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FEBRUARY 2011 • VOL 6 • ISSUE 1

THE OFFICIAL NEWSLETTER OF THE ASM THERMAL SPRAY SOCIETY

INTERNATIONAL THERMAL SPRAY & SURFACE ENGINEERING

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JTST Highlights

Society News

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FEBRUARY 2011 • VOL 6 • ISSUE 1

iTSSeINTERNATIONAL THERMAL SPRAY & SURFACE ENGINEERING

THE OFFICIAL NEWSLETTER OF THE ASM THERMAL SPRAY SOCIETY

ADVANCED MATERIALS & PROCESSES • FEBRUARY 2011 29

EEditors Robert Gansert William Jarosinski

Co-Managing Editors Ed KubelJulie Kalista

Art Director Barbara L. BrodyProduction Manager Joanne MillerPublisher Joe Zion

National Account ManagerKelly Thomas, CEM.CMPMaterials Park, Ohiotel: 440/338-1733 e-mail: [email protected]

Thermal Spray Society Executive Committee

Charles M. Kay, President

Mitchell Dorfman, Immediate Past President

Luc Pouliot, Vice President

Douglas G. Puerta, Secretary/Treasurer

Randall S. Barnes, Executive Director

International Thermal Spray & Surface EngineeringTM

is published quarterly by ASM International®, 9639 Kinsman Road, Materials Park, OH 44073; tel: 440/338-5151; www.asminternational.org. Vol. 6, No. 1. Copyright© 2011 by ASM International®. All rights reserved.

The acceptance and publication of manuscripts in International Thermal Spray & Surface Engineeringdoes not imply that the editors or ASM International®

accept, approve, or endorse the data, opinions, andconclusions of the authors. Although manuscripts published in International Thermal Spray & Surface Engineering are intended to have archival significance,author’s data and interpretations are frequently insufficient to be directly translatable to specific design,production, testing, or performance applications without independent examination and verification of their applicability and suitability by professionallyqualified personnel.

5 Development of Nanostructured Coatings for Enhanced Corrosion Performance

7 Materials Testing for use in Strong H2S Acidizing Environments

10 Application Note: Corrosion Resistant, Non-slip Thermal Spray Coating for Harsh Industrial Environments

Departments2 Message from the TSS President

3 ASM Thermal Spray Society News

12 JTST Highlights

Editorial Opportunities for iTSSe in 2011The editorial focus for iTSSe in 2011 reflects established applicationsof thermal spray technology such as corrosion and transportation, aswell as new applications representing new opportunities for coatingsand surface engineering.

May Applications in the Transportation Industry

August Emerging Technologies

November Energy Production Applications

To contribute an article to one of these issues, please contact the editors c/o Julie Kalista at [email protected]. To advertise, please contact Kelly Thomas, [email protected].

About the coverSHS8000 twin wire arc-spray coating applied to a combustor water wallin a biomass boiler for elevated temperature corrosion erosion protection.Photo by B. Merkle from The NanoSteel Company.www.nanosteelco.com

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ADVANCED MATERIALS & PROCESSES • FEBRUARY 201130

M any of us tend to skip over the editorial in a magazine and to go to the parts of the magazine that offersomething of interest. However, there is a lot of information of particular interest in this message that

stems from the creativity of TSS Volunteers to provide a diverse international slate of offerings in promotingsurfacing technologies.

Mark Your Calendar for:

The International Thermal Spray Conference—ITSC 2011—in Hamburg, Germany, on September 27-29,2011. Highlights of this event include uniting eight national and international Conferences and Research

Colloquiums under one roof as part of the DVS Congress 2011.

ITSC 2012 in Houston, Tex., on May 21-14, 2012. This event will include an International University Showcase withpresentations by leading professors highlighting programs, students, facilities, and projects. It is anticipated that theProgram will include an extensive culmination of Thermal Spray Applications.

TSS Committee Highlights: Certified Thermal Spray Operator (CTSO)—Certification Test Centers are being estab-lished around the world based on the international response for this new certification program. Detailed informationis on the TSS Website (tss.asminternational.org).

TSS Collaborations:• TSS has accepted the gracious invitation to become a “Supporting Member” of the Japan Thermal Spray Society

(JTSS).• TSS and European Thermal Spray Association

(ETSA) will be working together to promote activities to each other’s members.

• The valued relationship between TSS and German Welding Society (DVS) is expected to create joint efforts for successful International Thermal Spray Conferences and joint efforts to promote and support Thermal Spray activities around the world.

Please see the TSS Website(tss.asminternational.org) for a complete list of international associations and activities.

