News from Institutes and Research Centers Around the World

This column is a forum to inform the ther-mal spray community on current activi-ties in institutes and research centers ac-tive in the field of the thermal spray.Research efforts carried out in these orga-nizations are oftentimes the starting pointof significant developments of the tech-nology that will have an impact on theway coatings are produced and used inindustry. New materials, more effi-cient spray processes, better diagnostictools, and clearer understanding of thechemical and physical processes involvedduring spraying are examples of such de-velopments making possible the produc-tion of highly consistent performancecoatings for use in more and more de-manding applications encountered in theindustry.

This column includes articles giving anoverview of current activities or a focuson a significant breakthrough resultingfrom research efforts carried out in insti-tutes and research centers around theworld. If you want to submit an articlefor this column, please contact Jan Il-avsky, JTST associate editor, address: Ar-gonne National Laboratory, AdvancedPhoton Source, 9700 S Cass Ave., Ar-gonne, IL, 60439; e-mail: JTST.Ilavsky@aps.anl.gov.

Laboratory of Diagnostics andImaging of Industrial Processes,National Engineering School ofSaint-Etienne

The Laboratory of Diagnostics and Imag-ing of Industrial Processes (DIPI) at Na-tional Engineering School of Saint-Etienne was established in 2001. In 2003it was labeled with prestigious title HostTeam (EA 3719) by the French ResearchMinistry.

The staff currently consists of seven fulltime faculty, eight students of differentlevels, two engineers, and three techni-cians. The laboratory has about 700 m2 ofexperimental facilities and about 150 m2

of research and administrative offices.The main experimental equipment con-sists of different kinds of lasers for 3Dcladding and direct manufacturingincluding TRUMPF DMD 505 andPHENIX PM-100 machines, industrialtype spraying booth with cold spray andwire spray systems.

The major research objective of the DIPIis fabrication of graded/nanostructuredcoatings/tools using laser-assisted depo-sition and thermal spraying technologies.The main research directions are: (a) pro-cess engineering (high-temperature in-dustrial processes employing concen-trated energy sources—laser, plasma,flame; manufacture and treatment ofhigh-temperature materials includingprotective coatings); (b) modeling of in-dustrial process (high-temperature heatand mass transfer in thermal spraying, la-ser-assisted processes, etc.); (c) Diagnos-tics by pyrometry, spectroscopy, andCCD camera imaging (laboratory usesa unique set of optical diagnostic toolsincluding 12 wavelengths and 2D py-rometers, several advanced CCD-camera-based image processing systems,etc.). On-site spray setup is available toperform development of innovative coat-ings (including the nanostructured coat-ings).

National Engineering School of Saint-Etienne (ENISE) has participated ina number of nationally and interna-tionally funded programs and projects,namely Growth, Craft, Copernicus,Brite/Euram, and INTAS. For exam-ple, ENISE was a coordinator of recentlycompleted (2001-2004) Growth proj-ect TRIBO “Nanostructured Coatingfor Engineering Tribological Applica-tions.”

Optical DiagnosticsA new diagnostic system was developedfor real-time monitoring of in-flight par-

ticle diameters, velocities, and tempera-tures. The system is based on the nonin-tensified CCD image sensor with highsensitivity in near-infrared spectral re-gion. An original software package de-veloped in-house and used for calibra-tion, treatment of powder jet gray image,and statistical analysis of particleparameters is the essential part of the sys-tem.

This diagnostic system was tested un-der actual industrial conditions ofplasma spraying and laser claddingprocesses for three visualization modes:(a) jet visualization (real image ofjet structure and its evolution apply-ing different spatial and temporalscales); (b) particle/substrate interac-tion (particle sticking, particle splash-ing), visualization of near substratezone for powder rebound monitoring;(c) Dynamics of coating growth includ-ing quantitative estimations of its thick-ness in real time. Experiments wereperformed for a wide range of indus-trial equipment and for various geo-metry of spraying parts (cylinder, plate,etc.). Typically, the systems studied areTBC (ZrO2 and Al2O3) and wear-resistant coatings (WC-Co, Mo, CuSn,etc.).

