Research
Early Design Review of Boundary Scan To Enhancing Testability
Fatigue and Shear Properties of High Reliable Solder Joints
Liquid Dispensed Thermal Materials for High Volume Manufacturing
Effect of Process Changes and Flux on Mid-Chip Solder Balling
Effect of Fine Lead-Free Solder Powder on the Reflow Property Pastes
Embedded Fibers Enhance Nano-Scale Interconnections
Electronic Packages and Modules Based on Embedded Die Technologies
3D Printed Electronics for Printed Circuit Structures
MORE RESEARCH
Latest Industry News
Foxconn to Shift Some Apple Production to Vietnam
GM Opens Up a New Front in Its Battle With Tesla: Batteries
Chinese handset vendors keenly building up inventory
Apple suppliers' exodus from China won't slow down under Biden
Exposing Apple Mini M1 SoC
Taiwan PC monitor shipments to drop in 4Q20, says Digitimes Research
The Best Smartphones
Autonomous Vehicle Software Analyzes and Predicts Driving Events
MORE INDUSTRY NEWS

Microalloyed Sn-Cu Pb-Free Solder for High Temp



Microalloyed Sn-Cu Pb-Free Solder for High Temp
While susceptibility to tin whisker growth remains a barrier to the transition to Pb-free, there is now general acceptance that there are reliable alternatives.
Materials Tech

DOWNLOAD

Authored By:


Keith Howell, Keith Sweatman, Motonori Miyaoka, Takatoshi Nishimura
Nihon Superior Co., Ltd., Osaka, Japan

Xuan Quy Tran, Stuart McDonald, Kazuhiro Nogita
The University of Queensland, Brisbane, Australia

Summary


While the search continues for replacements for the highmelting-point, high-Pb solders on which the electronics industry has depended for joints that maintain their integrity at high operating temperatures, an investigation has been made into the feasibility of using a hypereutectic Sn-7Cu in this application.

While its solidus temperature remains at 227 degrees C the microstructure, which has been substantially modified by stabilization and grain refining of the primary Cu6Sn5 by microalloying additions of Ni and Al, makes it possible for this alloy to maintain its integrity and adequate strength even after long term exposure to temperatures up to 150 degrees C.

In this paper the results of a study of microstructural evolution during elevated temperature aging and in particular the growth of intermetallics at the interface between Cu and Ni substrates will be reported as well as the results of elevated temperature mechanical testing.

Conclusions


The results reported here indicate that a Sn-7Cu alloy in which the particle size of the primary Cu6Sn5 phase has been refined by an addition of Al appears to have strength at least comparable with that of Sn-95Pb at temperatures up to 220 degrees C. The reduction in strength that occurs as the Cu6Sn5 coarsens suggests that the relatively high strength of the Sn- 7Cu alloy results from the fine dispersion of Cu6Sn5 particles that results from the controlled addition of Al.

Initially Published in the SMTA Proceedings

Comments

No comments have been submitted to date.

Submit A Comment


Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name


Your Company
Your E-mail


Your Country
Your Comments



Board Talk
Modify Rework Procedures for Assemblies Fabricated Using OSP?
What Causes Solder Icicles During Wave Soldering
Review of Tin-Copper and Tin-Nickel Intermetallic Thickness
Can High Particle Concentrations Impact PCB Assembly?
Trouble With Skewed DPAK Components
Moisture Barrier Bag Issues
How to Reduce Voiding on QFN Components
Can Mixing Wave Solder Pallets Cause Contamination?
MORE BOARD TALK
Ask the Experts
Reflow Oven Calibration Schedule
Insufficient Plated Hole Fill with Electrolytic Capacitors
Through Hole Connector Solder Joint Hole Fill
Selective Solder System Purchased At Auction
Out-gassing and Cleaning
Stencil Cleaning Procedure
Challenging Cleaning Problem
Selective Printing for BGA Components
MORE ASK THE EXPERTS