47WELDING JOURNAL

The origins of soldering can be tracedback several thousands of years to artisansin the Mediterranean region who used itto fabricate items ranging from householdutensils to jewelry. The obvious advantagewas the low melting temperature of thefiller metals that allowed soldering to beused with the modest heat sources thatwere available at the time. Because arti-sans practiced soldering as a craft, theyconsidered materials and processes to beproprietary information. Even today,some soldering methods are not readily di-vulged between craftsmen in the jewelry-making community.

Soldering remained largely an artisan’scraft up to the Industrial Revolution in thenineteenth century. As populations grewand inhabited cities, it was necessary to de-velop an infrastructure that could delivercentralized services such as water, wasteremoval, and gas for lighting purposes.Services were brought to dwellings by iron,copper, and steel conduits that werejoined together with solder filler metals —Fig. 1. The availability of portable energysources, including combustible gases fol-lowed by electricity, allowed pipe systemsto be assembled on-site, which signifi-cantly reduced the project cost. All of thework was performed by craftsmen whoformed the ranks of plumbers and otherpipefitters.

The twentieth century brought aboutthe increased use of electricity, and with it,the development of radio and other elec-tronic components. Soldering was a veryeffective means to connect copper wires aswell as to assemble rheostats, transform-ers, and other devices. At that time, all ofthe soldering was performed by hand.There became an increased awareness ofhand soldering as an industrial process, al-

beit primarily still as a craft and certainlynot yet as a technology.

The electronics revolution of the lastfifty years saw a transition from hand-soldered electronic products to those madeby large-volume, mass production tech-niques. Automated and semiautomatedmanufacturing processes are being used toprecisely control the filler metal, flux, andapplication of heat in order to assembletens of thousands of very small solder jointsin a process time of 45–60 s and with defectlevels of tens of parts per million or less.

Today, soldering is considered a tech-nology driven by the electronics industry.It is critical that engineers understand ma-terials’ compatibility, process control, andlong-term solder joint reliability. Yet, inspite of the many advances that have beenmade toward optimizing large-volume

manufacturing processes, applications re-main that are performed by hand solder-ing because of technical and/or economicadvantages. In the electronics industry,there are accredited certification pro-grams administered by professional or-ganizations (e.g., IPC-Association Con-necting Electronics Industries) that trainindividuals in the soldering of circuitboards and related electronic intercon-nections. Those same organizations pro-vide acceptance specifications that assessthe quality of such solder joints.

However, in the case of structural handsoldering, there is a noticeable lack of ac-credited certification programs and speci-fications, in spite of the long history thathand soldering has had in the trades andartists’ communities. The American Weld-ing Society provides a quality-related doc-ument pertaining to structural solderingtitled B2.3: 2008, Specification for Solder-ing Procedure and Performance Qualifica-tion. Otherwise, most certification pro-grams are in-house and typically addressthe fabrication of solder joints that are rel-evant to that company’s products andservices. Often, operators are providedwith only a sufficient amount of informa-tion to maintain the assembly linethroughput.

The C3B Soldering Subcommittee ofthe AWS C3 Brazing and Soldering Com-mittee has long-recognized that there is agap in the availability of accredited speci-fications and certification programs. But,more so, there is a gap in the fundamentalknowledge base that is crucial to supporthand soldering as an engineering technol-ogy. Therefore, the C3 Committee hastaken action toward eliminating thatknowledge gap. The first step was to begindeveloping American National Standards

BRAZING & SOLDERING TODAY

Hand Soldering BasicsA new guideline under development highlights hand

soldering as an engineering technology

BY PAUL T. VIANCO

PAUL T. VIANCO (ptvianc@sandia.gov) is with Sandia National Laboratories, Albuquerque, N.Mex. He is a past chair of the AWS C3Committee on Brazing and Soldering.