Charles M. Kay, president, Thermal Spray Society

TSS Volunteers ‘Chemistry’ works well

Nominations sought for ASMThermal Spray Society BoardThe ASM TSS Nominating Committee is currently seeking

nominations to fill two director positions on the ASM ThermalSpray Society Board. The Nominating committee is partic-ularly seeking nominees from the user community, but nom-inations are solicited from all segments of the thermal spraycommunity.

Nominees must be a member of the ASM Thermal SpraySociety and must be endorsed by five TSS members. Boardmembers whose terms are expiring may be eligible for nom-ination and possible re-election on an equal basis with anyother nominee. Nominations must be received no later thanApril 1, 2011.

A nomination form can be obtained via the ASM TSS web-site at http://tss.asminternational.org. For more information,please contact Sarina Pastoric at [email protected].

[email protected]

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TSS seeks student board member applications

TSS is pleased to announce the continuation of the TSS StudentBoard Member Program, and is looking for members because itvalues the input and participation of students and is looking fortheir insights and ideas. Students do not need to be a member ofASM or TSS.

For more information on the eligibility and benefits of being astudent board member, visit asminternational.org and scroll thoughthe ‘Did You Know’ box till you see ‘Student Board Members.’Click on the link to learn more. The deadline to submit an applica-tion is April 1, 2011.

ITSC 2011 in Hanseatic City of Hamburg

The International ThermalSpray Conference 2011 will beheld September 27-29, 2011, atthe Congress Center Hamburg,Germany. The event will bepart of the DVS Congress andExpo 2011, an interdisciplinary event addressing the areas of join-ing, cutting, and coating technology. ITSC 2011 is cosponsored bythe German Welding Society (DVS), the ASM Thermal Spray So-ciety (TSS), and the International Institute of Welding (IIW), andoffers the opportunity for exchange of expertise and knowledge inthermal spray research, equipment, and applications. The event

theme of “DifferentDays, Different Mar-kets,” fits nicely withthe strategic goal ofthe thermal spraycommunity to iden-tify and addressnovel applicationsand new users forthermal spray coat-

ings. To reinforce the position of thermal spray in its existing andfuture markets, ITSC 2011 offers a very practically oriented “ap-plication highlights,” as part of its technical program. Papers are in-vited in the areas of:

• Thermal Spray Processes• Properties• Equipment and Consumables• Applications• Economic, Regulatory, and Other Business Issues• Young Scientists

CTSO Certification UpdateHow do you earn a CTSO? Right

now you should sign up to take the cer-tification exams during the pilot testphase, which is scheduled to end early in March of 2011. The costfor early adopters is less because feedback is needed on exam ques-tions to determine the passing score and final form of the exam.

progressivesurface.com

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So if you hate exams, now is a good time to take it: your feedbackmight mean that some questions are eliminated!

The pilot program has a limited time line because the examsneed to be completed to fully administer the program. The finalprogram will consist of three exams: a general knowledge of ther-mal spray fundamentals exam, and specific thermal spray processexams; one will be a short, multiple choice exam with questions re-lated to the process and the other will be a practical exam whereyou will use the process and submit a thermally sprayed coupon toa third party lab for testing.

More information on the program can be found on the TSS web-

site at http://tss.asminternational.org/portal/site/tss/Certification/. For more information, visit the certification section of the TSS

web site at http://asmcommunity.asminternational.org/portal/site/tss/Certification/ or contact Louise Wehrle, Ph.D., CAE at [email protected] or 440/338-5151, ext. 5894.

Education Course: Thermal Spray TechnologiesMarch 24-25, 2011 Instructor: Chris C. Berndt, PhD, FASM Location: Chicago, Ill., USA

This course provides a thoroughgrounding and understanding of thermalspray processes, depicts the complex sci-entific concepts in terms of simple phys-ical models, and integrates thisknowledge to practical engineering ap-plications and commonly accepted ther-mal spray practices. Participants areencouraged to contact the instructor(s)prior to the course so that any particularapplication or problem may be addressed as a case history or ex-emplar. Participants receive the Handbook of Thermal Spray Tech-nology as part of the registration fee. To register, visitwww.asminternational.org/education.

Want to reach the Thermal Spray industry? Make the iTSSe newsletter (print), TSS eNewsletter, and ASM Thermal Spray online products a part of your integrated marketing campaign.

Target your customers with ASM/TSS online marketing solutions. www.asminternational.org/access

Wear and Corrosion Event 2010was a huge success!

