| Abstract:Silver based contact materials has been widely applied in the field of low voltage apparatus as its good comprehensive performance.Among them,Ag-SnO2 electric contact material and Ag-Ni electrical contact materials are due to the good electrical conductivity,thermal conductivity,processing performance and low and stable contact resistance obtained material workers of all ages.In recent years,the workers of the above two kinds of contact materials to do a lot of research in terms of performance improvement.Preparation process as a starting point,this paper with green choice physical?high energy ball mill method?and the chemical method?liquid phase reduction method?,the preparation of Ag-Ni-SnO2 electric contact material,aims to nickel element to reduce Ag-SnO2 of silver content in electrical contact materials,at the same time,improve the wettability between the oxide with silver substrate;Second,through Ag-Ni add SnO2electric contact material to improve Ag-Ni arc ablation resistance characteristics of electrical contact materials and welding resistance.On the basis of a large number of experiments to the following conclusion:?1?Using high-energy ball milling method to prepare Ag-Ni-SnO2 composite powder,among them,the silver content is 75wt%,nickel and tin oxide quality ratio is 1?1,respectively 1.5?1,2?1,2.5?1,through the test of electric contact density,hardness,electrical conductivity,and then analysis the micro-structure,the result shows:the best quality of nickel and tin oxide ratio was 1.5?1,the electric contact material conductivity is 45.6%IACS,104.9 HV hardness,density of 8.985 g·cm-3,relative density is 92.73%.?2?Industrial production preparation of Ag-Ni-SnO2 resistant to high voltage electrical contact materials,contact materials of intercepting value is 3.28 A,the arc life is 16.08,and the material surface is flat after arc erosion and there is no oxide concentration,the result shows that the Ag-Ni-SnO2 electric contact material has the high resistance welding performance.?3?Ag-Ni contact material prepared by chemical liquid phase reduction method in SnO2 electric contact material,determine glucose as the reducing agent,silver nitrate concentration is 0.37mol/L composite powder was prepared,with powder metallurgy process preparation of Ag-Ni-SnO2 electric contact material,the preparation route is:Ag-Ni-SnO2 composite powder—powder annealing?600?,2h,nitrogen protection?—cold press molding?300Mpa,5min?—vacuum sintering?850?,5h?—the complex pressure?600Mpa,1min?—annealing?820?,3h?—the second pressure?700Mpa,1min?—annealing?750?,3h?—surface treatment.Finally,The conductivity of Ag-Ni-SnO2electric contact material is 43.09%IACS,density is 8.229g·cm-3,hardness is 56.53HV. |
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