Fig. 1 — A long-standing structural appli-cation of hand soldering is in the plumbingtrades. (Photo courtesy of the Copper De-velopment Association, Inc., New York,N.Y.)

Vianco B&S Feature Sept 2011_Layout 1 8/9/11 8:26 AM Page 47

BRAZING & SOLDERING TODAY

SEPTEMBER 201148

Institute-approved specifications for sol-dering, beginning with the C3.11 docu-ment, Torch Soldering, which is currently inthe final stages of review by the AWSTechnical Activities Committee. The sec-ond step was development of a guidelinededicated to providing a basic under-standing of the materials and process stepsthat underlie hand soldering. That docu-ment is titled Guideline for Hand SolderingPractices. The first draft has been com-pleted and the document is currently ininitial layout at AWS. The guideline is ide-ally suited for operators as well as manu-facturing and process engineers. It is alsoan excellent resource for engineering andproduct managers.

Here is a summary description of thechapter topics. The first four chapters ad-dress the fundamental aspects of solder-ing, including base materials, filler metals,as well as fluxes and controlled environ-ments. These chapters are not intended tobe in-depth treatises on these topics; forthat level of detail, the reader is referredto the corresponding chapters in the AWSSoldering Handbook, which was publishedin 2000. Instead, these chapters are in-tended to provide sufficient informationto support the operator and manufactur-ing engineer in the development of newhand soldering processes as well as thetroubleshooting of problematic processes.

The fifth chapter examines process de-velopment and is the heart of the text. Thechapter is divided into 11 sections. The

sections that address specific hand solder-ing practices are listed below:

• Soldering with an iron,

• Soldering with a torch (flame),

• Soldering with hot air or a hot inert gas,

• Resistance soldering,

• Induction soldering, and

• Other hand soldering techniques.

Each section begins with a brief intro-duction. Next, the specific equipment isdescribed that is used in the process. Then,the steps are listed for the general solder-ing process, including the placement offlux and the heat source on the base ma-terials. In several sections, the solderingprocedure details are further brokendown into applications that are best suitedfor preforms, solder paste, or wire as themethod to supply filler metal to the joint.In other chapters, the distinction is alsomade between soldering procedures forlap joints vs. those for butt joints.

There are sections within this chapterthat address preassembly cleaning and fix-tures, as well as postassembly cleaning.There is also a section that examines re-work and repair of solder joints when theyare performed by hand soldering.

The sixth chapter provides environ-

mental safety and health information. Ithas two sections: The first looks at the haz-ards of hand soldering while the secondsection examines regulations and guide-lines. The objective of the latter sectionwas not to provide an up-to-date list of rel-evant federal, state, and local regulations.Such a goal would be untenable, giventheir quantity as well as the rapid pacewith which such regulations are changingat the present time. Rather, this chapterprovides basic safety and environmentalinformation for the operator and manu-facturing engineer to consider when exe-cuting a hand soldering process. The userof the guideline is encouraged to obtainfurther details for their particular need orapplication.

An important feature of this guidelineis the illustrations. The author is all too fa-miliar with the fact that solder joints arenot well presented using standard lightphotography. Shiny surfaces and extrane-ous shadows cause misleading surface ar-tifacts. Therefore, photographs are usedsparingly. Rather, greater use is made ofschematic illustrations to demonstrate sol-der flow and fillet geometries — Fig. 2.

The C3 Committee members are en-thusiastic about this new guideline. Thedocument creates a technical frameworkfrom which to develop, and then properlyexecute, a hand soldering process that isappropriate for the choice of base materi-als, filler metal, and heat source for an application.♦

Acknowledgment

Sandia National Laboratories is a mul-tiprogram laboratory managed and oper-ated by Sandia Corp., a wholly owned sub-sidiary of Lockheed Martin Corp., for theU.S. Department of Energy’s NationalNuclear Security Administration underContract DE-AC04-94AL85000.

Fig. 2 — Examples of the types of schematic diagrams used in this guideline to illustrateprocess steps and successful solder joint geometries.

