Microstructural Evolution of AuSn20/Ni Joint during Annealing

Abstract:

The AuSn20 (mass fraction) solder was prepared by laminate rolling-annealing method, the AuSn20/Ni solder joints were prepared by the reflow process. The effects of the aging times and temperatures on the microstructure and shear strength of the AuSn20/Ni joints were investigated by the scanning electron microscope (SEM) with an energy dispersive X-ray (EDX). The results show that, the AuSn20 solder is composed of lamellar ζ-Au5Sn and δ-AuSn phases after preparing and the melting point approximates to the eutectic temperature of Au-20Sn alloy. A eutectic ζ-Au5Sn+δ-AuSn microstructure forms in the solder matrix and hexagon (Ni,Au)3Sn2 intermetallics nuclear at the as-reflowed joint. Then the AuSn20/Ni joint was aged at 150 and 200 °C for various times，and the thickness of the IMC layer at 150 °C changes few with the aging time increasing from 150 h to 1000 h, however, it grows rapidly at 200 °C.

• Periodical: Advanced Materials Research (Volumes 634-638)
• Pages: 2865-2871
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.634-638.2865
• Online since: January 2013
• Authors: Xiao Feng Wei, Ri Chu Wang, Yan Feng
• Keywords: AuSn20 Solder, AuSn20/Ni Joints, Interfacial Reaction, Intermetallic Compound (IMC)

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