The Practical Solutions for Wear and Corrosion Problemsevent was cosponsored by ASM Thermal Spray Society andNACE International, and took place November 8-10, 2010, inSão Paulo, Brazil. Over 180 people attended this first everSouth American event that featured opening remarks by Roge-rio Lima, National Research Council of Canada; André O’Cz-erny, Sulzer Metco, USA; and Tom Weber, Trenton Corp.,USA. There were 10 sessions that included multiple presen-tations throughout the three-day conference. The event con-cluded with a TSS/NACE discussion panel.

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Corrosion is an electrochemical process that occursgenerally at the surfaces of metals and often initiatesat the sites of chemical or physical defects. Several

publications[1-3] show the superior resistance of metallicglasses and/or nanocrystalline materials to electrochemicalattack due to the difficulty of the system to set up specificanodic and cathodic sites as the microstructural scale is re-duced. Nanocrystalline materials according to the ASTME2456-06 “Terminology for Nanotechnology” havegrain/phase sizes less than 100 nm while metallic glasses arehave atomic level length scale, which can extend up to a cou-ple of nanometers, and, thus, represent the ultimate level ofmicrostructural uniformity.

Thermal spray coating processes deposit feedstock mate-rial either in a molten or semimolten condition to form a coat-ing by building up successive layers. Thermal spray offers acommercially viable route to produce refined-length scalesdue to the high cooling rates of individual splats making upthe coating. However, rapid solidification alone will only re-duce grain/phase sizes to the microscale since growth is rapidonce nucleation is initiated. Further refinement of the coatingstructure to the nanoscale level can only be achieved throughprocessing specialized glass forming compositions, whichresist nucleation upon solidification. The key is to design spe-cific alloy compositions that exhibit critical cooling rates formetallic glass formation below the average cooling rate ofthe application process. Case studies are presented that show

examples of nanolength scale achieved in thermal spray coat-ings and some of their benefits in improving performance inharsh corrosion environments.

HVOF Coatings for Seawater ApplicationsIn high-corrosion environments such as seawater applica-

tions, maintaining a completely amorphous structure is para-mount to maximizing corrosion performance. A solution forthis environment is NanoSteel’s SAM2X5 alloy appliedusing the high velocity oxy-fuel (HVOF) process, which hasbeen extensively studied in the High Performance CorrosionResistance Materials (HPCRM) program[1-2]. SAM2X5 (Fe-Cr-Mo-W-Mn-B-C-Si) material was designed to have highglass-forming ability allowing the formation of an amor-phous structure during the HVOF application process. Figure1a shows an x-ray diffraction spectrum of the as-sprayedSAM2X5 coating. The broad amorphous humps and lack ofBragg diffraction peaks are indicative of an amorphous struc-ture. In a TEM micrograph of the as-sprayed coating (Fig. 1b)shows there are no crystalline phases and the characteristic dif-fuse halo in the selected area diffraction (SAD) pattern showsthat an amorphous structure is obtained. While achieving aglass structure is paramount, it was found that the composi-tion leading to the formation of a passive protective oxide layeris also very important. Modeling multicomponent composi-tions using ThermoCalc software (ThermoCalc Software Inc.)allows developing Pourbaix diagrams showing specific favor-able ratios of key alloying elements, which preferentially mi-grate and form in the oxide layer, providing key insight incorrosion performance. Figure 1c shows a Pourbaix diagram[2]

for SAM2X5 in near-boiling seawater (90°C, or 195°F). Elec-trochemical polarization curves show the benefitsof optimizing both structure and chemistry (Fig.1d). As shown by its high repassivation potentialand low critical current density, the SAM2X5 coat-ing has resistance to corrosive attack superior to thatof wrought nickel-base Hastelloy C-22 (Haynes In-ternational) in this environment.

Arc-Spray Coatings for Boiler Applications

In high-temperature applications, such as heat-exchanger tubes in power plants, achieving bothhigh corrosion and erosion resistance is important.A solution for this environment is NanoSteel’sSHS8000 alloy (Fe-Cr-Mo-Nb-B-C-Mn-Si) de-signed with moderate glass-forming ability. Fig-ure 2a shows SHS8000 chemistry being applied tothe surface of a biomass plant using the twin-rollwire-arc coating process. A TEM micrograph (Fig.2b) shows the as-sprayed microstructure consist-ing of a glass matrix verified by the diffuse halo inthe SAD pattern and an extremely fine distributionof 2 to 5 nm sized precipitates. This mixed struc-ture containing nanoscale transition metal borocar-bide phases provides excellent hardness, abrasion,

Development of Nanostructured Coatingsfor Enhanced Corrosion PerformanceD.J. BranaganThe NanoSteel Co.Providence, RI.

