scholarly journals Properties of Ag-SnO2 Contact Materials for Low-Voltage Electrical Appliances with Different Doped Particle Sizes

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Haitao Wang ◽  
Mei Zhang ◽  
Menglin Yang
Keyword(s):  
Particle Size ◽  
Low Voltage ◽  
Electrical Contact ◽  
Powder Metallurgy Method ◽  
Particle Sizes ◽  
Contact Materials ◽  
Additive Particle ◽  
Surface Morphologies ◽  
The Relationship ◽  
Scanning Electron

In this paper, the relationship between additive particle size and properties of Ag-SnO2 contact materials was studied. La2O3 and Fe2O3 were selected as additives for contact materials, and the proportion of additives were determined by wettability experiment results; Ag-SnO2 contact materials were successfully fabricated by the powder metallurgy method, and the physical and electrical contact properties of Ag-SnO2 contact materials with five additive particle sizes were investigated. The results show the influence of additives on the properties of Ag-SnO2 contact materials are disparate, the contact resistance and arc energy are smaller and more stable when the additive particle size is about 500 nm. For further proving this conclusion, the arc-eroded surface morphologies of the doped AgSnO2 contact materials were investigated by scanning electron microscopy (SEM), which indicated that the properties of two kinds of Ag-SnO2 contact materials could be improved significantly by selecting appropriate additive particle size.

Production of quicklime from Ashaka limestone through calcination process

2021 ◽  
Vol 1 (2) ◽  
pp. 041-048
Author(s):  
Benson Chinweuba Udeh
Keyword(s):  
Particle Size ◽  
Critical Value ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Particle Sizes ◽  
Calcination Process ◽  
Process Effects ◽  
Effects Of Temperature ◽  
The Difference ◽  
The Relationship

This study is on the production of quicklime from Ashaka limestone through calcination process. Effects of temperature, particle size and time on quicklime yield were determined. The experiment was carried out at temperatures of 800, 900, 1000, 1100 and 1200 0C, particle sizes of 80mm, 90mm, 100mm, 300mm and 425mm and times of 0.5hr, 1hr, 2hrs, 3hrs and 4hrs. Analyses of the results showed that quicklime was successfully produced from Ashaka limestone through the calcination process. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Recorded model F-value of 134.35 implies that the model is significant. The predicted R² of 0.9597 is in reasonable agreement with the adjusted R² of 0.9844; the difference is less than the critical value of 0.2. Optimum yield of 73.48% was obtained at optima operating conditions; temperature of 1000 0C, particle size of 90 µm and time of 3 hrs.

Properties of doped Ag–SnO2 electrical contact materials with different SnO2 particle sizes

2018 ◽  
Vol 6 (1) ◽  
pp. 016558 ◽  
Author(s):  
Wang Haitao ◽  
Zhang Mei ◽  
Yang Menglin ◽  
Wang Jingqin ◽  
Zhu Yancai
Keyword(s):  
Electrical Contact ◽  
Particle Sizes ◽  
Contact Materials ◽  
Sno2 Particle ◽  
Electrical Contact Materials

scholarly journals Microstructure refinement and physical properties of Ag-SnO2 based contact materials prepared by high-energy ball milling

2013 ◽  
Vol 45 (2) ◽  
pp. 173-180 ◽  
Author(s):  
V. Cosovic ◽  
M. Pavlovic ◽  
A. Cosovic ◽  
P. Vulic ◽  
M. Premovic ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Physical Properties ◽  
Ball Milling ◽  
Electrical Contact ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Powder Metallurgy Method ◽  
Contact Materials ◽  
Energy Ball ◽  
Electrical Contact Materials

High energy ball milling was used in order to improve dispersion of metal oxide in Ag-SnO2 electrical contact materials. The processed Ag-SnO2 (92:8) and Ag-SnO2In2O3 (87.8:9.30:2.9) powder mixtures were subsequently consolidated to bulk solid pieces by conventional powder metallurgy method. The characterization of the prepared samples included microstructural analysis by XRD and SEM, as well as measurements of physical properties such as density, hardness and electrical conductivity. The results of X-Ray analysis point to reduction of crystallite size after milling of about ten times. Microstructures of sintered Ag-SnO2 and Ag-SnO2 In2O3 materials display very fine dispersion of the oxide components in silver matrix. Somewhat higher uniformity was obtained for Ag-SnO2 In2O3 material which was illustrated by results of SEM analysis and more consistent microhardness values. The obtained values of studied physical properties were found to be in accordance with observed higher dispersion of metal oxide particles and comparable to properties of commercial electrical contact materials of this type.