Statistical processing of recorded data onparticle size, velocity, and temperature(Fig. 1) was carried out to develop under-standing of the influence of processvariables (arc current, plasma forminggases flow rates, oxygen and fuel flowrates, powder flow rate, carrier gas flowrate, spraying distance, laser power, clad-

Fig. 1 Histograms of powder diameter, speed, and temperature for nominal spraying conditions.Spraying of Cr2O3 powders (grain size–53+5 µm) by Plasma Technik system.

JTTEE5 15:464-468DOI: 10.1361/105996306X1576201059-9630/$19.00 © ASM International

464—Volume 15(4) December 2006 Journal of Thermal Spray Technology

ding velocity, etc.) on powder param-eters.

The particle flux can be visualized in realtime and therefore can be used for moni-toring of its position, direction, density,and homogeneity. When observing thenear-substrate region, the camera easilydistinguishes the particles that adheredand that rebounded, allowing analysisof the powder loss and improvement ofthe deposition efficiency. This diagnosticsystem demonstrated high performance:10 µm particle size detection limit, de-tectable temperature range 1200 to3500 °C, and particle velocity rangefrom 1 m/s up to 900 m/s. The resultscompared favorably with the results ob-tained with the DPV 2000 diagnostic sys-tem.

This CCD-camera-based diagnostic sys-tem can be also applied in industry forboth spraying and cladding process opti-mization (correct spraying distancechoice, powder injection optimiza-tion, maximum efficiency of powderusage, coating growth control, etc.) andfor real-time monitoring of process stabil-ity.

Numerical SimulationA project using simulation of plasmaspraying is underway at DIPI. The simu-lation takes into account nonuniform tem-perature distributions inside particles inthe plasma flow and their melting andevaporation. The spray process is ana-lyzed based on numerical integrationof model differential equations. The de-veloped model is especially useful in caseof nonuniformly heated and partiallymelted and evaporated particles. Suchsituations may arise when extending therange of materials or plasma flow param-eters.

The dynamic equation for the parti-cle is

dV� p

dt=

3

4� CD �

�g�V� g − V� p� � �V� g − V� p�

�pdp+ g�

(Eq 1)

where V� p is the particle velocity, g� is thegravity acceleration, V� g is the gas veloc-ity, �p is the particle mass density, dp isthe particle diameter, CD is the drag coef-ficient. The convective thermal flux fromthe plasma to the particle is:

Q = Nu � �g �Tg − Tps

�dp(Eq 2)

where Nu is the Nusselt number; �g is thegas thermal conductivity; Tps is theparticle surface temperature; Tg (X,Y) isthe ambient gas temperature. The func-tion Tg (X,Y) is considered to be knownlike V� g(X,Y) in Eq 1. The drag coefficientand the Nusselt number are known func-tions of the Reynolds and Prandtl num-bers.

The temperature distribution andphase transformations in the particle aredescribed by:

�p �h�T1�

�t=

1

r2

�

�r �r2�1�T1��T1

�r �, r ∈ �0;��

(Eq 3)

�p �h�T2�

�t=

1

r2

�

�r �r2�2�T2��T2

�r �, r ∈ ��;��

(Eq 4)

T1��,t� = T2��,t� = Tm (Eq 5)

�Lm

d�

dt= �1�Tm�

�T1

�r�r = �+0

− �2�Tm��T2

�r�r = �−0

(Eq 6)