FFig. 1 — a) X-ray diffraction spectrum of the as-sprayed SAM2X5 coating, b)TEM and SAD pattern of the as-sprayed SAM2X5 coating, c) Pourbaix diagramof the SAM2X5 coating in seawater (90°C), d) Electrochemical polarization curveof the SAM2X5 HVOF coating compared to wrought C-22 plate in seawater(90°C).

(a) (b)

(c) (d)

[email protected]

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and erosion resistance while maintaining high corrosion re-sistance. Upon subsequent high-temperature exposure dur-ing service, the coating’s glass matrix will devitrifycompletely. After exposure at a temperature of 1200°F(650°C) for 20 minutes, the devitrified structure is fully crys-talline and consists of phase sizes from 5 to 20 nm (F 2c).After devitrification, the hardness of the coating increases200 kg/mm2 and abrasion resistance increases by a factor of3.5. Using classical nucleation theory, it is possible tomodel[3] the transformation kinetics of the devitrification.Figure 2d shows a model time temperature transformation(TTT) diagram that illustrates the thermal exposure neces-sary to initiate devitrification, allowing predictive behavioron coating performance. iTSSe

References1. J.C. Farmer, et. al., Corrosion resistance of thermally sprayedhigh-boron iron-based amorphous-metal coatings: Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4, J. Materials Research, 22, p2297-2311, 2007.2. L. Kaufman, et. al., Transformation, Stability and Pourbaix Di-agrams of High Performance Corrosion Resistant (HPCRM) Al-loys, CALPHAD, 33, p 89-99, 2009).3. J. Zhou, et. al., Novel In-Situ Transformable Coating for Ele-vated-Temperature Applications, Journal of Thermal Spray Tech-nology, Vol 19, Issue 5, p 950, 2010.

For more information: Daniel Branagan, Ph.D., Chief TechnicalOfficer, The Nanosteel Co., 505 Lindsay Blvd., Idaho Falls, ID83402; tel: 208/552-5226; email: [email protected];www.nanosteelco.com

Development, continued

Fig. 2 — a) Application of the SHS8000 twin-roll arc-spray coating onto the heat exchange tube of a biomass boiler, b) TEM andSAD pattern of the as-sprayed SHS8000 coating, c) TEM and SAD pattern of the fully devitrified (1200°F for 20 minute heat treatment) SHS8000 coating, d) Model TTT diagram of the SHS8000 coating material illustrating time and temperature to initiate devitrification up to a one year length scale.

(a) (b) (c) (d)

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W ith the world’s growing energy demands and de-pleting oil reserves, deeper and harder to reachoil reserves are being explored and drilled. With

the technology that exists today, oil well depths beyond35,000 ft are being drilled using technology and know-howdeveloped over decades within the oil and gas industry. Thematerials needed to survive in the extreme conditions are thelimiting factor for successful operation especially in wellscontaining hydrogen sulfide (H2S), or sour gas, under acidiz-ing conditions.

Oil well stimulation by acidizing is a common practice in-volving the use of strong acids pumped through the tubularand into the oil formation. Various acids such as hydrochlo-ric (HCl), hydrofluoric (HF), acetic acid, and formic acid are

commonly used, which can cause high corrosion rates onnearly every alloy used in production. Corrosion rates can begreatly accelerated in the presence of H2S at high tempera-tures and pressures. Corrosion damage, even with the use ofhigh doses of the proper inhibitors, is expected to occur inacidizing solutions at elevated temperatures.

This article discusses a laboratory study to evaluate thecorrosion resistance of multiple alloys under acidizing con-ditions to help identify which materials are suitable in theseextreme conditions. Alloys investigated included stainlesssteel (316L), nickel-base alloy (C276), titanium alloys (Ti 6-4 and Ti 6-2-4-6), and a tantalum surface alloy (316L sur-face-alloyed with tantalum). Two tests were conducted usingtwo acidizing environments representing a mild condition(10% acetic acid) and an aggressive condition (10% HCl,10% acetic acid, 15 psia H2S); neither solution contained anycorrosion inhibitor. Tests were conducted at 450°F (230°C) torepresent the bottom-hole temperature of a deep well.

Experimental SetupDue to the highly corrosive nature of the environments, an

autoclave constructed of 316L treated with a Ta surface-alloy was used to prevent excessive corrosion and subsequentpossible failure of the pressure vessel. All internal parts ofthe autoclave were constructed of either Ta surface-alloyed316L or alumina ceramic. Photographs of the autoclave as-sembly and internals are shown in Fig. 2. As illustrated inthis article, the Ta surface-alloy was critical for equipmentintegrity in conducting the acidizing experiments.

