Semi Coating Blog | Surface Science For Semi & PV Manufacturing

How to Prevent Filter Fouling and Reduce Filter Backpressure

Posted by Marty Higgins on Jun 15, 2018 8:59:00 AM

Process_stacks

Metal filters are critical to process and environmental quality.  Unfortunately in doing their job, filters capture particulates and eventually clog and foul.  Fouling can disrupt process fluid flow and can cause process shutdowns, here's how to reduce fouling and improve filter performance.  Oh and maybe save a lot of money!

 

In this blog post you will learn:

  • How silicon CVD coatings can change the surface energy, lubricity and fouling properties of a surface.
  • How coatings like Dursan and Notak can reduce filtration differential pressure.
  • How anti fouling coatings can extend the life of metal filters and prevent membrane fouling.

 How silicon coatings change the surface properties of metal filters.

Coated frit 3Coatings like Dursan and Notak™ are bonded to the surface of metal filters by a patented chemical vapor deposition process.  The coating gas penetrates the filter and creates a micro thin barrier coating throughout the filter area.  Even sintered metal frits can be treated.  The barrier coating bonds and penetrates into the surface creating a corrosion resistant, fouling resistant surface with high lubricity.  The sputter depth profile below highlights the silicon steel diffusion zone and bond to the stainless steel filter surface.  See how Dursan can solve your material problem.  

Dursan Composition-057151-edited

After processing, the filter will take on the surface properties of the coating, enhancing the corrosion resistance, fouling resistance, lubricity, surface energy/ hydrophobicity of the filter.  Read more about how our coatings prevent fouling.

 

Wear and friction data

Pin-on-disc comparison of Dursan (carboxysilane) to an oxidized stainless steel surface shows a 50% reduction in wear rate and a 35% reduction in coefficient of friction, improving the efficiency and wear resistance of the filter.  Read the complete study.

Dursan wear resistance 6 12 18

 

Carbon Coking Fouling Resistance

Coking and fouling studies show SilcoTek® coatings and coatings combined with a surfactant reduce fouling by 50% or more.  Reducing the particulate binding effect and making the filter easier to clean.   

coking heat sink fuels

Corrosion resistance

ASTM G31 immersion testing compared a Dursan coated surface with silicon and uncoated stainless steel.  The Dursan coated surface improved corrosion resistance by an order of magnitude, improving metal filter durability.  Get our latest on corrosion prevention, get our corrosion presentation.

Dursan_sulfuric_acid_corrosion

Surface energy

A key to particulate binding and fouling is surface energy management.  A low surface energy surface will reduce the particulate bond energy and make filter cleaning easier.  Surfaces like Notak™ (F-Dursan in the graph) offer the lowest surface energy and highest contact angle of any silicon surface tested.  The Notak surface reduces surface energy by 80% compared to stainless steel.  

Surface energy comparison

Read Moisture Resistance And Hydrophobicity Whitepapers

 

What's it all mean?  How Does a Low Friction Low Surface Energy Surface Prevent Membrane Fouling?

So what will a low surface energy high lubricity filter surface contribute to fouling prevention and improved filter performance?  Let's compare the differential pressure of an uncoated filter (graph below, top 2 lines) with a Dursan coated filter under simulated process conditions.  The coated filter (lower line) had nearly twice the life and half the differential pressure of the uncoated filter.*  That means that Dursan or other SilcoTek coatings can help extend the life of your metal filter while reducing energy loss and system back pressure.

Filter Differential Pressure vs. flow 6 11 18

Interested in fouling resistance?  Read our webinar presentation and learn about how our coatings reduce fouling in many applications.

Learn How To Manage Surface  Energy, Fouling, and Moisture Resistance

 

Coating benefits

heat exchanger foulingFouling reduction can benefit many applications including:

 

 

*Data courtesy of Porvair Filtration. 

Tags: Semiconductor

What's the Cost of a Corrosion Resistant Barrier Coating?

Posted by Marty Higgins on Jun 8, 2018 11:42:18 AM

corrosion-applications-graphic-271814-edited

What's the cost of a corrosion resistant coating?  Let's take a look at the real cost of buying and maintaining a corrosion resistant surface.  Hint, buying on the cheap may be the most expensive option. 

Corrosion is not simply a maintenance problem.  Corrosion can have a multitude of adverse effects like poor product yield, product contamination, damage to costly instrumentation, and low productivity.  To the extreme, corrosion can become a real drag on profitability.  According to US Government studies, corrosion costs the US $276+ billion annually, that's why there's a huge market in corrosion control.  But what's the true cost of implementing a corrosion solution?

In this blog you will learn:

  • How Dursan and Silcolloy corrosion resistant coatings perform compared to stainless steel and super alloys
  • Factors to consider when comparing corrosion resistant materials or coatings
  • Get a relative cost of various corrosion resistant materials
  • How life cycle costs can be a major factor in selecting a corrosion resistant material

First Consideration. Is The Corrosion Solution Effective? 

Before we discuss the true cost of a particular corrosion solution it's a good idea to be sure the material or coating in question are chemical resistant and effective in preventing or limiting corrosion.  Let's compare the effectiveness of corrosion resistant materials under various corrosive and temperature conditions. 

