The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with C...The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with Cu,Ni and Cu/Ni,respectively,was carried out by electroless plating method.SiCp/Al composites were prepared by hot pressed sintering followed by hot extrusion.The results show that the surface modification of SiC particles plays an effective role,which is relative to the type of surface coating,and the interfacial bonding become stronger in the following order:untreated SiCp<Ni(Cu)-coated SiCp<Ni/Cu-coated SiCp.The Ni/Cu-coated SiCp/Al composites exhibit the best comprehensive mechanical properties,with ultimate tensile strength(σUTS)and fracture strain(εf)of 389 MPa and 6.3%,respectively.Compared with that of untreated-SiCp/Al composites,theσUTS andεf are enhanced by 19.3%and 57.5%.展开更多
Mg-6%Al-5%Pb(mass fraction) anodes with different contents of zinc were prepared by melting and casting.The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic t...Mg-6%Al-5%Pb(mass fraction) anodes with different contents of zinc were prepared by melting and casting.The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic test and electrochemical impedance spectroscopy(EIS).The microstructures and the corroded surfaces of these anodes were studied by scanning electron microscopy(SEM) and emission spectrum analysis(ESA).The phase structures and the corrosion products of the anodes were analyzed by X-ray diffraction(XRD).The results show that zinc promotes the grain refinement of Mg-6%Al-5%Pb anode and makes the average discharge potential of Mg-6%Al-5%Pb anode more negative during galvanostatic test.Mg-6%Al-5%Pb anode with the addition of 1%(mass fraction) zinc has the best electrochemical performance.The activation mechanism of zinc to Mg-6%Al-5%Pb anode is as follows:The hydrolyzation of dissolved Zn2+ ions reduces the pH value of the solution near the surface of the anode and accelerates the dissolution of Mg(OH)2 film;The precipitated Zn(OH)2 with similar structure as Mg(OH)2 combines with Mg(OH)2 film easily and makes it break down.展开更多
The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,mel...The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,melting point and corrosion performance of extruded Sn-9Zn solder alloys.The results reveal that the Zn-rich precipitates with spherical or needle-like shape in the Sn-9Zn-xCo alloys are refined remarkably by forming the γ-Co5Zn21 and Co2Sn2Zn Co-contained intermetallic compounds,though the melting point and eutectic reaction temperature decrease slightly.It is suggested that the corrosion property of the extruded Sn-9Zn-xCo alloys is improved significantly by adding the cobalt element,while the content should be controlled reasonably.Combining the corrosion morphology,the influence of cobalt content on the corrosion behavior of the Sn-9Zn-xCo alloys is analyzed in terms of the refined microstructure and the enhanced passive film stability.展开更多
基金Project(2017zzts111)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with Cu,Ni and Cu/Ni,respectively,was carried out by electroless plating method.SiCp/Al composites were prepared by hot pressed sintering followed by hot extrusion.The results show that the surface modification of SiC particles plays an effective role,which is relative to the type of surface coating,and the interfacial bonding become stronger in the following order:untreated SiCp<Ni(Cu)-coated SiCp<Ni/Cu-coated SiCp.The Ni/Cu-coated SiCp/Al composites exhibit the best comprehensive mechanical properties,with ultimate tensile strength(σUTS)and fracture strain(εf)of 389 MPa and 6.3%,respectively.Compared with that of untreated-SiCp/Al composites,theσUTS andεf are enhanced by 19.3%and 57.5%.
基金Project(JPPT-115-168) supported by the National Key Science and Technological Program of China
文摘Mg-6%Al-5%Pb(mass fraction) anodes with different contents of zinc were prepared by melting and casting.The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic test and electrochemical impedance spectroscopy(EIS).The microstructures and the corroded surfaces of these anodes were studied by scanning electron microscopy(SEM) and emission spectrum analysis(ESA).The phase structures and the corrosion products of the anodes were analyzed by X-ray diffraction(XRD).The results show that zinc promotes the grain refinement of Mg-6%Al-5%Pb anode and makes the average discharge potential of Mg-6%Al-5%Pb anode more negative during galvanostatic test.Mg-6%Al-5%Pb anode with the addition of 1%(mass fraction) zinc has the best electrochemical performance.The activation mechanism of zinc to Mg-6%Al-5%Pb anode is as follows:The hydrolyzation of dissolved Zn2+ ions reduces the pH value of the solution near the surface of the anode and accelerates the dissolution of Mg(OH)2 film;The precipitated Zn(OH)2 with similar structure as Mg(OH)2 combines with Mg(OH)2 film easily and makes it break down.
基金Project(2017YFB0305700)supported by the Ministry of Science and Technology of ChinaProjects(51490660,51490664)supported by the National Natural Science Foundation of ChinaProject(2017YFB0305700)supported by the National Key Research and Development Project of China。
文摘The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,melting point and corrosion performance of extruded Sn-9Zn solder alloys.The results reveal that the Zn-rich precipitates with spherical or needle-like shape in the Sn-9Zn-xCo alloys are refined remarkably by forming the γ-Co5Zn21 and Co2Sn2Zn Co-contained intermetallic compounds,though the melting point and eutectic reaction temperature decrease slightly.It is suggested that the corrosion property of the extruded Sn-9Zn-xCo alloys is improved significantly by adding the cobalt element,while the content should be controlled reasonably.Combining the corrosion morphology,the influence of cobalt content on the corrosion behavior of the Sn-9Zn-xCo alloys is analyzed in terms of the refined microstructure and the enhanced passive film stability.