The Ta surface alloy on all equipment, accessories, andcorrosion coupons was prepared using a proprietary processdeveloped by Tantaline. The Ta surface alloy process in-volves the production of a gaseous atmosphere of tantalumthat grows the Ta metal onto and into the substrate (Fig. 3) Tametal forms over the substrate-Ta interface, providing thechemical and corrosion resistance properties of pure Ta. Thisprocess occurs at nanoscale dimensions and at high temper-atures creating a metallurgically bonded Ta layer superior indurability to traditional coatings or electroplating.

The objective of the study was to evaluate corrosion in theworst-case condition (uninhibited) and on multiple classesof alloys. Details of the experiments conducted are presentedin Table 1.

Corrosion Test ResultsMeasured corrosion rates from the two experiments were

substantially different. Corrosion rates in the 10% acetic acidat 450°F were considered mild, with 316L exhibiting thehighest corrosion rate of 242 mpy (6.1 mm/yr). Corrosionrates in the 10% HCl / 10% acetic acid with H2S environ-ment were extremely high for all alloys except Ta surface-alloyed 316L; 316L, Ti 6-4, and Ti 6-2-4-6 couponscompletely dissolved after 8 hours of exposure and the C276samples were corroded severely.

Results of test #1: 10% acetic acid at 450°F: As expectedbased on previous investigations in organic acidizing solu-

Materials Testing for use in Strong H2S Acidizing EnvironmentsDean GambaleTantalineWaltham, Mass.Brian Chambers, Ph.D.Honeywell Corrosion SolutionsHouston, Tex.

Fig. 2 — Photographs of Ta surface-treated autoclave.

Fig. 1 — Results of corrosion and cracking evaluations in a variety ofconditions with inhibited 15% HCl.

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tions at high temperature[1-4], corrosion rates ranged from nilto moderate for the alloys evaluated. The tantalum surfacealloy and Ti 6-2-4-6 exhibited zero corrosion. The corrosionrate of 316L was 242 mpy (6.1 mm/yr), while corrosion rateson C276 and Ti 6-4 were 11.9 and 2.2 mpy (0.3 and 0.1mm/yr), respectively. Visually, all of the Ta surface alloyedequipment appeared unaffected by the exposure. Table 2shows detailed results, and coupons are shown in Fig. 5.

Results of Test #2: 10% HCl / 10% Acetic Acid / 15 psiaH2S at 450°F: Corrosion rates were extremely high for the al-loys evaluated except the Ta surface alloy. Ta surface alloycoupons showed no corrosion and were observed to have ablue tint due to plating of metallic ions from solution duringthe exposure. The 316L, Ti 6-4, and Ti 6-2-4-6 coupons allcompletely dissolved during the 8 hour exposure (Fig. 6),translating to minimum corrosion rates in the range of 16 to41 in./yr (406 to 1,049 mm/yr). C276 coupons were severelyattacked and the corrosion rate was measured at 21 in./yr(531 mm/yr). Visual inspection indicated that all of the tan-talum surface alloyed equipment and associated parts had nosigns of corrosive attack. Table 3 shows detailed test results

and post-exposure coupons areshown in Fig. 7.

The perform-ance of the

tantalum sur-face alloyed

coupons, auto-clave, and acces-

sories successfully demonstrated the good corrosionprotection provided by the Tasurface treatment process in thehighly aggressive environments.Inspection of the coupons, auto-claves, and accessories found no

indications of localized attack, blistering, or other damage tothe tantalum surface alloy or underlying substrate.

Materials Testing, continued

Table 1 — Experimental conditions for corrosion evaluation in acidizing solutions

No. of coupons Test Alloys in liquid SolutionConcentration Temperature Pressure Duration

1 316L Two per 10% acetic acid 450°F (230°C) 35 psi N2 8 hC276 alloy applied at 70°F Ti 6-4 (21°C)

Ti 6-2-4-6Ta-surface

2 alloy 10% acetic acid 15 psia H2S10% HCl at 450°F (230°C)

140 psi N2at 70°F (21°C)

Fig. 3 — Depictionof tantalum

surface alloy on 316SS.

Table 2 — Corrosion rates in 10% acetic acidat 450°F (230°C).

