Researching On Preparation And Properties Of Spherical Y₂O₃ Reinforced Ag Matrix Composites

Ag-based composite reinforced by the ceramic particles is one of the most widely used and largely consumed contact materials.To further improve the electrical conductivity and antiwelding behavior of Ag/MeO contacts,monodispersed spherical Y2O3 were used as ceramic reinforced phase to prepare the spherical Y2O3 reinforced Ag matrix composites in this article.Urea homogeneous precipitation method were adopted to synthesis monodispersed spherical Y2O3,and the impacts of coating number and urea concentration on the particles size of Y2O3 precursors were discussed briefly in this paper;The Ag/spherical Y2O3 composite powders were prepared by the means of chemical reduction and ball milling,respectively,and the preparation process,the content of Y2O3 and the thermal treatment of Ag powders,which influence the morphology of composite powders were analyzed;Hot pressed sintering was used to fabricated the spherical Y2O3 reinforced Ag matrix composites,and we also studied the effects of the heat treatment of Ag powders,the amounts of Y2O3 and re-pressing on the microstructure,mechanical physical and electricity properties of materials;Through the test of arc erosion on the composites,the feasibility of using spherical Y2O3 reinforced Ag matrix composites as electrical contacts was explored.The main conclusions are as follows:(1)The particle size of spherical Y2O3 precursor prepared is 100?1270 nm in this experiment,and the particle size increases with the number of coating,and decreases with the increase of urea concentration.The spherical Y2O3 of 400 nm calcination temperature is 900?;(2)Ag/spherical Y2O3 composite powders prepared by chemical reduction method,spherical Y2O3 dispersed in Ag particles,the size of Ag particles decreased with the increase of yttrium oxide content,the particle size was about 1 ?m;The Ag/Y2O3 composite powder obtained by silver powder has irregular clusters,in which the spherical Y2O3 is dispersed in the cluster.The composite powder is irregular in shape and the size range is 15?44 ?m,and Y2O3 on the Ag surface.With the increase of the content of Y2O3,the lamellar thickness of the lamellar layer is not obvious.(3)After hot pressing,the spherical Y2O3 particles were dispersed in the silver matrix,and the spherical Y2O3 particles in the silver matrix were distributed in the silver matrix.The composite The density,conductivity and elongation of the composites decreased with the increase of Y2O3 content,and the hardness and tensile strength of the composites decreased first and then decreased with the increase of Y2O3 content.The properties of the composites were deteriorated by silver powder calcination;The relative density of the Ag-based composites was 98%,the hardness(HV)was 97,the conductivity was 50.5 MS/m,and the tensile strength was 222.0 MPa.The properties of the composites were investigated by X-ray diffractometry.,elongation of 13.8%,arc erosion experiment,the least amount of material transfer,is expected to be used in the field of electrical contact.