Get Our Latest Corrosion Solutions Presentation

The ASTM G31 immersion test (below) compares an uncoated 316L coupon with Silcolloy® and Dursan® coated coupons.  The coupons were immersed in a 20% HCl heated to 50 C.  After 7 hours the coupons were extracted, cleaned and weighed.  Corrosion rates where calculated based on weight loss.  The baseline corrosion solution, stainless steel, had a very high corrosion rate.  Use under similar conditions would require frequent maintenance and could potentially impact production if used in critical performance areas.  The Silcolloy coupon had significantly less corrosion but would likely require regular maintenance.  The Dursan coupon had about 1% of the corrosion rate compared to stainless steel, showing potential benefits to maintenance and operations cost.

HCl corrosion 50c exposure-496019-edited

Comparative ASTM G31 immersion testing in a sulfuric acid solution shows similar performance with the Dursan coated coupon performing exceptionally in the application with orders of magnitude reduction in corrosion rate.

Sulfuric acid G31 corrosion test-168851-edited

 

Here are images of the sulfuric acid test.  The uncoated 316L coupon (left) is significantly damaged by the sulfuric acid.  Additionally the acid solution is contaminated by the stainless steel, turning the fluid green.  The coated coupons remain undamaged and the sulfuric acid solution is not contaminated.  This could protect process fluids from contamination and improve yields.

Sulfuric acid G31 corrosion picture

Let's throw some superalloys into the mix and see how they perform.  In this comparison, we immersed coupons into 6M HCl for 24 hours and then measured the corrosion rate.  The superalloys, C276 and C22, performed the best, followed by the Dursan and Silcolloy coated coupons.  

Alloy_HCL_Corrosion_Comparison_2_10_26_15-158824-edited

We've compared the performance of various surfaces and found superalloys perform the best, followed by Dursan coated stainless steel, and finally stainless steel.  So the most cost effective corrosion solution are superalloys, right?  Well maybe yes and maybe no.  It all depends on the application.  Let's compare the cost of various corrosion resistant products.

How Much Vs. How Effective?  The Cost Benefit of Corrosion Resistant CVD Coatings.

First let's compare the cost of a valve manufactured using a superalloy, Dursan coated, and stainless steel.  The stainless steel valve is the cheapest, a fraction of the cost of Dursan or superalloy valve.  But remember the poor corrosion resistance of the stainless steel?  That poor performance could mean you'll be replacing that cheap valve 10 times during the useful life of the project or system.  That means the stainless steel valve is actually the most expensive at $370.00.  And that doesn't include the labor cost associated with replacing the valve and the lost productivity while the process or product is down.  Depending on application, the Dursan coated stainless steel valve offers a good mix of improved corrosion performance and cost.  For a 4x cost increase you get more than a 10X improvement in corrosion resistance.  The superalloy valve costs about 8x more but does not significantly improve corrosion performance over the Dursan valve (based on ASTM G31 tests).

Corrosion cost analysis Valve

Comparing the life cycle cost of operating a typical stack sampling system shows that after factoring in capital cost and component replacement cost; Silcolloy or Dursan coated stainless steel surfaces are the clear cost leader when compared to high performance alloys and untreated stainless steel.

 Silcolloy_Cost_Comparision_2_11_5_13-917513-edited

The Big Concern.  Picking The Best Corrosion Resistant Material For The Application 

Factors to consider when calculating the true cost of a particular corrosion solution include: 

  • The criticality of the application.  If you can't afford downtime or a corrosion failure may cost you a bundle, the superalloy may be good insurance against failure.
  • Length of service.  How long will the part be in service?  If the part is intended to be used for only a few weeks, a stainless steel component may perform just fine.  For intermediate duration or long term use Dursan or a high performance alloy may be a more appropriate and cost effective solution.
  • How sensitive is the process to contamination?  If corrosion particulates or ion contamination endangers product quality or yield, it may be ideal to coat the flow path regardless of duration of use.  For extreme sensitivity to metal ion contamination, coating a high performance alloy with Dursan or Silcolloy may be the most cost effective solution.  Dursan and Silcolloy do not contain metals, making a completely metal free and corrosion resistant surface. 
  • Ease of replacement.  How easy is the part to replace?  Ease of access may factor in selecting a cost effective corrosion solution.
  • Cost of part.  If the part is an expensive instrument probe, it would be highly cost effective to coat the part with Dursan.

It's clear that material cost is not the only factor when selecting a cost effective corrosion solution.  Weigh all factors carefully before committing to a corrosion resistant product.  Want to learn more about improving the corrosion resistance of your product at the fraction of the cost of superalloys?

 

Get Our Corrosion Webinar

 

Tags: Semiconductor

How to Prevent HBr Corrosion in Plasma Etch Applications

Posted by Marty Higgins on Jun 1, 2018 11:29:00 AM

Hydrobromic acid or hydrogen bromide (HBr) is commonly used in polysilicon etch applications and plasma etching.  It's an excellent etch compound but unfortunately it will also corrode delivery systems which can result in yield robbing ion contamination and increased maintenance cost. 

showerhead_2_2_19_16.jpgPreventing HBr corrosion can lead to the use of costly super alloys, but an alternative semiconductor approved material is available.  Silcolloy and Dursan silicon barrier coatings bonded to stainless steel flow paths offer the best of both worlds.  A durable and corrosion resistant surface and an inexpensive, workable stainless steel substrate.  In fact SilcoTek coatings, applied by CVD, can be bonded to existing components, no matter how intricate, and still maintain precision tolerances.

