A comparative study on the ageing behaviour of solder alloy-cu joint assemly using lead free solder and Sn-Pb eutectic solder alloy
IR@NML: CSIR-National Metallurgical Laboratory, Jamshedpur
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| Relation |
http://eprints.nmlindia.org/5715/
http://eprints.nmlindia.org/5715 |
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| Title |
A comparative study on the ageing behaviour of solder alloy-cu joint assemly using lead free solder and Sn-Pb eutectic solder alloy
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| Creator |
Ghosh, M
Kar, Abhijit Ghosh, R N Ray, Ajoy K |
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| Subject |
Materials Science
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| Description |
In the present investigation, Sn-Ag-In ternary alloy was used to join Cu substrate (SAI-Cu) and compared
with conventional Sn-Pb eutectic solder alloy–Cu assembly (SP-Cu). The melting point of the alloys was
found to be 192±1
o
C and 184±2
o
C respectively. The re-flowing was carried out above +30
o
C of the melting
point of the respective alloys for 30secs. Both the joints were aged at 100
o
C for 50-200hrs at a step of 50hrs.
Subsequently, structural characterization and mechanical property evaluation of the joints were performed.
In re-flowed condition, the shear strength of the SAI-Cu joint (~64MPa) is higher than SP-Cu joint
(~55MPa). The diffusion zone of the former is decorated with Cu 6 Sn 5 intermetallic phase, whereas the latter
contains both Cu 6 Sn 5 and Cu 3 Sn. The width of the reaction zone is more in case of SP-Cu joint with respect
to SAI-Cu joint. Isothermal aging of the solder assembly leads to deterioration of joint shear strength
accompanied by structural change in the diffusion zone. After 200hrs of aging the shear strength of SAI-Cu
joint is ~44.6MPa and the same becomes ~34.5MPa for SP-Cu joint. In both the cases, formation of Cu 6 Sn 5
and Cu 3 Sn has been observed which causes lowering of bond strength. Indium plays a vital role in
controlling the chemical reaction at the interface during reflowing and ageing. Hence, it is responsible for
betterment in mechanical properties.
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| Date |
2008
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| Type |
Conference or Workshop Item
PeerReviewed |
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| Format |
application/pdf
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| Language |
en
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| Identifier |
http://eprints.nmlindia.org/5715/1/ATSC-1002.pdf
Ghosh, M and Kar, Abhijit and Ghosh, R N and Ray, Ajoy K (2008) A comparative study on the ageing behaviour of solder alloy-cu joint assemly using lead free solder and Sn-Pb eutectic solder alloy. In: The 3rd Asian Thermal Spray Conference (ATSC 2008), 2008, Singapore. |
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