�Lv

d�

dt= �2�T2�

�T2

�r+ Q�T2�, r = �

(Eq 7)

where t is the time; r is the radius; T1(r,t),T2(r,t) are the temperature distributions

in the solid and liquid phases, respec-tively; Lm is the latent heat of melting;Lv is the latent heat of evaporation; Ts

is the particle surface temperature; Tm

is the melting point; h(T) is the spe-cific enthalpy of the particle material;�1(T), �2(T) are the known thermal con-ductivities for the solid and liquid phase,respectively. The problem is character-ized by the two mobile bounds: evapora-tion interface �(t) and solid/liquid inter-face �(t). These bounds divide thecalculation domain into two parts [0;�]and [�, �], respectively. Expressions 3and 4 are the heat conduction equations insolid and liquid phases written in spheri-cal geometry (the particle is assumed tohave a spherical shape). The tempera-ture at the solid/liquid interface is al-ways constant and equal to Tm (Eq 5).Equation 6 represents the Stefan bound-ary condition at the solid/liquid interface.Equation 7 is the boundary condition atthe particle surface, which involves en-ergy flux Q through the surface of the par-ticle (Eq 2).

As an example of the obtained results,Fig. 2 shows calculated particle tempera-ture in its center and at the surface.

A considerable expertise in combiningcharacterization and modeling allowsDIPI to address development challengesin the field of novel materials for compos-ite, graded and nanostructured coatingsdeposition.

Contact: Dr Philippe Bertrand,ENISE DIPI lab., 74 Rue des Aciéiries42000 Saint Etienne, France; Tel. +33 477 91 01 60; Fax +33 4 77 74 34 97; E-mail: bertrand@enise.fr.

Fig. 2 Temperature evolution of Al2O3 particles with several diameter values in Ar plasma jetversus the distance from the powder feeder. Plateaus in the center (left) and salient points at thesurface (right) correspond to melting.

Journal of Thermal Spray Technology Volume 15(4) December 2006—465

Industrial News

Thermally Sprayed Golf ClubsAchieve Improved Backspin

SpinPro, a technologically advanced hardand wear-resistant coating applied to theclubface of short irons and wedges to im-prove backspin up to 2.5 times, delivershigh spin rate through a unique texture,definitive surface roughness, and anoptimized microstructure and modulus ofelasticity. LinSpray technology wasdeveloped by Linde AG, Linde Gas Divi-sion, then put into practice at Linde’sApplication Technology Centre. Thefaces of different clubs were coatedand the process optimized to obtain thebest possible result by using a spe-cial spraying material and the required in-dustrial gases as carriers of thermal andkinetic energy. Sulzer Metco is the exclu-sive licensee of SpinPro golf club coat-ings.

Contact: Peter Heinrich, Linde AG,Linde Gas Division, Carl-von-Lind-Strasse 256, 85716 Unterschleissheim,

Germany; Tel: 0049 89 31001 564; E-mail: Peter.Heinrich@Linde-Gas.com;Web: www.spinpro.de.

News from NASA

Blanch-Resistant and ThermalBarrier NiAl Coating Systemsfor Advanced Copper AlloysU.S. Patent 6,838,191. Sai V. Raj,John Glenn Research CenterCopper alloys containing chromium andniobium are being considered for use ascombustor and nozzle liners in reusablelaunch vehicle applications. Unprotectedcopper alloys degrade during use inrocket engines in a process called blanch-ing. Repeated exposure to the hydrogen/oxygen combustion mixture causes oxi-dation and reduction of the alloy, leadingto failure or reduced useful life of thecomponent.

This method forms an environmentallyresistant thermal barrier coating on a cop-per alloy. In particular, the present inven-tion addresses issues related to the designand deposition of suitable coatings andbond coating technology for protecting anadvanced copper alloy known as GRCop-84. The steps include cleansing a surfaceof a copper alloy, depositing a bond coaton the cleansed surface of the copper al-loy, depositing a nickel aluminide (NiAl)top coat on the bond coat, and consolidat-ing the bond coat and the NiAl top coat toform the thermal barrier coating.

Excerpted from NASA Tech Briefs, July2006.