 

Get Our Latest Corrosion Solutions Presentation

Proven Results

ASTM G31 immersion testing demonstrates the superior corrosion resistance of Silcolloy and Dursan coated coupons.  After 264 hours of exposure in 48% (wt) HBr (hydrobromic acid) the SilcoTek coated coupons reduced the corrosion rate by up to 10X.  Uncoated stainless steel corroded at a significant rate while the Dursan coating corroded at a fractional 0.29 mills per year. 

hbr data graph.jpg

Visual inspection of the test coupons tell the story.  The uncoated stainless steel coupon shows moderate corrosion while the Dursan and Silcolloy coupons maintain their bright appearance.  

hbr data.jpg           

Want to watch our coatings in action?  Watch our corrosion video.

An inert corrosion resistant barrier silicon coating improves yield by preventing corrosive attack in semiconductor etch systems.  Get more information about how our coatings improve semiconductor performance.

Watch Our Semicon  Coatings Webinar

 

Tags: Semiconductor

Less Contamination and Improved Corrosion Resistance for Tanks

Posted by Marty Higgins on May 29, 2018 8:40:55 AM

Big-tank-coated-664703-edited

 

Did you know that SilcoTek can coat small process tanks and canisters with a high purity silicon coating? 

Our patented CVD coating process can apply non reactive and corrosion resistant silicon to stainless steel (or other metal alloy) canisters to both inside and outside surfaces.  Our micro thin silicon barrier coatings do not change the dimension or tolerance of the canister, allowing the customer to easily improve existing tank performance. 

Get Our Latest Corrosion Solutions Presentation

Improved tank inertness, purity and corrosion resistance

Test data show a silicon surface bonded to stainless steel can prevent interaction of the flow path material with the tank surface, preventing ion contamination, corrosion resistance and leaching of impurities into the process.

Read How To Set Up Your  Own Inertness Test

Inertness and purity

SilcoTek's Dursox coating (a silicon-oxide Dursan coating) protects your product from contamination because Dursox® contains no metals.  X-Ray photoelectron Spectroscopy (XPS) analysis (below) show no metallic contamination up to 10nm into the Dursox surface.  Assuring a contaminant free canister. 

High Purity Coatings presentation thumbnail

 

Canister Corrosion resistance

72 hour hydrochloric acid immersion testing show Dursox significantly improves corrosion resistance of tanks and containment vessels.  More importantly the process liquid (in this case hydrochloric acid) remained stable and was not contaminated by iron leaching or exposure to the stainless steel surface.  The beaker on the right shows a clear HCl liquid.  If the stainless steel were attacked by the HCl the liquid would have turned dark green.

Dursox_corrosion_Comparison_2_18_15 Dursox_HCl_imersion_10_08_15_

 

Dursox Silicon CVD coating applications

Fitok silconert coated sample cylinder

Dursox and other SilcoTek® coatings can be applied to a wide range of canister geometries:

 

 

  • Hydrogen peroxide in the ALD applications
  • HBr in etch applications
  • Acid cleaners
  • Shower heads
  • Storage tanks
  • Sample cylinders
  • Tubing, fitting and valve flow paths

 

Watch Our Semicon  Coatings Webinar

 

 

Tags: Semiconductor

How CVD Coatings Can Prevent Heat Exchanger Fouling

Posted by Dr. David Smith on May 18, 2018 10:06:21 AM

showerhead_2_2_19_16-640946-edited

Can SilcoTek® coatings prevent heat exchanger fouling deposit formation and coking in semiconductor process applications?  Read on and get some pretty impressive results!

Heat exchanger fouling and tube fouling can severely impact the performance of processes and instrumentation in just about every industry.  The effects of the accumulation of substances, be it binding of proteins in medical diagnostics or carbon particulates in aerospace, can have a range of impacts: 

Impact of fouling on semiconductor process systems.
  • Causes contamination
  • Reduces flow
  • Increases drag/pressure
  • Encourages corrosion
  • Increases emissions
  • Increases maintenance requirements
  • Slows production
  • Costs money!
heat exchanger fouling.png

 

A High Price 

Dealing with the impacts of deposits and build-up of unwanted materials depend on the application and importance of the process.  Regardless, the cost can be high.  Here are some examples of the impact of material build-up on critical surfaces:

  • Analytical
    • -Annual costs of false results in USA >$3 billion annually
  • Automotive
    • -10%+ increase in fuel consumption due to fouling
  • Refining
    • -$0.5 billion spent to overcome coking issues (2002)
  • Process heat exchangers
    • -50% of maintenance costs are caused by deposits, causing billions of dollars to industry.

 

Read our presentation on preventing coking and fouling

 

Potential Solutions

There are many possible solutions to the problem.  Some expensive, some not realistic, most are costly and can result in redesign or added maintenance.  Here are a few examples:

Solution Result
Increase energy / power / fuel consumption (basically brute force idea) Expensive and does not solve the problem
Control the incoming media that’s causing deposit build-up Rarely an option in industrial applications
Material selection Several options, difficult to optimize performance & cost
“Surface engineering” through advanced anti-fouling coatings 

Flexible and cost effective

Modify the existing part’s surface to make it behave how you need it to

 

The Benefits of Coatings to Prevent surface interaction

Coated frit 3.png Coated fittings.png Dursan_flanges-resized-600-774957-edited

 

Inert Coatings can be an effective solution for multiple applications and industries because they enhance the performance of the surface while preventing interaction of the base material with the interacting substance.  The result?  A better surface without changing the part design or physical property of the base material.  There are, however, several factors to consider when selecting the right coating for the application.  Such as:

-Do I have to re-engineer to account for tolerance changes?  In most cases no change in tolerance needed.  But consider for super high tolerance applications.

