Anomalous growth of interfacial intermetallic compounds on (111)-oriented nanotwinned Cu substrate

The interfacial reactions of Sn–Zn based solder on Cu and Cu/Ni–P/Cu–plating substrates under aging at 150 °C were investigated in this study. The compositions of solders investigated were Sn–9Zn, Sn–8.55Zn–0.45Al, and Sn–8.55Zn–0.45Al–0.5Ag solders in weight percent. The experimental results indicated that the Cu substrate formed Cu5Zn8 with the Sn–9Zn solder and Al–Cu–Zn compound with Al–containing solders. However, it was detected that Cu6Sn5 formed at the Sn–9Zn/Cu interface and Cu5Zn8 formed at the Al–containing solders/Cu interface after aging for 1000 h. When it contacted with the Cu/Ni–P/Au substrate, the Sn–9Zn solder formed Au–Zn compound, and the Al–containing solders formed Al–Cu–Zn compound at the interface. After a long aging time, the intermetallic compounds existing between solders and the Cu/Ni–P/Au metallization layers almost did not grow. It was found that the interdiffusion between solders and Cu/Ni–P/Au was slower than that with Cu under aging. Furthermore, the addition of Ag to Sn–Zn solder resulted in the formation of AgZn3 particles at the interface.

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The Role of Ti Inoculation of Al-Zn-Si Coating Alloys on the Formation of Intermetallic Compounds by Interaction with Solid Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.560.97 ◽

2007 ◽

Vol 560 ◽

pp. 97-102 ◽

Cited By ~ 3

Author(s):

Felipe García ◽

Armando Salinas-Rodríguez ◽

Enrique Nava-Vázquez

Keyword(s):

Intermetallic Compounds ◽

Liquid Alloy ◽

Interfacial Layer ◽

Intermetallic Layer ◽

Coated Steel ◽

Acid Dissolution ◽

Steel Strips ◽

Si Content ◽

Interfacial Intermetallic Compounds

The reaction between solid steel and liquid Al-Zn-Si alloy leads to the formation of a solid intermetallic interfacial layer. In the case of industrial Al-43.5Zn-1.5Si coated steel strips, the thickness of the intermetallic layer is on average 1.35 μm and the kinetics of the reaction is controlled by the effect of Si on Al and Fe diffusivities through the solid intermetallic layer. In this paper it is shown that the thickness of the intermetallic interfacial layer decreases as the Si content in the liquid alloy increases. EDXS microanalysis at the interface of industrial coated steel strips shows that the interfacial intermetallic compounds are chemically similar to those formed in the bulk of Al-43.5Zn-1.5Si liquid baths in continuous coating lines. Differential acid dissolution of the coatings reveals that the intermetallic layer is not planar at the interface with the coating overlay and is formed by grains of different size and chemical composition. Addition of minute quantities of Ti to the Al-Zn-Si liquid alloy causes changes in the morphology of the intermetallic layer and an overall refining of the microstructure.

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Investigation Of Intermetallic Compounds In Sn-Cu-Ni Lead-Free Solders

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0163 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1511-1515 ◽

Cited By ~ 3

Author(s):

E. Nagy ◽

F. Kristaly ◽

A. Gyenes ◽

Z. Gacsi

Keyword(s):

Intermetallic Compounds ◽

Diffraction Method ◽

Lead Free ◽

Structural Behaviour ◽

Cu Content ◽

Soldering Process ◽

Cu Alloys ◽

Complex Structural ◽

Interfacial Intermetallic Compounds ◽

Lead Free Solders

Abstract Interfacial intermetallic compounds (IMC) play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint. In the soldering process of Sn-Cu alloys, Cu6Sn5 intermetallic compounds are formed. The complex structural behaviour of Cu6Sn5 IMC is temperature- and composition-dependent and it is long since subject to scientific research. The Cu6Sn5 phase basically exists in two crystal structures: hexagonal η-Cu6Sn5 (at temperatures above 186°C) and monoclinic η’-Cu6Sn5 (at lower temperatures). In the presence of Ni in the solder, the η-η’ transformation does not occur, therefore, the η-Cu6Sn5 phase remains stable. In this study the role of Ni in the (Cu,Ni)6Sn5 intermetallic compound in Sn-Cu lead-free solders was examined. Sn-Cu alloys with different Cu content (0.5 to 1 mass%) were modified through Ni addition. The morphology of the intermetallic compounds of the modified Sn-Cu alloys was investigated by optical microscopy (OM) and scanning electron microscopy (SEM), the IMC phases were examined with X-ray diffraction method (XRD).

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