The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu n...The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu nanoparticles on the interface strength and failure behavior of the Ag-SnO_(2) contact materials are investigated by numerical simulations and experiments.Three-dimensional representative volume element(RVE)models for the Ag-SnO_(2) materials without and with Cu nanoparticles are established,and the cohesive zone model is used to simulate the interface debonding process.The results show that the stress−strain relationships and failure modes predicted by the simulation agree well with the experimental ones.The adhesion strengths of the Ag/SnO_(2) and Ag/Cu interfaces are respectively predicted to be 100 and 450 MPa through the inverse method.It is found that the stress concentration around the SnO_(2) phase is the primary reason for the interface debonding,which leads to the failure of Ag-SnO_(2) contact material.The addition of Cu particles not only improves the interface strength,but also effectively suppresses the initiation and propagation of cracks.The results have an reference value for improving the processability of Ag based contact materials.展开更多
To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallur...To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.展开更多
Ti3SiC2-reintbrced Ag-maJxix composites are expected to serve as eleclrical contacts. In this study, the wettability of Ag on a Ti3SiC2 subslxate was measured by the sessile drop melkod. The Ag-Ti3SiC2 composites were...Ti3SiC2-reintbrced Ag-maJxix composites are expected to serve as eleclrical contacts. In this study, the wettability of Ag on a Ti3SiC2 subslxate was measured by the sessile drop melkod. The Ag-Ti3SiC2 composites were prepared from Ag mad Ti3SiC2 powder mix- tures by pressureless sintering. The effects of compacting pressure （100-800 MPa）, sintering temperature （850-950~C）, mad soaking time （0.5-2 h） on the microslxucture mad properties of the Ag-Ti3SiC2 composites were investigated. The experimental results indicated that Ti3SiC2 paxticulates were uniformly distxibuted in flae Ag matrix, wiflaout reactions at the interthces between flae two phases. The prepared Ag-10wt%Ti3SiC2 had a relative density of 95% mad an electrical resistivity of 2.76 x 10 3 m~）＇cm when compacted at 800 MPa mad sintered at 950~C for 1 h. The incorporation of Ti3SiC2 into Ag was found to improve its hardness without substantially compromising its electrical conductivity; INs behavior was attxibuted to the combination of ceramic and metallic properties of the Ti3SiC2 reinforcement, suggesting its potential application in electrical contacts.展开更多
This study was conducted to do exposure assessment of the possible migration of antimony trioxide （Sb203） from Polyethylene terephthalate （PET） food contact materials （FCM）. Consumption Factor （CF） and Food-ty...This study was conducted to do exposure assessment of the possible migration of antimony trioxide （Sb203） from Polyethylene terephthalate （PET） food contact materials （FCM）. Consumption Factor （CF） and Food-type Distribution Factor （fT） were calculated from survey data with reference to the US FDA method. The most conservative migration conditions were obtained by testing Sb migration from PET FCM based on the Chinese national standard of GB/T 5009.101-2003[1].展开更多
Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken...Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.展开更多
According to the principle that fiber-like arrangement of reinforcing particles SnO2 paralleling to the direction of current is propitious to the electrical and mechanical performance of the electrical contact materia...According to the principle that fiber-like arrangement of reinforcing particles SnO2 paralleling to the direction of current is propitious to the electrical and mechanical performance of the electrical contact materials, we proposed and reported a novel precursor route used to prepare Ag/SnO,. electrical contact material with fiber- like arrangement of reinforcing nanoparticles. The mechanism for the formation of fiber-like arrangement of rein- forcing nanoparticles in Ag/SnO2 electrical contact material was also discussed. The as-prepared samples were char- acterized by means of scanning electron microscope （SEM）, optical microscope （OM）, energy-dispersive X-ray spectroscopy （EDX）, MHV2000 microhardness test, and double bridge tester. The analysis showed that the as-prepared Ag/SnO,, electrical contact material with fiber-like arrangement of reinforcing nanoparticles exhibits a high elongation of 24 %, a particularly low electrical resistivity of 2.08 μΩ. cm, and low arcing energy, and thus has considerable technical, economical and environmental benefits.展开更多
Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phas...Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phases and difficult component design.In this work,the Ag/SnO2 composites are prepared by selective laser melting.To get better performance,Ag/SnO2 composites with different energy density were studied.The microstructure was observed by field emission scanning electron microscope.In addition,reinforced SnO2 phase was characterized by X-ray diffraction and transmission electron microscope.The results indicated that the microstructure,relative density and hardness of are influenced by energy density,while Ag/SnO2 composites with homogeneous microstructure,high relative density,higher hardness and lower electrical resistivity can be obtained by proper energy density(E?68 J/mm^3).展开更多
基金Projects(11872257,11572358)supported by the National Natural Science Foundation of ChinaProject(ZD2018075)supported by the Hebei Provincial Education Department,China。
文摘The electrical contact and mechanical performances of Ag-SnO_(2) contact materials are often improved by additives,especially Cu and its oxides.To reveal the improvement mechanism of metal additive,the effects of Cu nanoparticles on the interface strength and failure behavior of the Ag-SnO_(2) contact materials are investigated by numerical simulations and experiments.Three-dimensional representative volume element(RVE)models for the Ag-SnO_(2) materials without and with Cu nanoparticles are established,and the cohesive zone model is used to simulate the interface debonding process.The results show that the stress−strain relationships and failure modes predicted by the simulation agree well with the experimental ones.The adhesion strengths of the Ag/SnO_(2) and Ag/Cu interfaces are respectively predicted to be 100 and 450 MPa through the inverse method.It is found that the stress concentration around the SnO_(2) phase is the primary reason for the interface debonding,which leads to the failure of Ag-SnO_(2) contact material.The addition of Cu particles not only improves the interface strength,but also effectively suppresses the initiation and propagation of cracks.The results have an reference value for improving the processability of Ag based contact materials.