-Is there an environmental impact?  The amorphous silicon surface has very little environmental impact both during processing and as a product.

-Can the anti-coking coating withstand temperature, abrasion, corrosion, etc. in the application?  In many cases, yes but consult with a SilcoTek representative to be sure.

-How long will it last?  Depends on the application, but the coating should provide superior performance for years.  Contact a SilcoTek representative to discuss your application.

Want to learn more about our coatings and how they improve the performance of your product?  Get our webinar on demand.

Solving coking and fouling problems

How SilcoTek Coatings Prevent build-up

SilcoTek coatings act as an inert barrier, preventing catalytic or chemical interaction with the underlying surface.  For example nickel containing substrates catalytically form carbon deposits (coke) from petrochemical media. Causing build-up on the surface.  Coatings like SilcoKlean® or Dursan® bond to the surface and change the surface energy and inertness, preventing chemical adhesion and adsorption of the substrate.  The coating's low energy surface prevents the attachment of flow path chemicals to the surface.  Applications include:

SilcoTek Solutions & Applications    
     
Problem SilcoTek Coating Solution  
Carbon deposit, coke, formation from incomplete burning of fuel SilcoKlean barrier coating reduces catalytic coking and carbon deposit formation coking heat sink fuels.jpg
Bio-fouling in food applications.  Spores from sour milk suspensions stick to testing equipment Dursan prevents sticking by up to 76% Residue from sticking.png
Protein binding in medical diagnostics Dursan prevents surface interaction and sticking Protein_adsorption_graph-666998-edited.jpg
Carryover in GC & HPLC chromatography Dursan corrosion resistance prevents pitting & sticking to flow path surfaces Corrosion_Solutions_Dursan_Graph_10_16_13-118258-edited.jpg

SilcoTek offers many solutions to the problem of sticking, corrosion, deposits and carryover.  Go to our solutions page to learn more about our coatings.

 See How We Perform  In Your Application

 

 

 

Tags: Semiconductor

New Dursox CVD Coating For High Purity Corrosion Resistance

Posted by Marty Higgins on May 11, 2018 9:09:00 AM

Drusan flange 2 

 

Semiconductor manufacturers have found a new weapon in the struggle for improved yields, high purity corrosion resistance, and reduced cost.

 

Corrosives commonly used in semiconductor manufacturing cause yield robbing ion contamination; resulting in wafer contamination, higher maintenance and increased burn-in time. 

 

Dursox® is a thin but durable silicon oxide (SiO) high purity barrier coating that prevents semiconductor tool corrosion and erosion.  Our patented CVD coating process bonds Dursox to stainless steel and ceramic surfaces.  The micro-thin coating penetrates small holes, inner cavities, and narrow bore tubes without significant change in component tolerance. 

Find Out More About SilcoTek  Semiconductor Solutions

Watch our corrosion video and see how our coatings prevent corrosive attack.

Dursox®­ offers significant corrosion resistance when applied to stainless steel and other alloys; preventing contamination and extending component life.  See our semiconductor chemical compatibility list.

 

Dursox corrosion comparison 2 6 11 18

 

Dursox® is a high purity silicon oxide layer that contains no metals, assuring no leaching of metal ions into process streams.  XPS data show Dursox contains only silicon, oxygen and carbon, making it the ideal barrier coating for semiconductor manufacturing applications.

Dursox XPS Data 6 11 18

Dursox® is made for next generation semiconductor manufacturing systems.

Gas Delivery Systems Improved gas delivery system corrosion resistance
Etch Dursox high purity coating eliminates ion contamination in corrosive etch gas streams.
Atomic Layer Deposition (ALD) Dursox enhances purity by coating of all chambers and equipment. Reduces carryover and corrosion.
Ozone Stabilize flow path to assure ozone purity.
Gas Transfer Prevent ion contamination, assure high purity gases.
Chemical-Mechanical Planarization (CMP) Increase lubricity, prevent sticking and cut downtime.
Epitaxy Dursox significantly reduces contamination and maintenance caused by corrosion.

 

Dursox can be applied to most semiconductor tool components, including:

  • Showerheads
  • Supply tubes
  • Fittings
  • Regulators
  • Reactors
Semiconductor_image.jpg

Learn more about Dursox® and SilcoTek® coatings for semiconductor applications.

Watch Our Semicon  Coatings Webinar

Tags: Semiconductor

New Superhydrophobic Coating Notak Improves Moisture Resistance

Posted by Marty Higgins on May 4, 2018 9:07:18 AM

Hydrophobic surface drops.jpg

How to improve high temperature hydrophobicity and oleophobicity in demanding fuel injector and combustion applications?  SilcoTek® answered the challenge by developing a new high temperature moisture and oil repelling coating able to remain stable at temperatures of 300c and higher. 

In this blog post you will learn:

  • How SilcoTek's new Notak™ coating impacts surface energy, hydrophobicity, oleophobicity and fouling resistance
  • How surface energy changes moisture resistance
  • The benefits of a hydrophobic coating surface
  • The benefits of on oleophobic coating surface

 

SilcoTek's new coating, Notak, achieved significant improvement in hydrophobicity and oleophobicity compared to the uncoated DLC surface.  More impressively, the new coating remained stable when exposed to high temperatures for over 24 hours.  Both hydrophobicity and oleophobicity contact angle were unchanged over the test period, indicating stable surface energy.  