Iron Man Comic Book,Welding Career DVDs

Available for FreeCopies of four unique resource ma-

terials, including the Careers In Weldingmagazine, Iron Man comic book, andHot Bikes, Fast Cars, Cool Careers andCareers In Welding DVDs, may be re-quested for free.

Just visit www.CareersInWelding.com, click on the welding publicationslink, and fill out the form specifying thequantity you need of each item.

Vianco B&S Feature Sept 2011_Layout 1 8/9/11 8:27 AM Page 48

49WELDING JOURNAL

BRAZING & SOLDERING TODAYTECHNOLOGY NEWS

Microstructure andElectrochemical Properties ofthe Stainless Steel BondingZone Joined with a Fe-Based Amorphous Foil

The effect of temperature and holdingtime on the microstructure and corrosionresistance of the junction zone of AISI316L stainless steel (SS) bonded to itselfwith Fe75Cr8P10B7 filler alloy was investi-gated at the Instituto de InvestigacionesMetalurgicas, Mexico (Ref. 1). The braz-ing alloy was prepared in the form ofamorphous ribbons, and its melting tem-perature was determined by differentialthermal analysis to be 1571 K. The joiningprocess was carried out in a chamber withcontrolled argon atmosphere by self-dif-fusion bonding at solid state at 1173 K for20–40 min and by diffusion brazing at 1273K for different holding times <40 min.

When joined by self diffusion, thechange to the noncrystalline structure ofthe amorphous alloy and the formation ofdifferent phases made the dissimilar na-

ture of the alloys more significant and pro-moted selective dissolution coupled withcrevice corrosion.

The joints produced at 1273 K for 40min exhibited no porosity in the reactionzones and presented the best quality.Scanning electron microscopy (SEM)characterization of the bonding zone re-vealed an improvement in the quality ofthe joints brazed at 1173 K for 20 min andlonger. These samples had continuousbase metal-filler alloy interfaces with min-imum porosity. At 1273 K, the bonding in-terfaces diffused and for the samples heldfor 40 min completely vanished and poros-ity disappeared. Even the presence of par-ticle precipitates in the bonding zoneshowed acceptable resistance to localizedcorrosion in nonaggressive electrolytes.

The SEM study revealed that irregu-larly precipitated particles and otherphases of about 10 microns in size formedin the interlayer during the joiningprocess. The presence of σ phase in sam-ples bonded at 1273 K promoted prefer-ential dissolution in the bonding zone inNaCl solution.

Imidazole Containing SurfaceTreating Agent to Improve theSolderability of Printed CircuitBoards with Lead-Free Solders

A surface-treating agent, which signif-icantly improves wetting and spreading oflead-free solders on copper substrate, wasinvented and tested by Shikoku ChemicalsCorp., Kagawa, Japan (Ref. 2). The activecomponent in the surface-treating agent isan imidazole compound such as 2-Benzyl-5-methyl-4-(4-octylphenyl)imidazole or 2-(40Butylbenzyl)-5-hexyl-4-phenylimizoleadded in the amount of 0.15–0.20 wt-%.

Also, the surface treating agent con-tains acetic acid 20–30 wt-%, levulinic acid10 wt-%, copper acetate 0.05–0.10 wt-%,zinc acetate 0.9–2 wt-%, potassium chlo-ride, or bromide, or iodide 0.05–0.07 wt-%, copper iodide 0.02 wt-%, and option-ally formic acid 5 wt-%. All componentsare dissolved in deionized water, and thepH is adjusted to the value of 2.7 with am-monia water.

