The Development of Tin Whiskers in Lead-free
SolderJoseph Garvey and Rachel Lindbergh – Co-Principal Investigators
Gabriel Voigt – Co-Investigator
Palmetto Scholars AcademyNorth Charleston, SC
Tin Whiskers● Small, crystalline structures● 0.006 to 10 micrometers thick
and up to 10 millimeters long● Have been known to cause
short circuits ● Causes are unknown--
theories say they could be caused by compression
Tin whiskers have degraded or destroyed…
● Galaxy IIIR● Galaxy VII ● Solidaridad 1● OPTUS B1● DBS-1● PAS-4● DirecTV 3
● Pacemakers● Patriot and Phoenix
missiles● Cellphones● Computers
Experiment Design
▪ 120 mm x 5 mm x 2 mm (99.3% tin, 0.7% copper) rectangular piece of tin made from tin solder (quantity of 4)
▪ 120 mm x 5 mm x 2 mm fiberglass, copper clad circuit board (quantity of 4) with a maximum of 4 mL of copper cladding; fiberglass is 0.1 cm in height, copper cladding is .06 cm in height
▪ Max of 3g of tin solder (percentage by weight): maximum of 97% tin; maximum of 4.2% silver; maximum of 3% hydrogenated rosin; maximum of 0.9% copper
▪ Polyethylene foam packing cylinders for securing test bed and PCBs in tube (10 cylinders -- 0.5 cm in diameter, 1.27 cm in depth)
Our FME
Key for test tubeThis is a depiction of what our type 1 FME will look like.Red= electroplated tin testbed 120 mm x 5 mm x 2mmOrange= printed circuit board 120 mm x 5 mm x 2 mmBlue= Polyethylene foam packing 0.5 cm in diameter, 1.27 cm in depthBlack= plugs to seal the test tubeWhite= test tube
Experiment Design
• 4 Type 1 FME’s will be constructed in the same manner according to the instructions above.
• 1 Type 1 FME will be randomly selected for spaceflight.
• The ground truth FME’s will be static but oriented in a different position:
• One ground truth FME will be oriented vertically
• One ground truth FME will be oriented upwards
• One ground truth FME will be oriented downwards
Our Goal
We want to determine whether spaceflight affects the development of tin whiskers
We expect that the FME that goes to the ISS will develop more tin whiskers than the ground truths.
Data Analysis
● Mass will be measured with a microscale from College of Charleston
● Solder will be analyzed with a scanning electron microscope from National Oceanic and Atmospheric Administration
AcknowledgementsPartners• Space and Naval Warfare Systems
Command (SPAWAR)• Center for the Advancement of
Science in Space (CASIS)• National Center for Earth and
Space Science Education• College of Charleston• Citadel University• Medical University of South
Carolina (MUSC)• National Oceanic and Atmospheric
Administration (NOAA)
Sponsors• ISHPI• Google• South Carolina Space Grant
Consortium• Center for the Advancement of
Science in Space (CASIS)