New Coating Hydrophobic and Oleophobic

SilcoTek® coatings are the ideal hydrophobic and oleophobic solution to challenging environments.  Applications include:

oil-refinery-day

- Analytical sampling
- Refining/petrochemical
- Oil and Gas exploration and transport
- Automotive
- Aerospace
- Heat exchangers 
- Process sampling

 

 

 

You can get lots of interesting information on how to prevent fouling and manage moisture resistance by viewing our webinar "Solving Surface Fouling with New Non-Stick CVD Coatings".

Solving coking and fouling problems

SilcoTek's inert, high durability, high tolerance coatings can be applied to high precision components used in the most demanding environments:

anticoking_whitepaper
  • Fuel injectors
  • Nozzles
  • Probes
  • Separators
  • Downhole tools

 


Learn more about SilcoTek hydrophobic coatings

 

About Hydrohobicity a Comparison

A hydrophobic surface is a water repelling, low surface energy surface that resists wetting.  Moisture contact angle measurements will classify a surface as hydrophobic when the contact angle of the water droplet exceeds 90 degrees.  Exceed the 150 degree contact angle mark and the surface will be classified as a superhydrophobic coating.  Water will jump right off the surface as seen in this video.

There are many benefits of a moisture repelling surface.  They include:

- Surface icing prevention - Condenser & evaporator fouling prevention
- Improved corrosion resistance - Prevent moisture contamination in heat trace tubing 
- Produced water filtration & management - Improved reliability in continuous emissions monitors (CEMS)
- Improved moisture detection instrumentation - HPLC medical diagnostics improved separation & corrosion resistance
- Manage moisture contamination in liquid natural gas systems - Prevent contamination in analytical sample transfer systems

 

How do I get a surface to match my desired moisture level of moisture resistance?

You don't have to make a super radical change to material or product construction in order to change the moisture performance.  Fortunately we offer silicon barrier coatings with a wide range of water management capabilities.  Want a more corrosion resistant or inert coating with a low surface contact angle?  Try SilcoNert® 1000 or Silcolloy®.  If you're looking for an inert coating that's not too moisture repelling, go with SilcoNert® 2000.  Need maximum water repelling coating properties?  Dursan® or our new Notak coating may do the trick.  Note, our Notak coating is in pre-production Beta testing so we have limited capacity for that coating.  Contact our Technical Service Team to discuss your application and we'll be happy to make a coating recommendation. 

contact angle comparison 4 4 18

 

The comparative graph above highlights the water repelling properties of each of our coatings compared to stainless steel; each coating has specific applications and benefits.  Go to our applications guide to get the lowdown on each of our coatings.

Get our coating application and properties guide.

 

Hydrophilic Surfaces

Not to be outdone, hydrophilic surfaces have benefits as well.  What are hydrophilic surfaces?  They are high surface energy substrates that attract water and allow wetting of the surface.  They typically have a droplet contact angle measurement of less than 90 degrees.  Lots of surfaces tend to be more water friendly including, glass, steel, or stainless steel and many coatings and paints.  Of course test results can depend on the surface roughness and surface energy of the material you're testing.

Learn How To Improve Moisture Resistance, Fouling Resistance, and Corrosion Resistance.   Get Our Presentation.

 

Benefits of a moisture friendly surface include.

- Improved separation in medical diagnostics (application dependent) - Improved efficiency in heat transfer devices & heat exchangers
- Improve acceptance of In-body devices - Improve surface interaction in filtration devices (application dependent)

 

Low surface tension liquids like oil or organic solvents are designed to wet the surface for maximum lubrication or solvation.  But what if you're separating organics or don't want the surface to wet?  Water repelling materials like PTFE aren't effective in repelling oil.  Here's what oil and hexadecane look like when placed on a PTFE surface.

Hexadecane on teflon 29.7 degree contact angle-401247-edited.png oil on teflon 48.5 degree contact angle-515333-edited.png

We bonded our new Notak coating on a rough stainless steel surface to see if the contact angle would increase.  Notak made a big difference in contact angle, making the stainless steel oleophobic surface.

hexadecane on rough fluoro 92.6 degree-142340-edited-531970-edited oil on rough fluoro 95.5 degree-075556-edited-682056-edited

Given the nature of refining or cleaning processes for that matter, we can expect the surface to be exposed to elevated temperatures.  PTFE is high temperature limited and can fail in many high temperature applications.  We exposed the Notak surface to elevated temperature (300°C) for several hours to gauge the impact to wettability, high temperature oleophobicity, and contact angle on various surfaces.  The graph below shows consistent contact angle readings over the 90+ hour test.  PTFE would have failed at 250°C. 

Oxidative stability, oleophobicity fluoro surface.pngThe contribution of surface energy and it's relationship to process fluids can have far ranging impacts.  Surface interaction can impact corrosion, fouling, analytical sampling results, filtration and medical device performance.  So it's important to understand how to manage the energy of critical flow path surfaces.

Get some really informative and helpful tips on ways to prevent fouling, change surface energy, & improve surface performance.

Learn How To Manage Surface  Energy, Fouling, and Moisture Resistance

 

Tags: Semiconductor

How to Test a High Purity Coating For Reactivity and Adsorption

Posted by Marty Higgins on Apr 27, 2018 11:01:54 AM

inert-sampling-applications-graphic.jpg

Customers interested in improving instrument sensitivity and precision often evaluate the coating surface for reactivity to confirm the coating meets performance parameters.  But what's the most effective way to test a coating for inertness and purity?  Let's find out.