On the Lapping Mechanism of Optical Fiber End-Surfaces Using Fixed Diamond Abrasive Films

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
JiAn Duan ◽  
DeFu Liu
Keyword(s):  
Particle Size ◽  
Optical Fiber ◽  
Material Removal ◽  
Abrasive Particle ◽  
Particle Sizes ◽  
Material Removal Mechanisms ◽  
Ductile Mode ◽  
Deformed Layer ◽  
Diamond Abrasive ◽  
Scanning Electron

The purpose of this paper is to reveal material removal mechanisms of optical fiber end-surface in lapping processes. The lapping process experiments are conducted using fixed diamond abrasive lapping films with various particle sizes of 6 μm, 3 μm, 1 μm, and 0.5 μm. The micrographs of the optical fiber end-surfaces are observed using a scanning electron microscope. The experimental results show that there exist three material removal modes in the lapping processes: brittle fracture mode, semibrittle and semiductile mode, and ductile mode. These modes are mainly controlled by abrasive particle size, and there appears a brittle-ductile transition’s critical point when lapping films with a particle size of 3 μm are used to lap optical fiber end-surfaces. An interpretation is proposed for the formation mechanism of the plastic deformed layer on the optical fiber end-surfaces.

The Application of the Wettability of Liquid-Solid in the Manufacture of High and Low Voltage Contacts

2011 ◽  
Vol 66-68 ◽  
pp. 2122-2129
Author(s):  
Shi Jun Chen ◽  
Pei Lin Duan
Keyword(s):  
Melting Point ◽  
Low Voltage ◽  
Electrical Contact ◽  
High Melting ◽  
High Melting Point ◽  
Contact Materials ◽  
Subsequent Processing

High or low voltage electrical contact is a kind of pseudo alloy which is mostly composed of a high melting point material and a low one. Liquid-solid wettability is widely used in the manufacture of contact materials and its subsequent processing. This article focuses on several solutions to the difficulties encountered during the process by liquid-solid wettability.

The Relationship Between Colliery-waste Particle Sizes and Plant Growth

1974 ◽  
Vol 1 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Christopher G. Down
Keyword(s):  
Particle Size ◽  
Plant Growth ◽  
Water Retention ◽  
Size Range ◽  
Growth Period ◽  
Dry Weight ◽  
Particle Sizes ◽  
Small Particles ◽  
The Relationship ◽  
Water Holding

Seed germination and dry-weight production in Lolium perenne were examined in relation to growth on 12-years-old colliery waste separated into seven size-fractions. The size-range was from more than 4,000 μ to less than 125 μ, and the growth period was up to 30 days. Germination percentages after 6 days generally increased with decreasing particle-size, as did dry-weight. Shoot : root ratios also showed an inverse relationship with particle size.After 30 days there was no distinction between dryweights on different particle sizes, except that on the largest fractions it had been found impossible to keep the plants alive. Problems of water-holding capacity are discussed, and the significance of soil particle-size in revegetation work is examined, it being concluded that an admixture of small particles is important for water retention and plant growth.

Effect of SnO2 Particle Size on Properties of Ag-SnO2 Electrical Contact Materials Prepared by the Reductive Precipitation Method

2014 ◽  
Vol 936 ◽  
pp. 459-463 ◽  
Author(s):  
Zhi Jie Lin ◽  
Xu Dong Sun ◽  
Shao Hong Liu ◽  
Jia Lin Chen ◽  
Ming Xie ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Citric Acid ◽  
Electrical Contact ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Composite Powders ◽  
Contact Materials ◽  
Electrical Contact Materials ◽  
Ag Particle

Performances of Ag-SnO2 electrical contact materials can be strongly affected by the microstructure. In this work, Ag-SnO2 composite powders were synthesized by chemical reductive precipitation method. During the precipitation process, Ag particle was deposited onto the surface of SnO2 particle with the assistance of citric acid. The microstructure and properties were analyzed for the prepared Ag-SnO2 electrical contact materials. Our research reveals that the particle size of SnO2 has significant influence on the morphology of the Ag-SnO2 composite powders, and therefore on the microstructure and physical properties of the electrical contact materials. With the decrease of particle size of SnO2, hardness of the Ag-SnO2 electrical contact materials increases, while electrical conductivity decreases.