A printed circuit (or wiring) board isdipped in the surface-treating agent for

For info go to www.aws.org/ad-index

Technology News September Layout_Layout 1 8/9/11 9:59 AM Page 49

120–180 s at 40°C, washed with water, anddried. The solderability test was carriedout using the standard tin-lead eutecticsolder and a lead-free solder Sn-3Ag-0.5Cu at 245°C in air. The solder flow-uprate reached 100% for the Sn-Pb solderand 94–96% for the lead-free solder afterthe surface treatment, while comparativetest showed only 72–77% and 40–44%, re-spectively. Spreading of both solders oncopper was improved by 45–50% for theeutectic Sn-Pb solder and by 15% for thelead-free solder.

Transient Liquid Phase Soldering of Copper Using Tin Interlayer

An original transient liquid phase(TLP) soldering process of copper under2%H/98%N forming gas and slight com-pression was studied in The University ofNottingham, UK (Ref. 3). A thin inter-layer of pure tin foil 25 microns thick wassandwiched between two pieces of 100 mi-crons (0.004 in.) thick copper foil as a basemetal, compressed by 122 g loose weight

and reflowed at 260°, 300°, and 340°C for5–480 min.

Two adjacent layers of Cu6Sn5 andCu3Sn intermetallics were observed at theinterface between Sn and Cu, whereby mi-crostructures showed Cu6Sn5 scallops andCu3Sn columnar crystal morphologies.There is the pronounced difference inthicknesses of the Cu6Sn5 and Cu3Sn lay-ers formed at the two original boundaryplanes in the Cu/Sn/Cu samples.

After the residual Sn had been con-sumed completely, the Cu3Sn layer grewat the expense of the previously formedCu6Sn5 layer until it disappeared. Thefinal TLP joint consisted of two layers ~2microns thick of Cu3Sn columnar crystalsthat were perpendicular to the originalCu/Sn boundary planes. Diffusion kineticsof the interfacial reactions in theCu/Sn/Cu system is characterized by acti-vation energy 84.59 ± 25.84 kJ/mol, andthe Cu6Sn5 and Cu3Sn growth is derivedfrom a range of Sn interlayer thicknesses.A type of grain boundary/molten channel-controlled growth of Cu6Sn5 has a timedependence similar to that for the volume

diffusion-controlled growth.These results provide new insight into

the mechanism and kinetics of the interfa-cial reaction between liquid tin and solidcopper, and other similar metallic liq-uid/solid systems.

A Wedge Fracture ToughnessTest for Brazed Joints

It is well known that standard speci-mens used for testing fracture toughnessof solid materials are not well suited fortesting brazed joints because they are dif-ficult to reproducibly precrack by fatigue.Scientists at the University of California,Santa Barbara, Calif., designed and testeda new original, double cantilever beam(DCB) specimen to measure fracturetoughness of brazed joints, which allowspromotion of crack stability using a simpleprecracking fixture (Ref. 4).

The specimen (Fig. 1) is loaded with a30-deg silicon nitride wedge and simplysupported. For the brazed joint measure-ments, the specimen dimensions are asfollows: a = 2.54 mm, b = 6.35 mm, d =3.81 mm, h = 4.76 mm, L = 9.17 mm, andt = 1.27 mm. The design of the DCB spec-imen is guided by analytical solutions forenergy release rate and compliance.Measurements of fracture toughness useboth fractographic and compliance meth-ods to ascertain crack length.

The approach confirming test was car-ried out with 304 stainless brazed jointsand Nicrobraz® 31 filler metal. The jointshad fracture toughness ~ 1 kJ/m2 that issignificantly greater than that for inter-metallic constituents. Approximately halfof the toughening was attributed to plas-tic stretch of the ductile phase within theeutectic. The rest was attributed to dissi-pation within a plastic zone of the joint,where the crack was attracted to the interface.

BRAZING & SOLDERING TODAY

SEPTEMBER 201150

TECHNOLOGY NEWS

Fig. 1 — The simply supported, double can-tilever beam specimen is loaded with a 30-deg silicon nitride wedge.

