Crystal Whisker Growth on Porous Coatings

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Crystal Whisker Growth on Porous Coatings

• Lorraine F. Francis, Department of Chemical
  Engineering and Materials Science, University of
  Minnesota

The goals of this research are to elucidate the
mechanism of crystal growth for needle-like KCl
whiskers on the surfaces of solution saturated
porous coatings, to control the whisker
dimensions, and to explore the applications of
the whiskers.

• Year 3 Results
• A systematic study of whisker growth on porous
  coatings under controlled experimental conditions
  was conducted, and results interpreted with
  transport models.
• (2) Visualization results show that salt solution
  rises to much higher levels in porous coatings
  than water
• (3) Whiskers form on bare substrate when
  nanoparticles are included in salt solution. This
  process is faster and requires lower relative
  humidity than whisker formation on porous
  coatings.

Porous Coating
Whisker Growth Zone
Glass Substrate
Initial liquid level
Final liquid level
Initial liquid level
Salt Solution Reservoir
Final liquid level
Humidity Control Chamber
Experiment set-up for whisker growth on porous
coating.
Digital images of whiskers grown on porous
coating from solution of varying KCl
concentration.
Digital image of whiskers grown on bare substrate
with nanoparticles in solution