基金Project(51274163)supported by the National Natural Science Foundation of ChinaProject(13JS076)supported by the Key Laboratory Research Program of Shaanxi Province,China+1 种基金Project(2012KCT-25)supported by the Pivot Innovation Team of Shaanxi Electrical Materials and Infiltration Technique,ChinaProject(2011HBSZS009)supported by the Special Foundation of Key Disciplines,China
文摘To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.
基金financially supported by the National Natural Science Foundation of China(Nos.51731004,51671054,and 51501038)“the Fundamental Research Funds for the Central Universities”in China
文摘Ti3SiC2-reintbrced Ag-maJxix composites are expected to serve as eleclrical contacts. In this study, the wettability of Ag on a Ti3SiC2 subslxate was measured by the sessile drop melkod. The Ag-Ti3SiC2 composites were prepared from Ag mad Ti3SiC2 powder mix- tures by pressureless sintering. The effects of compacting pressure （100-800 MPa）, sintering temperature （850-950~C）, mad soaking time （0.5-2 h） on the microslxucture mad properties of the Ag-Ti3SiC2 composites were investigated. The experimental results indicated that Ti3SiC2 paxticulates were uniformly distxibuted in flae Ag matrix, wiflaout reactions at the interthces between flae two phases. The prepared Ag-10wt%Ti3SiC2 had a relative density of 95% mad an electrical resistivity of 2.76 x 10 3 m~）＇cm when compacted at 800 MPa mad sintered at 950~C for 1 h. The incorporation of Ti3SiC2 into Ag was found to improve its hardness without substantially compromising its electrical conductivity; INs behavior was attxibuted to the combination of ceramic and metallic properties of the Ti3SiC2 reinforcement, suggesting its potential application in electrical contacts.
基金financially supported by the Beijing Natural Science Foundation-Sanyuan Joint FundingNo.15S00033
文摘This study was conducted to do exposure assessment of the possible migration of antimony trioxide （Sb203） from Polyethylene terephthalate （PET） food contact materials （FCM）. Consumption Factor （CF） and Food-type Distribution Factor （fT） were calculated from survey data with reference to the US FDA method. The most conservative migration conditions were obtained by testing Sb migration from PET FCM based on the Chinese national standard of GB/T 5009.101-2003[1].
基金Project (No. 502048) supported by the Natural Science Foundation of Hebei Province, China
文摘Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.
基金National Major Scientific&Technological Achievement Transformation Project
文摘According to the principle that fiber-like arrangement of reinforcing particles SnO2 paralleling to the direction of current is propitious to the electrical and mechanical performance of the electrical contact materials, we proposed and reported a novel precursor route used to prepare Ag/SnO,. electrical contact material with fiber- like arrangement of reinforcing nanoparticles. The mechanism for the formation of fiber-like arrangement of rein- forcing nanoparticles in Ag/SnO2 electrical contact material was also discussed. The as-prepared samples were char- acterized by means of scanning electron microscope （SEM）, optical microscope （OM）, energy-dispersive X-ray spectroscopy （EDX）, MHV2000 microhardness test, and double bridge tester. The analysis showed that the as-prepared Ag/SnO,, electrical contact material with fiber-like arrangement of reinforcing nanoparticles exhibits a high elongation of 24 %, a particularly low electrical resistivity of 2.08 μΩ. cm, and low arcing energy, and thus has considerable technical, economical and environmental benefits.
基金sponsored by the Natural Science Foundation of China (Grant nos. 51775208)the Hubei Science Fund for Distinguished Young Scholars (No. 0216110085)+2 种基金the National Key Research and Development Program “Additive Manufacturing and Laser Manufacturing”(No. 2016YFB1100101)Wuhan Morning Light Plan of Youth Science and Technology (No. 0216110066)the Academic frontier youth team at Huazhong University of Science and Technology (HUST)
文摘Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phases and difficult component design.In this work,the Ag/SnO2 composites are prepared by selective laser melting.To get better performance,Ag/SnO2 composites with different energy density were studied.The microstructure was observed by field emission scanning electron microscope.In addition,reinforced SnO2 phase was characterized by X-ray diffraction and transmission electron microscope.The results indicated that the microstructure,relative density and hardness of are influenced by energy density,while Ag/SnO2 composites with homogeneous microstructure,high relative density,higher hardness and lower electrical resistivity can be obtained by proper energy density(E?68 J/mm^3).