Testing and evaluating a high purity coating or surface for adsorption, non reactivity, inertness and purity can be a challenging undertaking, especially when testing reactive compounds at trace levels.  If you're having trouble figuring out how to evaluate a coating, you're in luck!  We've got 30 years of experience recommending processes or methods to use when evaluating an inert coating or surface.  Here are a few tips we've learned over the years.

In this blog you will learn:

- Tips on how to evaluate a surface for chemical inertness and reactivity

- How selection of test compounds and concentration affect results

- Get sources for inertness test design standards and specifications

- Get ideas on test system design

Selecting The Compound & Concentration to Test for Semiconductor Process Contamination

How do I know a surface is inert for my test?  That's a tough question to answer.  A surface may perform very well for one compound but not for others.  Additionally, a surface may be adequate for higher levels of concentration but not for trace analysis or speciation.  Let's first discuss compound selection, then we'll expand the discussion to concentration.

Selecting the compound

If you have one compound and don't expect to test other reactive chemicals then picking a compound to test is pretty straight forward; just pick that chemical at the expected concentration and run the test.  Of course you'll need to run a statistically significant number of runs (say n=5) and test a few coated flow path component samples to assure repeatability, but overall a pretty easy method to evaluate inert surfaces.  Before testing it's always a good idea to understand the capabilities of the coating or surface.  Here's information on our coatings:

Go To Our Coating Material Property & Specifications Page

Unfortunately most analytical systems will be exposed to several active compounds over the life of the flow path.  In this case things can get complex quickly.  Unfortunately you can't test all reactive compounds, there are millions of chemicals out there so testing them all would take just a few minutes short of forever.  Rather than spending the rest of your life evaluating various flow path surfaces, consider testing a class of reactive compounds rather than all potential analytes.  For example, endrin and DDT are excellent environmental test compounds because they rapidly degrade when in contact with a reactive surface, especially if it's a hot surface. 

Chromatography companies offer good reference source material for selecting chemical standards containing target compounds for your analysis and surface needs, be it environmental testing, clean air standards, whole air monitoring standards or oil and gas sampling.  The standard can be sourced from several companies that offer calibration samples.  If you're testing lots of compounds the standard can get expensive pretty quickly so be judicious in your selection. 

Here are a few links to relevant company information on sourcing chemical standards.

sample_cylinders_group_tomarty-588616-edited

 

Concentration matters

OK I've selected my test compounds, is that it?  Sorry no.  You'll need to select the compound concentration.  In many ways concentration is as important as the test compound.  Take sulfur analysis for example.  A stainless steel surface may yield perfectly fine results at percent level analysis but sample at part per million levels and it's a completely different story. 

Sulfur is known to adsorb or "stick" to stainless, glass or ceramic flow paths.  But flow enough high concentration sulfur through the flow path and the active surface will be seasoned or primed to the extent that tests will yield reasonably good results.  However at ppm or lower levels, sulfur will be adsorbed onto the surface because there's not enough of the analyte to adequately "prime" all the active sites.  So virtually all the sample is lost.  Here's a chart comparing the loss rate of trace H2S.  You can see that virtually all H2S is lost within an hour of exposure.  The SilcoNert® coated surface adsorbs virtually no sulfur compound.

H2S_Comparison_72_hr_11_21_13

Factors to consider when selecting concentration include:

  • Regulatory requirements
  • Industry or customer standards
  • ASTM recommended methods
  • Internal specifications

Setting a lower concentration limit to use for a coating evaluation may depend on the lower calibration point for the instrument or system.  To establish that baseline, find any relevant regulatory or industry standards that dictate a calibration sample range.  Often you'll need to test a system for levels lower and higher than the established range of operation.  So for example a calibration run for a flare CEMS may require a total sulfur sample be run at a low side of 5ppm and a high range of 200 ppm for an operation range of 10 to 150ppm.  The high range sample may be relatively easy to achieve but all sorts of gremlins can pop up when dealing with a 5ppm sample.  Some factors to consider when testing at low levels include:

  • Faster expiration of the standard or stability of the chemical standard
  • Contamination and cross contamination
  • Adsorption by an uncoated reactive fitting or fritted filter
  • Seal material like o-rings that may be reactive
  • Moisture contamination may cause adsorption
  • Corrosion related particulate adsorption
  • Seams or pinholes that promote cross contamination or trace sample loss
  • Cleanliness of the system
  • System surface temperature, phase change
  • Detector or instrument sensitivity to the target compound

The details make a big difference when testing reactive samples at low levels.  Take note system parameters and any changes made during the test to assure an apples to apples comparison and to avoid "getting lost in changes" while troubleshooting a system.   

