1. SilcoTek Corporation Gary Barone
Using Chemical Vapor Deposition Processes to Enhance the Corrosion Performance of Steel Substrates
SilcoTek Corporation
Gary Barone

2. Topics About Us Products and Applications Product Performance
Conclusion/Future Product Development

3. Semiconductor/Research
MARKET AREAS
APPLICATION AREAS
SilcoNert™: Inertness
Silcolloy™:Anti-Corrosion
SilcoKlean™: Anti-Coking
SilcoGuard™: Ultra-High Vacuum
Analytical
Pharmaceutical
Environmental
Petrochemical
Chemical
Process
Semiconductor/Research
SilcoNert 1000 (original inert coating)
SilcoNert 2000 (most advanced inert coating) available through Swagelok. SilcoNert 2000 is used in sampling, instrumentation, gas chromatography consumables, process monitoring, emissions monitoring, oil and gas production/distribution and refining.
Silcolloy (corrosion resistant coating) used in acidic corrosion environments. Recommended for chloride corrosion applications such at marine/salt corrosion, HCl exposure.
SilcoGuard (low out gassing, ultra high vacuum coating) developed for high vacuum environments where high pumping speed is needed for improved productivity. UHV coating will allow up to 14x faster pump down.
SilcoKlean (anti coking coating) developed to prevent catalytic coking in high temperature fuels and lubrication environments. SilcoKlean will reduce carbon build-up by 8x.
Automotive

4. Basic Manufacturing Process
Receive items
Document – digital, customer contact
Clean
Standard: caustic ultrasonic bath, 2 systems
Custom: solvation via other means
Chemical Vapor Deposition (CVD) Process
Vacuum
400ºC
silicon-based deposition
Pack, ship
Parts are received and inspected. Customer is notified of part receipt. Parts are cleaned in an ultrasonic bath and queued for treatment. Batch CVD process ovens heat parts under vacuum. Semiconductor gas fills the oven chamber coating the parts. All surfaces exposed to the process gas will be coated. SilcoTek cannot mask select areas of a part due to the high process temperatures.
After coating, parts are cleaned, inspected, packaged and shipped. The customer is contacted regarding order status and shipping.

5. Product Characterization
Amorphous silicon CVD coating
Density: g/cm3
Melting point: 1410oC
Max operating temp.
600oC to 1000oC: Silcolloy; SilcoNert 1000; SilcoGuard
450oC SilcoNert 2000
1200A to 5um thickness, minimal smoothing of surface

6. Coating Cross Section 316 SS
Cross section of substrate/coating shows minor variations in coating thickness. Coating at this magnification appears to show a surface coating. But Auger depth profile shows layer diffuses into the substrate.

7. Auger Depth Profile
Auger shows a 1200A silicon layer depth (red). Iron (green) shows the start of the substrate layer at 35min. Subsequent Auger and GD-OES data show iron/silicon interface can be up to several hundred angstroms thick. Providing a layer which is diffused (or meshed) into the surface, similar to Velcro. This diffusion creates a durable, flexible layer that will not delaminate.

8. Coating Capabilities: Substrates
Tubing:
0.004” to 0.5” ID
2000+ ft. continuous lengths
Complex geometry parts (inside and out)
Fittings, valves, frits
Block manifolds, sample vessels
custom parts
Restek is able to coat continuous lengths of tubing of feet. Custom components of complex geometry can be coated.
Fittings, valves, frits can also be coated.

9. Sizes of reaction chambers
“Standard” vessels:
12” diameter cylinder w/ 56” height
6” diameter cylinder w/ 72” height
10” diameter cylinder w/ 18” height
21” diameter cylinder w/ 42” height
Large processing oven:
27” diameter x 26” deep
Walk-in Oven:
4 feet by 4 feet by 5 feet
6 feet by 4 feet by 5 feet
SilcoTek processes orders in a variety of reactors depending on part geometry and volume.

10. Substrates Which Coat Well
300 and 400 grade stainless steel
High carbon steel
Titanium
Ceramics
Borosilicate glass
Inconel®
Hastelloy®
SilcoTek coats most common steel alloys, along with borosilicate glass.

11. Substrates with Issues
Nickel / Nickel plating
Aluminum*
Monel®
Copper
Brass
Gold and Silver plated components
Chrome Plated components
Magnesium
Elastomers
*heat-dependent
Pure nickel and copper cannot be coated. Copper alloys cannot be coated but Nickel alloys can be coated. Most aluminum alloys will soften when exposed to our process temperatures and are not recommended. Some applications using 6061 aluminum may be coated. Elastomers cannot be coated due to high process temperatures.