Weight- Average loss over Corrosion corrosion8 hour rate, mpy rate, mpy

Material exposure, mg (mm/yr) (mm/yr)

316L 30.6 193 (4.9) 242 (6.1)

45.8 291 (7.4)

C276 2.1 12.2 (0.3) 11.9 (0.3)

2.0 11.6 (0.3)

Ti 6-4 0.3 3.3 (0.1) 2.2 (0.1)

0.1 1.1 (0.0)

Ti 6-2-4-6 None 0 0

Nil(-0.1) 0

Ta surface- Nil (-0.3) 0 0alloy

Nil (-0.3) 0

Fig. 4 — Sample test rack.

Table 3 — Corrosion rates in 10% HCl /10% acetic acid / 15 psia H2S at 450°F (230°C).

Weight-loss Average over8 hour Corrosion rate, corrosion rate,

Material exposure, mg mpy (mm/yr) mpy (mm/yr)

316L Dissolved Dissolved Dissolved> 5,787 > 36,506 (> 927) > 36,517 (>928)

Dissolved Dissolved> 5,747 >36,517 (>928)

C276 3,604 20,901 (531) 20,897 (531)

3,589 20,893 (531)

Ti 6-4 Dissolved Dissolved Dissolved> 3,733 > 41,341 (>1,050) > 41,341 (>1,050)

Dissolved Dissolved> 3,718 > 41,312 (>1,049)

Ti 6-2-4-6 Dissolved Dissolved Dissolved> 1,260 >16,289 (>414) >16,289 (>414)

Dissolved Dissolved>1,259 > 16,231 (>412)

Ta-surface Nil (-1.7) 0 0alloyed 316L

Nil(-1.7) 0

www.cartech.com [email protected]

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ConclusionsIn H2S containing acidizing environments at high temperatures, traditional high-per-

formance corrosion-resistant alloys exhibit severe corrosion attack. This study demon-strates that tantalum surface alloys provide the needed corrosion resistance in deep wellenvironments. With the good corrosion protection, availability, and economics of Ta sur-face alloys, these materials offer a viable alternative to high-performance corrosion-resist-ant alloys such as nickel, titanium, zirconium, and solid tantalum. iTSSe

References:1. International Energy Outlook 2000: DOE/EIA-0484, 2000. 2. Annual Energy Outlook 2000 with projections to 2020: DOE/EIA-0383, 2000.3. Paul M. Mathias and Lloyd C. Brown, Thermodynamics of the Sulfur-Iodine Cycle forThermochemical Hydrogen Production, Presented at the 68th Annual Meeting of the So-ciety of Chemical Engineers, pp. 1-3, March 2003. 4. Ken Schultz, Thermochemical Production of Hydrogen from Solar and Nuclear Energy,Presentation to Stanford Global Climate and Energy Project, April 2003.Swagelok is a registered trademark of Swagelok Corp., Solon, Ohio.

For more information: Dean Gambale is president of Tantaline, 1050 Winter St., WalthamMA, 02451; tel: 888/268-2586; email: [email protected].

Fig. 5 — Photographs of coupons following exposure to 10% acetic acid at 450 F.Left to right: 316L, C276, Ti 6-4, Ti 6-2-4-6, Ta surface alloy.

Fig. 7 — Photographs of coupons followingexposure to 10% HCl / 10% acetic acid / 15psia H2S at 450°F (232°C). Left to right:C276, Ta surface alloy (other alloy couponswere dissolved).

Fig. 6 — Photographs of specimen test rackfollowing exposure to 10% HCl / 10% aceticacid / 15 psia H2S at 450°F (230°C).

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APPLICATION NOTE

Untreated steel surfaces can become very slippery, es-pecially in wet conditions, and are prone to corro-sion. To ensure safe walking and industrial

operating conditions, vital to personal safety and corporateproductivity, 28E ARCTEC coating provides a durable non-slip, anticorrosion coating.

Traditionally, steel structures are hot-dip galvanized orpainted to protect against corrosion. The disadvantage of

hot-dip galvanizing is that the sur-face can become slippery, andsteel cannot be painted withoutspecial primers. Painting thistype of surface, which is some-times applied with grit inclusions,also has disadvantages—the sur-faces can degrade quickly inheavy use, resulting in corrosionand an increased slip hazard.

Many large steel structures, in-cluding oil platforms, refineriesand bridges, are routinely pro-tected against corrosion by ther-mal spray aluminum (TSA), zinc,or an alloy of the two. While pro-viding unrivalled corrosion pro-tection in very aggressivecorrosive environments, pureTSA is not durable enough to pre-vent long term wear on floorplates. Ideally, steel structuresneed a durable coating that pro-tects against both slip and corro-sion—exactly what the newMetallisation 28E ARCTEC coat-ing does.