Get 7 Tips For Improved   Analytical Sampling

System Design, Testing an Inert Coating

Test system example 4 25 18

 So you're all ready to go!  You've got the samples at the right concentration, you've got the test method (or ideas of a method) based on industry, regulatory or company procedures.  But what about the test system itself?  Here are a few ideas to be sure you get reliable, accurate test results.*

The test system may be set up in accordance with regulatory or industry practices; when evaluating a surface always take into consideration the following: 

  • Apples to apples.  Don't change the test conditions during the evaluation
  • Nooks and crannies.  Minimize surface pin holes, threads grooves or other areas where a sample can get trapped and cross contaminate a test. 
  • Combining reactive surfaces with inert surfaces.  You can't test an inert surface by placing it in line with a reactive surface.  For trace analysis the sample will be adsorbed by the reactive areas so a comparison of surfaces would yield the same results.  You'll need to either coat the entire test flow path and compare 2 competing flow paths or select a known inert surface and change only a portion of the flow path for comparison.
  • Minimize flow path complexity.  Keep the test flow path as simple as possible to minimize test variables.
  • Make the exposure time adequate to determine effectiveness.  Either flow through a long tube at low flow or through a high surface area component like a sintered metal frit to be sure there's adequate surface exposure.  Another option would be to test by residence time in a sample cylinder.  This method can take a while (days or weeks) but will allow you to establish the degradation rate of the sample.  To accelerate the test, consider heating the sample cylinder to accelerate the reaction rate.  Here's an example of 15 day comparative testing for sulfur adsorption.  The top chromatographs continue to show sulfur peaks after 15 days for SilcoNert® (Sulfinert®) coated sample cylinders.   Uncoated stainless steel sample cylinders adsorb the sulfur (lower graphs).**
15 day sulfur adsorption test  
  • Seals.  Viton, septa or other seal surfaces can be active.  Minimize the use of polymeric seals to limit adsorption.
  • Instrument capability.  If your instrument is not capable of testing to the desired concentration or is not set up to yield reliable results for a target compound then don't bother evaluating the surface.  Instrument factors to consider are:
    • Detector (designed for the target compound)
    • Appropriate instrument (LC or GC?)  Should be capable of testing in the target sensitivity range for those compounds.
    • Calibration.  Instrument should be calibrated and maintained 
    • Training.  The analyst should be familiar with the instrument and detector.

Take a short cut

Are there papers available comparing surfaces for inertness for your sample?  You bet!  SilcoTek has a considerable library of comparative whitepapers demonstrating the effectiveness of our coatings in inertness applications.  We don't want you to take our word for it, or rely on someone else's test for your application, but reading papers that discuss testing a coating in a particular application can be helpful in getting evaluation ideas or understanding the limitations of a surface.

Want more information? Read industry whitepapers

 *Image courtesy of Restek® Corp.

* *Data courtesy of Restek® Corp.

Tags: Semiconductor

How to Stop Heat Exchanger Fouling and Tube Fouling

Posted by Marty Higgins on Apr 20, 2018 12:39:54 PM

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Can SilcoTek coatings prevent deposit formation and coking in analytical and process applications?  Read on and get some pretty impressive results!

Heat exchanger fouling and tube fouling can severely impact the performance of processes and instrumentation in just about every industry.  The effects of the accumulation of substances, be it binding of proteins in medical diagnostics or carbon particulates in aerospace, can have a range of impacts: 

  • Increase weight
  • Causes contamination
  • Reduces flow
  • Increases drag
  • Encourages corrosion
  • Increases emissions
  • Increases maintenance requirements
  • Creates false results
  • Costs money!
heat exchanger fouling.png

Learn How To Manage Surface  Energy, Fouling, and Moisture Resistance 

A High Price 

Dealing with the impacts of deposits and build-up of unwanted materials depend on the application and importance of the process.  Regardless, the cost can be high.  Here are some examples of the impact of material build-up on critical surfaces:

  • Medical / bio analytical
    • -Annual costs of false results in USA >$3 billion annually
  • Automotive
    • -10%+ increase in fuel consumption due to fouling
  • Refining
    • -$0.5 billion spent to overcome coking issues (2002)
  • Heat exchangers in semiconductor and other applications
    • -50% of maintenance costs are caused by deposits, causing billions of dollars to industry.

 

Read our presentation on preventing coking and fouling

 

Potential Solutions

There are many possible solutions to the problem.  Some expensive, some not realistic, most are costly and can result in redesign or added maintenance.  Here are a few examples:

Solution Result
Increase energy / power / fuel consumption (basically brute force idea) Expensive and does not solve the problem
Control the incoming media that’s causing deposit build-up Rarely an option in industrial applications
Material selection Several options, difficult to optimize performance & cost
“Surface engineering” through advanced anti-fouling coatings 

Flexible and cost effective

Modify the existing part’s surface to make it behave how you need it to

 

The Benefits of Coatings to Prevent surface interaction and stop heat exchanger fouling

 

Coated frit 3.png Coated fittings.png HPLC column 8.png

 

Inert Coatings can be an effective solution for multiple applications and industries because they enhance the performance of the surface while preventing interaction of the base material with the interacting substance.  The result?  A better surface without changing the part design or physical property of the base material.  There are, however, several factors to consider when selecting the right coating for the application.  Such as:

-Do I have to re-engineer to account for tolerance changes?  In most cases no change in tolerance needed.  But consider for super high tolerance applications.

-Is there an environmental impact?  The amorphous silicon surface has very little environmental impact both during processing and as a product.

-Can the anti-coking coating withstand temperature, abrasion, corrosion, etc. in the application?  In many cases, yes but consult with a SilcoTek representative to be sure.

-How long will it last?  Depends on the application, but the coating should provide superior performance for years.  Contact a SilcoTek representative to discuss your application.

Want to learn more about our coatings and how they improve the performance of your product?  Get our webinar on demand.