For info go to www.aws.org/ad-index

b

td

Test Load

Load PointDisplacementGage Point

ClampingLoad

hL

2δ

a

Technology News September Layout_Layout 1 8/9/11 9:59 AM Page 50

51WELDING JOURNAL

A Solder Glass Frit for JoiningAlumina Ceramic

Despite the relatively low strength ofjoints, glass solders have many advantagesfor bonding ceramics. These include thefollowing: a) chemical compatibility with abase ceramic material; b) comparable co-efficient of thermal expansion; c) goodwetting and adherence to ceramics; and d)melting, viscosity, and flowability con-trolled in a wide range.

Authors from the Singapore Instituteof Manufacturing Technology have stud-ied the process of bonding Al2O3 ceramicplates using Schott® Solder Glass GO17-393 and measured bonding strength de-pending on surface treatment, spreading,and voids in the glass (Ref. 5).

Soldering was carried out in a vacuumfurnace at 425°–575°C (795°–1067°F) for5–25 min under pressure 5 kg. Surfacetreatment with phosphoric acid providedthe best conditions of wetting ceramic re-sulting in a contact angle of 10 deg com-pared to 22 deg of the alumina ceramic asreceived and 17 deg of ceramic treatedwith sulfuric acid.

However, it was found that surfacetreatment is not necessarily positive inpromoting bonding strength. In oppositeto metal solders, the capillary effect doesnot work effectively during ceramic bond-ing by glass solders because the bondingstrength is not governed by wetting thecontact angle. Ceramic joints in “as-re-ceived” conditions exhibited significantlyhigher strength, while ceramic jointstreated for the lowest contact angle hadthe lowest tensile strength.

Testing results showed that bondingstrength of joints is mainly governed by thesoldering temperature and time, and sur-face roughness of ceramic. The lower bond-ing temperature of 425°C provides the high-est tensile strength of joints, while rising thetemperature to 575°C decreased strengthfor about 40%. Besides, samples bondedabove 500°C displayed porous joints.

Au-Sn-In Solder for ProcessingCompatibility with Lead-Free, Tin-Based Solders

Currently, semiconductor devices aresealed using gold-tin solder with the goldcontent ranging 78–81 wt-% and tin con-tent 19–21 wt-%. This Au-Sn eutectic sol-der has been in use for more than 40 years,and has a melting temperature of 280°C(536°F), which is compatible with all tra-ditional Sn-Pb solders that have soldering

and post-sealing temperatures below245°C. Lead-free, Sn-Ag-Cu solders thatcame to the industry in the last decadehave a melting temperature at 217°C andrequire processing at 270°C that is dan-gerously close to the 280°C melting pointof the Au-Sn alloy used for sealing elec-tronic devices.

A new Au-Sn-In solder invented byWilliams Advanced Materials, Inc., Buf-falo, N.Y., has a melting temperature of300°–320°C (572°–608°F) that makes itcompatible with a semiconductor die at-tach and hermetic sealing of electronicpackages after soldering using contempo-rary lead-free solders (Ref. 6).

BRAZING & SOLDERING TODAYTECHNOLOGY NEWS

Aerospace Grade Brazing & WeldingAlloys

Aerospace Grade Brazing & WeldingAlloys

Aimtek is proud to offer a variety of value-added services from custom labeling, to specialized packaging, to onsite equipment training. Our technical Engineering Department and knowledgeablestaff will help meet your standard and custom requirements fromconcept to production. We understand that a small request can make a big difference.

• Powder and Paste• Wire and Foil• Rings and Preforms• Cut Length RodsIN STOCK and waiting for you!

For info go to www.aws.org/ad-index

Technology News September Layout_Layout 1 8/9/11 9:59 AM Page 51

BRAZING & SOLDERING TODAY

SEPTEMBER 201152

The solder contains 17.5–20.5 wt-% oftin, 2–6 wt-% of indium, and gold in thebalance; the exemplary solder contains Sn19.3 wt-% and In 4.5 wt-%. Advanta-geously, the new solder permits post seal-ing operations at temperatures greaterthan 270°C (518°F) without reflowing andsubsequent loss of seal integrity.