The 28E ARCTEC coating is a

thermal spray coating that can be applied with a rough tex-ture and has excellent non-slip properties, while being ex-tremely hard and resistant to wear. The new coatingprovides:

• A suitable level of grip, to avoid personal slips or industrial skidding

• Comparable corrosion protection to that of aluminumused in aggressive environments

• Easy application by a long-standing process, coveredby international standards

The coating is corrosion resistant and because of itsdurability, site owners can be confident that once applied,they can forget about rusting or slipping for many years.To prove the durability of this heavy-duty coating, Met-allisation conducted many tests in the development of 28EARCTEC wire and coating including non-slip, durability,and corrosion testing.

The 28E ARCTEC coatings were tested for non-slip anddurability using a pendulum coefficient of friction tester,in accordance with independent British Standards and UKHealth and Safety Executive (HSE) guidelines. Theseguidelines suggest that a floor coating with a pendulum testvalue (PTV) greater than 36 will have a low slip potentialin pedestrian areas. To test the coatings, the plates weresprayed to produce a surface texture that would wear well,but not too rough for pedestrian surfaces. If the surfacehas too much grip in pedestrian areas, it can cause a triphazard.

To prove the durability of the coating, coated plateswere walked on by a standard shoe on a robotic walkingmachine. The plate was rotated after each step to simulatewalking in a straight line and around corners. The PTVwas checked before walking and again after 250,000,500,000, 750,000, and 1 million steps. Both sealed andunsealed plates were tested in wet and dry conditions.

The pendulum test values obtained in accordance withBS7976-2:2002 highlighted significant results. The un-sealed plates initial wet PTV was 75, and after 1 millionsteps, it decreased to 41. Whereas the sealed plate’s initialwet PTV was 66, and after 1 million steps it had only de-creased to 58. Testing in dry conditions achieved similar

results, with a dryPTV of 80 down to 64for unsealed platesand 72 down to just 68on the sealed plates.Details of the full testresults can be seen inTable 1. The 28E ARCTEC

coating also under-went a range of accel-erated corrosiontesting, offering a

Corrosion Resistant, Non-slip Thermal SprayCoating for Harsh Industrial Environments

A surface being sprayed with 28E ARCTEC coating.

The new coating has been metalsprayed onto a fork lift truckramp.

Pendulum tester used to test the coefficient of friction of thecoating.

The 28E ARCTEC nonslip coating has been specified forthe North Raskin Platform located off the Australian coast.

www.asminternational.org/[email protected]

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comparison of the performance betweenthe new coating and 99.5% aluminum. Anindependent research laboratory con-ducted two tests: Galvanic corrosion testsfor one week and neutral salt spray corro-sion tests for 1,000 hours.

The salt spray tests were performed inaccordance with ASTM B117. The resultsconfirmed the corrosion protection offeredby 28E ARCTEC coating was comparableto 99.5% aluminum. These results givethe confidence that the new coating willprovide the same high standard of corrosion protection that alu-minum has done around the world for several decades.

An example of the 28E ARCTEC coating in use is seen on atwin-platform, offshore LNG platform installation, which hasan interconnecting bridge. Following extensive evaluation ofnon-slip coatings, 28E ARCTEC wire was applied to thebridge deck surface, because of its non-slip durability and cor-rosion protection.

The coating was also used to treat ramps used by forklifttrucks to load and unload containers. The ramps can be very

slippery in wet conditions and are often salt treated in winter.After one year there is no visible rusting of the steel substrate.Feedback from the forklift operators report a higher level ofconfidence when climbing the ramp and confirmation that theymanaged to safely and successfully load all lorries in wet conditions. iTSSe

For more information contact Stuart Milton, Metallisation Ltd., tel: 44(0) 1384 257 464; or visit www.metallisation.com.

Table 1 — Durability and Slip Test Results

Unsealed sample Sealed sample (epoxy) Cycles Pendulum test Pendulum test Pendulum test Pendulum testcompleted value, dry value, wet value, dry value, wet

Initial 80 75 72 66

250,000 66 50 70 63

500,000 65 49 71 61

750,000 64 43 69 60

1,000,000 64 41 68 58

www.asminternational.org/tss

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The Journal of Thermal SprayTechnology (JTST), the official journal ofthe ASM Thermal Spray Society,publishes contributions on all aspects –fundamental and practical – of thermalspray science, including processes,feedstock manufacture, testing, andcharacterization. As the primary vehiclefor thermal spray information transfer, itsmission is to synergize the rapidlyadvancing thermal spray industry andrelated industries by presenting researchand development efforts leading to

advancements in implementable engineering applications of thetechnology.