12. Corrosion Resistance of Coatings

13. Silcolloy™ Corrosion Resistance:
Stainless steel surfaces susceptible to attack from in chlorinated environments and acidic exhaust environments.
Corrosion resistant deposition is insoluble in hydrochloric acid and unaffected in salt water environments.
Silcolloy 1000 is a multi layer amorphous silicon coating designed to improve the corrosion resistance of steel or steel alloys. Silcolloy protects steel and stainless steel from chloride attack & is used in process, analytical and marine environments. Silcolloy is capable of withstanding temperatures up to 1000C making the coating an attractive option for customers looking for corrosion protection in high temperature environments.
Silcolloy is a cost effective way to extend the life of steel, stainless steel or exotic alloys; but is not intended to be an alloy substitute.
Because base metal attack can occur if the Silcolloy layer is compromised

14. Corrosion Resist studies
External Evaluation
Certified corrosion
engineers (Matco)
Spectroscopic
analysis
Mechanical testing
Electrochemical
Cyclic Polarization in neutral, acidic, alkaline
Atmospheric corrosion
ASTM moisture condensation
Salt spray ASTM B117
Stress corrosion cracking (MgCl2; ASTM G36)
SilcoTek partners with independent test laboratories to evaluate coating performance. Certified corrosion engineers, Matco Associates studied the corrosion performance of Silcolloy

15. ASTM G48 B Data: Pitting and Crevice Corrosion
ASTM G48 method B; Pitting and Crevice Corrosion
6% Ferric Chloride solution
72hrs, 20ºC
316L Stainless samples w/Gasket wrap
Sample
Initial
Weight (g)
Final
Weight
Loss (g)
Weight Loss
(g/m2)
Silcolloy™ Sample 17
0.0395 19
Silcolloy™ Sample 28
0.0513 25
Silcolloy™ Sample 47
0.0521
Bare Sample 27
9.5655
0.4789
231
Bare Sample 34
9.6923
0.4342
209
Bare Sample 37
9.6276
0.4731
228
Pitting and Crevice Corrosion tests show an order of magnitude reduction in corrosion weight loss when comparing 316L coated stainless steel coupons with uncoated coupons.

16. ASTM G48 B (cont.)
Bare 316L Stainless Steel coupon showing severe crevice corrosion
Uncoated coupon shows significant corrosion at gasket. Note deep pitting as well.

17. ASTM G48 B (cont.)
Corrosion resistant treated sample showing no crevice corrosion and slight pitting corrosion
Coated coupon shows only slight pitting and no gasket area damage.

18. ASTM G61 Data: Cyclic Polarization
ASTM G-61; Cyclic Polarization Electrochemical Corrosion Testing
Acid, neutral, basic aqueous solutions with varying Cl- ion concentrations (100, 3000, 5000ppm)
EG&G VersaStat System, 23ºC
316L vs. Silcolloy™ on 316L & 304L
-CR vs 316L Raw: 50x improvement
Ec = corrosion potential
Ic = current density at Ec
Eb = pitting potential
CR = corrosion rate
Neutral solution;
3000ppm Cl-
Sample
Ec, mV
Ic, uA/cm^2
Eb, mV
CR, mpy
316 L
-418
0.096
370
0.04
Silcolloy™ 316 L 
-533
0.002
1460
0.0009
304 L
-435
0.145
361
0.06
Electrochemical corrosion tests show a 50x improvement over 304 and 316ss coupons.

19. ASTM B117 Data: Salt Spray
ASTM B 117 – “Practice for Operating Salt Spray (Fog) Apparatus.”
4000 hour exposure
100 degree Fahrenheit
3.5% by weight sodium chloride
Reproduces exposure to marine environments.
4000 salt spray tests show some corrosion in uncoated coupon and no corrosion in coated coupon

20. ASTM B117 Data (cont.)
Silcolloy™ treated samples showed no signs of bleeding, rusting, or pitting corrosion

21. ASTM B117 Data (cont.)
The non-treated samples showed some light surface rusting, but no signs of pitting corrosion.
Some corrosion found at perforation in uncoated coupon

22. ASTM D4585 Data: Condensing Humidity
ASTM D 4585, “Practice for Testing the Water Resistance of Coatings Using Controlled Condensation.”
1000 hour study
100 degrees Fahrenheit
Distilled water
Reproduces exposure to atmospheric conditions
1000 hour humidity testing shows no adverse affects.

23. ASTM D4585 (cont.)
Silcolloy™ treated samples showed no signs of bleeding, rusting, or pitting corrosion

24. Silcolloy™ Advantages
Longer Life:
Extend lifetimes of equipment exposed to corrosive environments and/or process streams
Protection:
Protection of high value equipment in corrosive environments
Inert:
Provide enhanced corrosion resistance to analytical equipment while maintaining inert sample pathway
High Temperature:
High temperature stability up to 1000c
Silcolloy saves money by extending the life of process components. Customers may choose to Silcolloy coat stainless steel components and replace corroded components as needed over the life of the system rather than pay premium pricing for Hastelloy or other exotic alloys. Over the life of the system, a Silcolloy coated system will reduce costs by 60% when compared to a comparable Hastelloy system.

25. Silcolloy™ Applications
Manufacturing/Chemical
Process streams containing HCl
Environmental
Continuous Emissions Monitoring exposed to stack gases from coal fired plants and incinerators
Automotive
Equipment used in Automotive Exhaust testing and catalytic converter studies
Diesel EGR & Turbo systems
Marine
Some preliminary evaluation of coating in marine environments (offshore platforms)
The principal market application for Silcolloy is for hydrochloric acid or other chloride corrosives in manufacturing, chemical and petrochemical environments. High temperature, corrosive environments, such as stack monitoring systems, are also key application markets.

26. Conclusions/Future
Continual process improvement and new product development for coatings:
Improving the hardness of coatings
Improved corrosion resistant coatings
Hydrophobic surfaces for moisture sensitive applications
Protection of high nickel alloys such as Hastelloy® and Inconel®
Hydrogen embrittlement resistance.

27. QUESTIONS ?