Table 1 summarizes the results of this experi-
ment. Silcosteel®-CR treated316L stainless steel
samples exhibited anorder ofmagnitude less cor-
rosion, compared tobare samples.As seen in
Figures 2 and3, Silcosteel®-CR treated coupons
exhibitedno crevice corrosion,whileuntreated
coupons exhibited severe crevice corrosion.
Silcosteel®-CR treated coupons experiencedonly
slight pitting corrosionduring this aggressive test.
At-a-Glance
Product
Information
fromRestek
Silcosteel
®
-CR
Table2
Silcosteel®-CR treatment greatly reduces corro-
sion rates in chloride solutions. (Corrosion rate inmpy
(mil per year) determinedbyelectrochemical testing.)
Silcosteel
®
-CR Bare Steel
Improvement
Neutral Solution
(316L)
100ppm chloride
0.0006
0.03
49X
3000ppm chloride 0.0009
0.03
32X
5000ppm chloride 0.001
0.03
29X
Acidic Solution (1NH
2
SO
4
)
100ppm chloride
0.05
0.45
8X
3000ppm chloride 0.05
0.83
16X
5000ppm chloride 0.07
0.84
11X
Table3
Breakdownor pittingpotential, E
b
, inmillivolts,
determinedbyelectrochemical testing.
Silcosteel
®
-CR
Bare Steel
Neutral Solution
(316L)
100ppm chloride
>3000
674
3000ppm chloride
1460
370
5000ppm chloride
1590
285
Acidic Solution (1NH
2
SO
4
)
100ppm chloride
1128
580
3000ppm chloride
927
370
5000ppm chloride
983
563
Table4
Corrosionof Silcosteel®-CR treated316L
stainless steel versusbare304 stainless steel at
3000ppmCl - concentration.
Silcosteel
®
-CR Bare Steel Improvement
Neutral Solution
(304)
Corrosion Rate, mpy
0.0009
0.06
66X
Breakdown Potential, E
b
1460
361
Acidic Solution (1NH
2
SO
4
)
Corrosion Rate, mpy
0.05
1.14
22X
Breakdown Potential, E
b
927
587
Table5
Corrosionpotential, E
c
, inmillivolts, for
Silcosteel®-CR treated316L stainless steel.
Neutral Solution
E
c
100ppm chloride
-188mV
3000ppm chloride
-418mV
5000ppm chloride
-420mV
Acidic Solution (1NH
2
SO
4
)
100ppm chloride
-782mV
3000ppm chloride
-843mV
5000ppm chloride
-863mV
CyclicPolarizationElectrochemical CorrosionTestingof Silcosteel®-CRTreated316LStainless
Steel Coupons andBare316LandBare304Stainless Steel Coupons, byASTMG61
Sampleswere tested in accordancewithASTMG61 in acidic andneutral aqueous solutions, at 23ºC, at
three chloride ion (Cl - ) levels.Tables 2 and3 summarize the test results: Silcosteel®-CR treated316L
stainless steel coupons outperformedbare 316L stainless steel by a factor of approximately 50 inneutral
chloride solutions, andby approximately 10 in acidic chloride solutions.At a chloride concentrationof
3000ppm, Silcosteel®-CR treated316L stainless steel coupons outperformed304 stainless steel coupons
by a factor of approximately 65 inneutral solutions andby approximately 20 in acidic solutions.Table 4
summarizes the test results for Silcosteel®-CR treated316L stainless steel andbare 304 stainless steel.
Table 5 summarizes the corrosionpotential, E
c
, for Silcosteel®-CR treated316L stainless steel.
800-356-1688
★
814-353-1300
Figure2
Silcosteel®-CR treated316L stainless steel
coupons showno crevice corrosionandonly slight
pitting corrosion.
Figure3
Bare316L stainless steel coupons exhibit
severe crevice corrosion.
Table1
Silcosteel®-CR treatedcoupons show littleweight
lossafter exposure to6%w/w ferricchloride solution.
Sample
Weight Loss (g/m
2
)
Silcosteel
®
-CR sample 17
19
Silcosteel
®
-CR sample 28
25
Silcosteel
®
-CR sample 47
25
Bare Steel sample 27
231
Bare Steel sample 34
209
Bare Steel sample 37
228