Lower-Conductivity CeramicMaterials for Thermal BarrierCoatingsDoped pyrochlore oxides of a type de-scribed below are under consideration asalternative materials for high-temp-erature thermal barrier coatings (TBCs).In comparison with partially yttria-stabilized zirconia (YSZ), which is thestate-of-the-art TBC material now incommercial use, these doped pyrochloreoxides exhibit lower thermal conductivi-ties, which could be exploited to obtainthe following advantages:

• For a given difference in temperaturebetween an outer coating surface andthe coating/substrate interface, thecoating could be thinner. Reductions incoating thicknesses could translate toreductions in weight of hot-sectioncomponents of turbine engines (e.g.,combustor liners, blades, and vanes) towhich TBCs are typically applied.

• For a given coating thickness, the dif-ference in temperature between theouter coating surface and the coating/substrate interface could be greater.For turbine engines, this could trans-late to higher operating temperatures,with consequent increases in effi-ciency and reductions in pollutingemissions.

Thermal barrier coatings are needed be-cause the temperatures in some turbineengine hot sections exceed the maximumtemperatures that the substrate materials(superalloys, Si-base ceramics, and oth-ers) can withstand. Yttria-stabilized zir-conia TBCs are applied to engine compo-nents as thin layers by plasma spraying orelectron beam physical vapor deposition.During operation at higher temperatures,YSZ layers undergo sintering, which in-creases their thermal conductivities andthereby renders them less effective asTBCs. Moreover, the sintered YSZ TBCsare less tolerant of stress and strain and,hence, are less durable.

The materials that are sought as alterna-tives to YSZ are required to have and re-tain lower thermal conductivities and tobe better able to withstand temperaturesthat degrade TBCs made of YSZ. The un-doped versions of the type now underconsideration as alternatives to YSZ areof general composition Ma2Mb2O7,where Ma denotes a 3+ cation (for ex-ample, La to LU), and Mb a 4+ cation (forexample, Zr, Hf, Ti). Doping has been in-vestigated as a means of reducing thermalconductivities even further below thoseof YSZ coatings. In the doping approachinvestigated thus far, another cation issubstituted for part of Ma, yielding a gen-eral composition of Ma2–xMxMb2O7,

The effect of a SpinPro coated club

466—Volume 15(4) December 2006 Journal of Thermal Spray Technology

where x lies between 0 and 0.5 and M de-notes a rare earth or other suitable ele-ment.

In experiments, powders of various com-positions were synthesized by a modifiedsol-gel method and calcined at appropri-ate temperatures to convert them intocompounds of pyrochlore structure asconfirmed by x-ray diffraction. Thesepowders were hot pressed into densedisks of 1 in. (2.54 cm) diameter. Thethermal conductivities of the disks weremeasured at various temperatures up to1550 °C by use of a steady-state laser heatflux technique. Figure 1 presents resultsof such measurements performed on sev-eral materials of general compositionLa2–x(Gd and/or Yb)xZr2O7, where x = 0or 0.3. The thermal conductivities of alldoped samples (x = 0.3) were less thanthose of the undoped (x = 0) sample[La2Zr2O7]. The lowest conductivity—ranging from 40 to 50% below that of un-doped sample—was exhibited by thesample codoped with both Gd and Yb.

This work was done by Narottam P.Bansal of the John H. Glenn ResearchCenter and Dongming Zhu of the U.S.Army Research Laboratory. For furtherinformation, access the Technical Sup-port Package (TSP) free on line at www.

techbriefs.com/tsp under the Materialscategory. Inquiries concerning rights forthe commercial use of this inventionshould be addressed to: NASA Glenn Re-search Center, Innovative Partnerships

Office, Attn. Steve Fedor, Mail Stop 4-8,21000 Brookpark Rd., Cleveland, OH44135. Refer to LEW-17469-1. Ex-cerpted from NASA Tech Briefs, Sept2006.

