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• 15 • 800-356-1688 • 2005 vol. 3
treated electropolished, electropolished, and standard tubing are compared in
Figure 1. Treated electropolished tubing reached the 98% saturation limit in
30 minutes, compared to 60 minutes for electropolished tubing. Standard tub-
ing could only achieve a 96% uptake, after 180 minutes.
After the tubing was stabilized with 1ppm of moisture, dry-down properties
were measured. Moisture dry-down curves for the three tubing treatments
show treated electropolished tubing achieved dry-down in 35 minutes, elec-
tropolished tubing required 65 minutes, and standard tubing required 175
minutes (Figure 2). Table 1 compares time to various dry-down levels for tub-
ing saturated with 10ppm of moisture.
Superior Corrosion Resistance: Silcosteel®-CR
In addition to rapid wet-up and dry-down, the other key advantage of Restek
treatment for 316L stainless steel is a dramatic improvement in corrosion
resistance. The amorphous silicon layer is insoluble in many acidic environ-
ments. Figures 3, 4, and 5 briefly summarize the results of corrosion testing by
ASTM methods. Comparisons between treated and untreated test samples
illustrate the improvements in corrosion resistance offered by Silcosteel®-CR
treatment. For more information about corrosion resistance, request infor-
mation packet 59048, or visit our website.
When moisture considerations and corrosion concerns arise in transfer of
ultra-high purity gas streams, Restek treated tubing and system components
will dramatically improve dry-down, reduce contamination from moisture
carryover, and extend periodic maintenance cycles.
Reference
1. Relative Response Time of True Tube™ when Measuring Moisture Content in a Sample StreamTest Report,
Haritec Scientific & Engineering Support, Calgary, Alberta, Canada, May 2004.
Tubing used in the wet-up / dry-down experiments was supplied by Cardinal UHP (St. Louis, MO). All tubing was
tested as 100 foot coils of 1/4" OD x 0.020" wall 316L stainless steel. Electropolished tubing had a surface rough-
ness of 10 to 15 microinches. Siltek® treated tubing was finished with 5µm of amorphous silicon, followed by a
surface functionalization to increase inertness and hydrophobicity.
Reference courtesy of O’Brien Corporation, available on request from Restek.
Silcosteel®-CR treated untreated
Silcosteel®-CR treated untreated
Figure 4 Silcosteel®-CR treated 316L
stainless steel shows no sign of attack after
4000-hour salt spray exposure (ASTM B117).
Figure 5 Silcosteel®-CR treated 316L
stainless steel shows no crevice corrosion
and only slight pitting corrosion after 72-
hour exposure to ferric chloride; untreated
steel exhibits severe crevice corrosion.
Siltek ® Treated 316L Tubing**
Silcosteel®-CR -Treated 316L Tubing**
Silcosteel®-CR-Treated Electropolished Tubing
Siltek ®-Treated Electropolished Tubing
Siltek®- and Silcosteel®-CR-Treated Electropolished Tubing
• Exceptional inertness.
• Improved reliability and reproducibility; longer lifetime.
• Use with treated fittings for the most inert sample pathway available.
1/8 " OD: 5 ft. to 100 ft. in one continuous coil; 1/4 " OD: 5 ft. to 300 ft. in one continuous coil.
Longer lengths will be more than one coil.
**0.035" wall thickness
Note: (required length in meters) x (3.2808) = length in feet.
Price-per-foot
ID OD cat.# 5-24 ft. 25-99 ft. 100-299 ft. >300 ft.
0.085" 1 /8" 22538
0.180" 1 /4" 22539
0.055" (1.40mm) 1/8" (3.18mm) 22508
0.180" (4.57mm) 1/4" (6.35mm) 22509
0.085" 1 /8" 22536
0.180" 1 /4" 22537
Price-per-foot
ID OD cat.# 5-24 ft. 25-199 ft. 200-399 ft. >400 ft.
0.055" (1.40mm) 1 /8" (3.18mm) 22896
0.180" (4.57mm) 1 /4" (6.35mm) 22897
Coiled, Treated, Seamless 316 Grade Stainless Steel Tubing
Figure 3 In chloride environments,
Silcosteel®-CR treated stainless steel
outperforms untreated metal by an order
of magnitude (ASTM G 48, Method B).
0 50 100 150 200 250
Untreated 316 SS
Silcosteel®-CR
weight loss in grams per square meter
for more info
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