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Trial Number 1

Trial Purpose:

Is electrostatic charge causing high contact angle

Date Run:


Experiment Procedure:

The purpose of this trial was to determine if an electrostatic charge was responsible for the high contact angles measured in the goniometry test performed on June 4. The cleaning process used is described in the previous report. In this test the bars were rinsed in deionized water and dried in an oven at 120 F for fifteen minutes prior to measuring the contact angle. The bars were allowed to sit overnight so they would return to ambient temperature. The contact angle was again measured at three sites on each bar using the procedure described in the previous log entry.

SUBSTRATE MATERIAL: 0.5"x0.25x12" Aluminum 6062 Bars
CONTAMINANTS: Mobilewax 2305
CONTAMINATING PROCESS USED: Bars contaminated at Aluminum Anodizing Job Shop by dipping into vat of masking wax

Trial Results:

Contact Angle Goniometry
  Contact Angle (degrees)
Bar Bottom Middle Top
A 83.63 90.31 91.00
B 96.69 96.22 90.28
C 94.22 94.31 92.88
D 86.91 93.53 94.59
E 80.94 94.34 92.75

Success Rating:

A cleanliness study, addressing only various analytical techniques.


The results of this test did not indicate a significant difference in the cleanliness between the test bars. The difference in contact angles for the bottom of the bars shows some difference in cleanliness. However, the high contact angles indicate the presence of significant microscopic contamination on all bars in all areas. This test eliminated the possibility of an electrostatic charge being responsible for the high contact angles. Laser goniometry was not able to show differences in cleanliness between test bars. It is possible that the coupons were cross contaminated during packaging and shipping, therefore resulting in microscopic contamination over the entire surface of the bars.
Further testing will be done to attempt to eliminate variables from the test procedure. Cleaning trials will be performed in the Surface Cleaning Lab on aluminum coupons contaminated at Aluminum Anodizing Job Shop.

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