FOS CHAMBER
This is the current chamber used for Flowers of Sulfur Testing. The chamber consists of a box with a
partition and a moving lid, a planetary gear system with a stepper motor, a humidity sensor, and a fan.
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CHAMBER MECHANICS
The chamber’s box contains two salt solutions with a partition that separates the two.
The box’s lid allows for only one salt solution to be exposed to the chamber at a time,
moving back and forth through the use of a stepper motor and a set of planetary
gears with a scotch yoke. This allows the salt solutions to cycle the chamber’s
humidity. The stepper motor is controlled by an Arduino microcontroller. The Arduino
is currently programmed to record the chamber’s humidity and temperature as well as
move the box’s lid every 12 hours (for a 24 hour complete humidity cycle).
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SALT SOLUTIONS
The two salt solutions currently being used to control the humidity during the Flowers of Sulfur
experiments are Lithium Chloride and Potassium Chloride.
CHAMBER HUMIDITY ON A 24 HOUR CYCLE
Potassium Chloride Solution
Expected Relative Humidity: ~79.49% @ 70°C
Testing Reveals: ~69% after 12 hours of exposure
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Lithium Chloride Solution
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400g of LiCl
400ml of water
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Expected Relative Humidity: ~10.75% @ 70°C
Testing Reveals: ~45% after 12 hours of exposure
Humidity
Temperature
80
% RELATIVE HUMIDITY, DEGREES CELCIUS
400g of KCl
400ml of water
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70
60
50
40
30
20
10
0
60
80
100
120
140
160
180
TIME (HOURS)
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Note: Tests are run at 70°C.
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EXPERIMENT SETUP
The most recent FOS experiment was run with six 2”x3” fresh silver immersion board samples suspended
4” off the ground. Additionally, four 2.5” diameter beakers with ¼” of elemental sulfur were placed at
each corner surrounding the sample tray. The chamber was then placed in an oven at 70°C for 21 days
with lid movements occurring every 12 hours (for a 24 hour complete humidity cycle).
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EXPERIMENT RESULTS
Several instances of creep corrosion were seen on all six samples.
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EXPERIMENT RESULTS
Several instances of creep corrosion were seen on all six samples.
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