News from ITSC and TSS

United Nations of ThermalSpray

During the ITSC 2006 in Seattle, morethan 20 top-level representatives from tenglobal thermal spray societies based innine countries on four continents gath-ered for a general introductory meeting togive brief overviews of their respectiveorganizations, get to know each other,and exchange ideas for cooperation.Many of the global industry societies en-gage in similar activities and also offersimilar products and services to theirmembership and a commonly shared ob-jective is to provide value to their mem-bers and to help the thermal spray indus-try grow beyond its current applicationsand customer base. Therefore, it wasagreed upon that a certain level of coop-eration between the global societiesmight be desirable. In fact, the concept ofhaving an internationally representativegroup engaged in cross-border discus-sions related to the thermal spray industryand the opportunities that are presenting

themselves triggered some furtherthought and discussions among some ofthe attendees. In order to facilitate com-munication, networking, cooperation,and coordination among the global soci-eties and to foster industry growth it wassuggested to create a general institution ofglobal societies under the name “UnitedNations of Thermal Spray” (UNTS).There was a general consensus thata closer global cooperation would bene-fit individual societies and that a moreformal approach could develop from thebasic startup mode. The participantsagreed to meet again during the ITSC2007 in Beijing where further optionsand suggestions regarding this institu-tion should be discussed. Societies whoshare the aforementioned objectives andviews and who wish to engage in interna-tional cross-border communication andcooperation should contact Peter Han-neforth, ASM/TSS President Elect andProgramming Chair, SpaCom, 223 WallStreet #160, Huntington, NY 11732,peterhanneforth@spacom.com.

TSS Board Election Results

In accordance with the Rules of Gover-nance, the ASM Thermal Spray Societycompleted its election of officers andBoard members. The TSS Board mem-bers represent the industry (suppliers,service organizations, and users), univer-sities (academia), research and develop-ment organizations, government agen-cies, and the international thermal spraycommunity. The Board is responsible tothe members of the Thermal Spray Soci-ety and the ASM International Board ofTrustees.

Peter Hanneforth,President, SpaComLLC, Huntington,NY, becomes Presi-dent for 2006-2008.H e p r e v i o u s l yserved on the Boardas a member andmost recent ly asV i c e P r e s i d e n t .

Fig. 1 Measured thermal conductivities of hot-pressed disks of several related pyrochlore oxidecompositions illustrating the benefit afforded by doping

Peter Hanneforth

Journal of Thermal Spray Technology Volume 15(4) December 2006—467

Dr. Richard Knight,FASM, Auxiliary Pro-fessor and CPPM Di-rector, Drexel Uni-versity, Philadelphia,Pennsylvania, re-mainson theBoardfortwo years as Immedi-ate Past President.

The following mem-bers were elected in2006.

Mitchell R. Dorf-man, Director of Ce-ramics, Materials De-velopment, SulzerMetco (US) Inc.,Westbury, NY, hasbeen elected VicePresident for twoyears and will auto-matically progress toPresident. Dorfmanhas served on the

Board since 2004. He has more than 27years of thermal spray material develop-ment experience and has been an activemember in the thermal spray communityfor more than 18 years, serving as chairmanof the ASM/TSS Information and Develop-ment Committee; participating in thermalspray related conferences as program orga-nizer, session chair, and workshop instruc-tor; and serving as reviewer of technical pa-pers for JTST. He has authored more than50 technical papers and holds 14 patents,and he received the Distinguished AlumniAward in 2003 from the Center of ThermalSpray Research at SUNY of Stony Brook.AsASM-TSSSocietyVicePresident,Dorf-man intends to promote thermal spray edu-cation, information dissemination, andmembership through strong committees tocreate products and services for the mem-bership, to improve the ASM-TSS websiteto strengthen global reach for new member-ship, and to continue to develop strong tech-nical conference programs.

