic was studied. The results show that the ultrasonic can make the dislocation density increase and the compressive stress decrease. When the ultrasonic power is 200W, the dislocation density and the compressive stress culminate 3.8×10-15m-2 and-144.4MPa, respectively. The ultrasonic can excite the movement of dislocation proliferation, pile-up and opening, which leads to a micro plastic deformation in the crystal, and thereby releases the internal stress.

Sign in / Sign up

Export Citation Format

Share Document