Modified Water Drop Method ofEvaluating Soldering Fluxes forElectrochemical MigrationPropensity

Electrochemical migration (ECM) is aunique corrosion-related reliability concernin consumer electronic products because itresults from a combination of such factorsas applied electric potential, humidity, andionic contaminants. The traditional tem-perature-humidity-bias (THB) test is long(from 30 to 300 days) and requires a largenumber of samples for statistical evaluationthat increase the cost of testing. The alter-native water drop (WD) method is quickerby a factor of 100 at a fraction of the cost.

However, reproducibility is a problem withthe WD method.

A modified WD method for solderingflux evaluation was developed and testedby Nokia, Irving, Tex. (Ref. 7). Though thescatter in data was significant, this WDtest method can be used to identify fluxesthat performed significantly better thanothers. The following four principles wereselected to provide comparing the relativepropensity of ECM depending on the fluxtype during soldering of printed wireboards: (a) Select different finishes suchas Cu, Ag, and Sn. It was expected thatmore than one metal may participate inthe ECM dendrite formation; (b) select avoltage gradient that is representative ofactual portable consumer electronics, esp.7.5 V/mm; (c) select different fluxes usedin lead-free soldering; and (d) performWD tests using deionized water to rank al-ternatives based on propensity for ECMrelated failure.

Results indicated that a clear rankingwas established among four solderingfluxes. In addition, among the differentmetals, the silver finishing was found to

have the highest ECM propensity acrossall fluxes.

High-Velocity Cold SprayingPowders for Cleaning Surfaceand Applying Brazing FillerMetals onto a Substrate

General Electric Co., Schenectady,N.Y., developed a cost-effective methodfor applying brazing filler metals onto su-peralloy parts of gas turbine engines (Ref.8). Cold gas dynamic spraying (or kineticmetallization) is a process that uses finemetal powders that are accelerated by agas stream and impacted against a surfaceto form a coating. The metal particles col-lide with the surface, resulting in plasticdeformation and bonding of these parti-cles to the substrate and other particles.There is no melting of the particles.

The braze filler metal powder that firstimpacts the substrate acts as a blastingmedia and cleans the surface to be brazedby removing a thin layer of surface mate-rial. The layer removed is more than zeroand less than 1 micron, but it is sufficientto substantially remove any surface oxides.

After the braze filler powder removesthe oxide layer, the powder begins to ad-here and bond to the surface.

For example, a braze alloy layer wasformed using Ni-7Cr-3Fe-3B-4.1Si pow-der at an argon spray temperature ofabout 315°C (600°F). The formed layerwas about (80 microns) 0.003 in. thick.The formed layer had no oxides betweenthe braze alloy layer and the superalloysubstrate, which was then successfullybrazed in a vacuum furnace.

Vacuum Brazing of Carbon-FiberComposites with Aluminum Filler Metals

Brazing of carbon-fiber composited ata low temperature can be done using alu-minum filler metals. This process wastested, and the strength of brazed jointswas measured in Shandong University,Jinan, China (Ref. 9). Pure aluminum andAlloy Al-5Ti-1B (wt-%) were applied asbrazing filler metals. Vacuum brazing ofCf/C composite with aluminum was car-ried out at 700°C (1292°F) and 730°C(1346°F), while brazing with the Al-5Ti-1B filler metal occurred at 720°C(1328°F) and 750°C (1382°F) for 20–30min. Flat parts to be joined were com-pressed at 0.375 MPa (0.054 ksi) duringheating and cooling.

Aluminum filler metals exhibited sat-

TECHNOLOGY NEWS

Lower the Cost

...Not the Quality

Our new braze filler metals cost less than nickel-based

filler metals, braze with similar cycles and produce

joints with equal strength and corrosion resistance. For

more information, contact our Braze Product Manager

at +1 248 280 3113 or Deni.Fortuna@Sulzer.com.