Solving coking and fouling problems

How SilcoTek Coatings Prevent build-up

SilcoTek coatings act as an inert barrier, preventing catalytic or chemical interaction with the underlying surface.  For example nickel containing substrates catalytically form carbon deposits (coke) from petrochemical media. Causing build-up on the surface.  Coatings like SilcoKlean® or Dursan® bond to the surface and change the surface energy and inertness, preventing chemical adhesion and adsorption of the substrate.  The coating's low energy surface prevents the attachment of flow path chemicals to the surface.  

Applications include:

 

SilcoTek Solutions & Applications    
     
Problem SilcoTek Coating Solution  
Carbon deposit, coke, formation from incomplete burning of fuel SilcoKlean barrier coating reduces catalytic coking and carbon deposit formation coking heat sink fuels.jpg
Bio-fouling in food applications.  Spores from sour milk suspensions stick to testing equipment Dursan prevents sticking by up to 76% Residue from sticking.png
Protein binding in medical diagnostics Dursan prevents surface interaction and sticking Protein_adsorption_graph-666998-edited.jpg
Carryover in GC & HPLC chromatography Dursan corrosion resistance prevents pitting & sticking to flow path surfaces Corrosion_Solutions_Dursan_Graph_10_16_13-118258-edited.jpg

 

SilcoTek offers many solutions to the problem of sticking, corrosion, deposits and carryover.  Go to our solutions page to learn more about our coatings.

 See How We Perform  In Your Application

 

Tags: Semiconductor

Where to Buy High Purity Silicon Coated Products For Semiconductor

Posted by Marty Higgins on Apr 13, 2018 8:47:00 AM

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Did you know that you can buy SilcoTek CVD high purity silicon coated products directly from the manufacturer?  Do you care?  Well you should because it could save you time and money in the long run.

Our network of Approved Partners offer SilcoTek® coated products directly off the shelf to help simplify your supply chain.  We don't sell finished products (only coating services), so we work with leading OEMs and re-sellers to make the purchasing process easier for you.  Now you can get the benefits of high purity silicon barrier coatings without the hassle!

In this blog post you will learn how buying SilcoTek CVD coatings through OEM manufacturers can benefit your supply chain:

  • Save time - place one order with your supplier and let us handle the rest
  • Lower costs - save on shipping and product disassembly/assembly
  • Simplify logistics - eliminate the need to manage multiple POs and vendors

View OEM Partner Directory

Lots of customers send in parts for CVD coating application.  Our manufacturing lead time averages about 5 business days for most coatings.  We're fast and offer a great product but there is one drawback.  Parts need to be disassembled before sending them to SilcoTek for coating service. 

single-stage_regulator_cross_sectionWhy do I have to disassemble parts? 

In order to coat a part, the surface must be exposed to our coating gases.  We don't need much space (we can penetrate and coat a sintered metal frit for example) but we do need some space.  Areas that are not exposed, like seals or internals of assembled parts may not get a consistent exposure to our process gases.  Surfaces also can't be inspected or adequately prepared for coating so there's a risk of inadequate coating.  As we noted before lots of customers send in their disassembled parts but others really don't want the headache.  It's one thing to take a fitting apart but it's can get sketchy for a novice to take apart a valve or a regulator.  Then there's the time factor.  Some companies or individuals have the resources and knowledge to assemble and disassemble parts but others have to either become fast learners or must pay to have someone properly assemble the part.  That's where our OEM Partner program comes in handy.

 

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No More Assembly

We've partnered with some of the best manufacturers in the industry to offer SilcoTek® coated products.  They recognize our coatings are the best in the industry and want to improve the performance of their products (here are just a few case studies for example).  Our coatings offer an additional dimension in performance, be it high purity, corrosion resistance, non-stick, or moisture resistance.  For the customer it means you don't have to take the time and effort to send in parts, just order them already coated from the manufacturer!  What can I buy?  Lots of things.  Here's list of components you can get directly from the OEM manufacturer. 

  • Fittings & Valves
  • Sample Cylinders
  • Process Sample Probes
  • Regulators & Flow Control
  • Filters & Separation
  • SST Tube, Tubing & Heat Trace
  • OEM & Instrumentation

 

The Cost

Just do a Google search on the cost of placing and processing a PO and you'll see a wide range of estimates.  PO costs can range from about $60 per order to over $700 depending on industry.  That's just the administrative cost associated with order processing.  Now add in the handling cost at shipping and receiving and you're talking a fair amount of money invested in sending in a part for coating.  That's why it's worth a look into specifying our coatings when purchasing parts from the component or equipment manufacturer.  Depending on the OEM stock situation, the lead time may or may not be longer but from a cost perspective it'll be worth it to add our coating when specifying and purchasing the part.  Are you an OEM?  Become a partner and improve your products.

Become a Partner

The logistics

From a logistics and SKU perspective it also makes sense to consider purchasing coated parts.  A typical purchasing cycle can entail the following:

  • Specify coating
  • Source uncoated part or component.
  • Disassemble part
  • Place coating PO
  • Ship part to SilcoTek
  • Status order
  • Receive coated part from SilcoTek
  • Reassemble part
  • Process invoice

With good planning, the entire purchasing cycle can be eliminated by specifying our coating when placing an order for the uncoated part at the OEM level.  That will go a long way toward getting home a little earlier from work or greatly reduce the complexity of the order process!

Click here to go to our OEM partner directory.  The directory will take you to specific products and vendor purchasing information.

Want something that's not on our list?  Contact us and we'll do our best to work with your vendor to get us added as an option.

 

 

Tags: Semiconductor