Raymond J. Sina-tra, Senior Engineer,Rolls-Royce Corp.,Indianapolis, IN. Si-natra has worked inthe field of thermalspray coatings for 36years and has been anactive participant inthe ASM TSS duringthe past ten years,serving on the TSS

Board since 2003 and serving on the TSSStrategic Recognition Committee and Ac-

cepted Practices Committee on Metallogra-phy, as well as on the ASM Surface Engi-neering Congress Organizing Committee.Sinatra also has been reelected to a secondterm on the TSS Board from 2006-2009. Hebelieves that the ASM Thermal Spray So-ciety needs to be a strong resource for tech-nical information required to support theever-growing global business of coatings;that the information TSS develops and sup-plies to its members must be accurate,timely, and represent the latest advances incoating technology; and that training in allaspects of thermal spray will continue to bea strong member-driven need that TSSmust address by developing the appropriateresources.

The following are newly elected Boardmembers for 2006-2009:

Richard Bajan ,Thermal Spray Coat-ing Engineer, Tur-bine Component Ser-v i c e s - G o o d r i c h ,Hodges, SC. Bajanhas been an activemember of the ther-mal spray commu-nity for the past 15years, serving on theASM Thermal Spray

Division Committee on Testing and Char-acterization and the TSS Safety, Training,and Recommended Practices Committees,and he has participated in thermal spray re-lated conferences both as a speaker and ses-sion chair. He also has authored articles forSpraytime. Bajan is looking forward toserving on the Board, particularly to en-courage greater member participation onTSS committees, to work through ASMchapters to bring greater awareness aboutthermal spray technology, and to help orga-nize technical programming at pertinentthermal spray related events.

Dr. Basil Marple,Senior Research Of-ficer, National Re-search Council ofCanada, Boucher-v i l l e , Quebec ,Canada. Marple hasbeen active in thefield of materials re-search for 30 years,serving on a numberof committees and

serving in leadership roles in various pro-fessional societies. He has been active in theASM TSS as member of the JTST Interna-tional Board of Review, Panel of Judges,and Best Paper Award Committee; JTST

guest editor, member of the TSS Nominat-ing Committee, and he has participated inITSC as a program organizer and proceed-ings coeditor. He also has served on theBoard of Directors of the Canadian Ce-ramic Society. Marple views the ASMThermal Spray Society as one of the primemotors to bring together stakeholders in thethermal spray community of researchers,powder and equipment developers and dis-tributors, coating specialists, and end-users.He is interested in continuing to advancethe field of thermal spray technologythrough sponsored events showcasing thelatest breakthroughs and developments andby providing networking opportunitieswhere the various players exchange ideas,discuss challenges, and work collectively tosolve problems.

Dr. Chr i s t ianMoreau , GroupLeader Surface Tech-nologies, NationalResearch Council ofCanada, Boucherville,Quebec, Canada.Moreau has been in-volved in ASM-TSSactivities since 1999,contributing to JTSTas an author and guest

editor; serving as JTST Editor-in-Chiefsince 2004; participating in conference ac-tivities as a member of the ITSC Organiz-ing Committee and ASM TSS Program-ming Committee, and symposium andsession chair; and serving as member ofJTST Editorial Committee, Informationand Development Committee, and TSSBoard Nominating Committee. He also hasbeen active in a number of other technicalsocieties. Moreau believes thermal spraywill continue to evolve due to the close re-lationships among research scientists, ap-plication engineers, and practitioners at thenational and international levels. He intendsto promote these interactions, as well as theexchange of information and ideas amongall members of the TS community to stimu-late the growth of the industry.

In addition, PresidentHanneforth has ap-pointed Charles M.Kay, ASB Industries,Barberton, OH, asSecretary/Treasurerfor 2006-2007. Kayhas served on theBoard since 2005 andwill remain on theBoard until 2008.

Richard Knight

Mitchell R. Dorfman

Raymond J. Sinatra

Richard Bajan

Basil Marple

Christian Moreau

Charles M. Kay

468—Volume 15(4) December 2006 Journal of Thermal Spray Technology