Articles from the March issue, as selected by JTST editorChristian Moreau, are highlighted here.

In addition to the print publication, JTST is available onlinethrough www.springerlink.com. For more information, pleasevisit www.asminternational.org/tss.

“Microstructure of Interfacial Region Between Cold-Sprayed Copper Coating and

AlN Substrate Coated with Sputtered Titanium and Copper”

Hiromi Nakano , Motohiro Yamada, MasahiroFukumoto, and Eiji Yamaguchi

In this article, copper is deposited on an AlN substrate coated bythe sputtering of titanium and copper at a low pressure of less than1.0 MPa, making this approach suitable for a wide range of engineer-ing applications. To understand the adhesion mechanism at the atomic

scale, interfacial regions arecarefully observed in thin foilsamples from the cross sec-tions of the specimens with aHREM. A unique wavyboundary exists between thesputtered titanium and thesputtered copper. It is assumedthat the shear-instability phe-nomenon occurs due to thecold-spray process and influ-ences the adhesive strength.Furthermore, the cold-sprayedcopper particles are connecteddirectly without any oxidationlayer due to the appearance of new metallic surfaces during the impactprocess. The TEM data clearly reveal the phenomena and mechanismsrelated to the impact of powder sprayed on the substrate.

“Mechanical Property Mapping of ColdSprayed Ti Splats and Coatings”

Dina Goldbaum, Richard R. Chromik, Stephen Yue,Eric Irissou, and Jean-Gabriel Legoux

Profile nanoindentation and nanoindentation mapping were used toinvestigate the mechanical properties of commercially pure cold sprayTi splats and coatings deposited at increasing deposition velocities.Three regions in the cold spray Ti splats were indentified: the impactregion, the jetting region, and the upper splat region. The mechanicalproperties measured in these regions were tied to the cold spray dep-osition process with help of optical and scanning electron micro-scopes. The jetting region was observed to contribute to ametallurgical bonding of cold spray splats to cold spray splats and wasmeasured to have low hardness compared to the splat impact site and

Schematic illustration of shear-instability phenomenon duringcold spraying.

www.universalthermal.com

www.dewal.com [email protected]

similar to the hardness in the upper splat region. No increase in theprofile coating hardness with increasing particle in-flight velocityand coating thickness was found. There is a correlation between themechanical properties and the presently known deposition temper-ature, stress, and dislocation density models.

“Manufacturing and Macroscopic Propertiesof Cold Sprayed Cu-In Coating Material for

Sputtering Target”Young-Min Jin, Jin-Hyeon Cho, Dong-Yong Park,

Ju-Ho Kim, and Kee-Ahn LeeThis study tried to manufacture a Cu-In coating layer via the cold

spray process and investigated the applicability of the layer as a sput-tering target material. In addition, changes in the microstructure andproperties of the layer due to annealing heat treatment were evalu-ated, compared, and analyzed. To examine the microstructural andproperty changes in the Cu-In coating layer and Cu coating layer(comparison material), ICP, XRD, SEM, and other tests were con-ducted to measure purity, density, hardness, porosity, and bond-strength. The results showed that coating layers with thickness of 20findings of this study the Cu-In coating layer manufactured via coldspray process and annealing heat treatment is applicable as a sput-tering target.

Results of EPMA mapping analyses following annealing treatment of the Cu-In coating layer.

“Plasma and Particle Temperature Measurements in Thermal Spray:

Approaches and Applications”Georg Mauer, Robert Vaßen, and Detlev Stöver

A critical requirement of di-agnostic methods in thermalspray is the accurate measure-ment of temperatures. Thisrefers to the hot working gasesas well as to the in-flight tem-perature of the particles. Thisarticle reviews plasma andparticle temperature measure-ments in thermal spray. Theenthalpy probe, optical emis-sion spectroscopy, and com-puter tomography areintroduced for plasma meas-urements. To determine in-

flight particle temperatures, mainly multicolor pyrometry is appliedand described in detail. The theoretical background, operation prin-ciples, and setups are given for each technique. Special interest isgiven to calibration methods, application limits, and sources of er-rors. Furthermore, examples of fields of application are given in theform of results of current research work.

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Micrograph of the cross section of a Ti splat obtainedby light optical microscopy.The flattening ratio wasmeasured from images suchas these to examine the extent of deformation of Tisplats as a function of deposition velocity.

Relevant nonthermal radiationsources influencing the temperature measurementusing two-color pyrometry.

[email protected] www.sulzermetco.com

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