scholarly journals The Influence of Starch Modification with Amylosucrase Treatment on Morphological Features

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1409
Author(s):  
Hyeyoung Lee ◽  
Inmyoung Park
Keyword(s):  
Particle Size ◽  
Cross Section ◽  
Resistant Starch ◽  
Flat Surface ◽  
Particle Sizes ◽  
Particle Size Analyzer ◽  
The Mean ◽  
Waxy Corn ◽  
Slowly Digestible Starch ◽  
Scanning Electron

Amylosucrase (AS) is a starch-modifying enzyme from Neisseria polysaccharea used to produce low-glycemic starches such as slowly digestible starch (SDS) and resistant starch (RS). The morphology of native, control, and AS-modified waxy corn starches (230 and 460 U) was examined using a particle size analyzer and field-emission scanning electron microscopy (FE-SEM). AS modification of the starch elongated the glucose and resulted in higher SDS and RS contents. The mean particle sizes of the control, 230 U-AS-, and 460 U-AS-treated starches were 56.6 µm, 128.0 µm, and 176.5 μm, respectively. The surface of the 460 U-AS-treated starch was entirely porous and coral-like, while the 230 U-AS-treated starch had a partial dense and flat surface which did not react with AS. FE-SEM of the granule cross section confirmed that the center contained a dense and flat region without any evidence of AS reaction to either of the AS-treated starches. It was assumed that the particle size and porous and sponge-like particle features might be related to the SDS and RS fractions.

Spatial and Temporal Patterns in Macrobenthic Stream Diversity

1976 ◽  
Vol 33 (6) ◽  
pp. 1261-1270 ◽  
Author(s):  
Brigitte G. E. de March
Keyword(s):  
Particle Size ◽  
Related Species ◽  
High Variability ◽  
Particle Sizes ◽  
Spatial And Temporal Patterns ◽  
Mean Particle Size ◽  
Faunal Assemblages ◽  
Number Of Species ◽  
Stream Community ◽  
The Relationship

The relationship between the characteristics of a stream community and sediments were studied for 1 yr in a small unpolluted river with a morainal substrate. Recognizable faunal assemblages were associated with silt or silt fill, sand or sand fill, and large boulders. The fauna in sediments of mean particle sizes coarser than sand but finer than boulders was characterized by a high variability due largely to temporal successions of morphologically related species. It was found that the number of species was directly proportional to mean particle size (in [Formula: see text] units) in spring when the sediments were well sorted, but the relationship broke down as the sediment interstices filled in. In late fall when the sediments were badly sorted, the number of species is perhaps more related to the sorting coefficient of the sediments. The relevance of these findings to studies of pollution is discussed.

Lime Brust of Sintering Bricks of Purple Sandy Shale: the Effect of Limestone Particle Size

2011 ◽  
Vol 250-253 ◽  
pp. 46-49
Author(s):  
Zhi Gang Feng ◽  
Zhen Ping Tang ◽  
Hui Juan Li
Keyword(s):  
Particle Size ◽  
Hunan Province ◽  
Particle Sizes ◽  
Sintering Process ◽  
Critical Content ◽  
Production Practice ◽  
Sandy Shale ◽  
Free Cao ◽  
The Relationship

Simulating current sintering process in local brickkilns, Hengyang region, Hunan Province, China, at 800°C, througt indoor sintering experiment on a series of brick samples of purple sandy shale, in which particle sizes of limestone are >-1Φ, >0Φ, >1Φ, >2Φ, >3Φ and >4Φ, respectively, it is concluded that the following: (1) Limestone granularity is a crucial factor affecting the quality of sintering bricks of purple sandy shale. Under different particle sizes, the critical content of limestone causing lime brust of sintering bricks is distinct, and lowers with the increasing in limestone granularity. (2) When limestone granularity is different, its impact way on the quality of sintering bricks is also distinct. The more coarse limestone granularity is, the more concentrative the swelling stress produced by the hydration of free CaO is, the more easily lime brust occurs. On the contrary, the more fine limestone granularity is, the more dispersive the swelling stress is, there is the more help to reduce or eliminate the occurrence of lime brust. (3) In view of the relationship between limestone granularity and the critical content of limestone giving rise to lime brust of sintering bricks, the production practice can be effectively guided.

Sign in / Sign up

Export Citation Format

Share Document