Diffusion barrier properties of electroless Ni-Fe-P coatings in Zn-5Al solder joints
Currently,lead-free high temperature solders for replacing high lead solders(Pb>85wt.%)have attracted much interests in high temperature power electronics.Zn-Al alloys show considerable potential to replace high lead solders because of its low cost,good thermal mechanical and electrical properties.However,the extravagant growth of the Cu-Zn intermetallic compounds(IMCs)significantly restrict its wide application.Therefore,an excellent and robust diffusion barrier at high temperature is urgently needed to prevent the reaction of Zn-based solders with Cu substrates.In this paper,a ternary electroless Ni-Fe-P metallization was fabricated upon Cu substrates.Afterwards,the Ni-Fe-P/Zn-5Al solder joints were fabricated after long solid-liquid reaction up to 30 min to examine the diffusion barrier effects of Ni-Fe-P alloys.The interfacial microstructure of IMC was observed from the cross-section and top view.A thin and continuous Al3Ni2 layer of 0.8μm(after 1 min)emerged at the Ni-Fe-P/Zn-5Al interface continuously grew to 3.35μm after reaction duration of 30 min.As a result,the electroless Ni-Fe-P coating successfully prevents the reaction between Cu and Zn atoms and lead to a slow growth rate coefficient of Al3Ni2(6.832×10-2μm/s1/2),showing a potential as a good diffusion barrier for power electronic devices.
Electroless Ni-Fe-P coatings Zn-5Al solder Diffusion barrier property Interfacial reaction
Han Zhang Zhiwen Chen Juan Peng Li Liu
School of Materials Science and Engineering,Wuhan University of Technology Wuhan,Hubei,China The Instititue of Technological Science,Wuhan University Wuhan,Hubei,China School of Materials Science and Engineering,Wuhan University of Technology Wuhan,Hubei,China;State K
国际会议
上海
英文
589-592
2018-08-08（万方平台首次上网日期，不代表论文的发表时间）