Sulzer Metco (US) Inc.1101 Prospect Ave

Westbury NY 11590

U.S.A.

Tel.: +1 516 334 1300

Fax: +1 516 338 2414

www.sulzermetco.com

NEW! Low Cost AMDRY® Braze Filler Metals for Applications

For info go to www.aws.org/ad-index

Technology News September Layout_Layout 1 8/9/11 10:00 AM Page 52

BRAZING & SOLDERING TODAY

53WELDING JOURNAL

isfactory wetting of the base material at atemperature above 700°C, but also poorflowability. However, diffusion of liquidfiller metals into porous carbon compos-ite under pressure resulted in the forma-tion of solid, dense joint metal character-ized by shear strength 9.1–9.4 MPa (1.3ksi) for Al filler metal, and 10.6 MPa (1.5ksi) for Al-5Ti-1B filler metal.

Increasing the brazing temperaturenot only improves the fluidity of brazingalloys, but it also prevents coarseninggrains in the joint microstructure andimproves the quality of brazed joints.Slightly lower strength of aluminumbrazed joints can be explained by a biggerthickness of the joint zone, about 200microns, while joints brazed with the Al-5Ti-1B alloy had a thickness of only 60microns. Boron proved to be a grainrefiner that also resulted in better qualityof the joint metal.♦

References

1. Verduzco, J. A., Gonzalez-Sanchez,

J., Verduzco, V. H., Solis, J., and Lemus-Ruiz, J. 2010. Microstructure and electro-chemical properties of the bonding zoneof AISI 316L steel joined with a Fe-basedamorphous foil. J. Mater. Process. Technol.210(8): 1051–1060.

2. Hirao, H., Yamaji, N., and Murai, T.2010. Surface treating agent for copper orcopper alloy and use thereof. Interna-tional Patent WO 2010/024472 A1.

3. Li, J. F., Agyakwa, P. A., and John-son, C. M. 2011. Inrerfacial reaction inCu/Sn/Cu system during the transient liq-uid phase soldering process. Acta Materi-alia 59(3): 1198–1211.

4. Philips, N. R., He, M. Y., and Evans,A. G. 2008. A wedge fracture toughnesstest for intermediate toughness materials;Application to brazed joints. Acta Materi-alia 56: 4593–4600.

5. Sun, Z., Pan, D., Wei, J., and Wong,C. K. 2004. Ceramic bonding using a sol-der glass frit. Journal of Electronic Materi-als 33(12): 1516–1523.

6. Lichtenberger, H. 2010. Gold-tin-in-dium solder for processing compatibility

with lead-free tin-based solder. WorldPatent WO 2010/008752.

7. Canumalla, S., Ludwig, K., Pedigo,R., and Fitzgerald, T. 2006. A study ofranking of commercial fluxes for electro-chemical migration propensity for Cu, Snand Ag surface finishing. Proc. of 56thElectronic Components and TechnologyConf., IEEE, 625–631.

8. Dighe, M., and Thyssen, J. R. 2008.Method of applying braze filler metalpowders to substrate for surface cleaningand protection. U.S. Patent Application2008/0160332.

9. Chen, J., Xu, G., Geng, H., andChen, G. 2007. Study on vacuum brazingof Cf/C composites. China Welding 16(4):56–59.

TECHNOLOGY NEWS

Information provided by ALEXANDER E. SHAPIRO (ashapiro@titanium-braz-ing.com) and LEO A. SHAPIRO, Tita-nium Brazing, Inc., Columbus, Ohio.

TECHNICAL TRAINING The Hobart Institute of Welding Technologyoffers our comprehensive Technical Trainingcourses through the year! Upcoming dates:

Prep for AWS Certified Welding Supervisor ExamSeptember 19 - 23

Prep for AWS Welding Inspector/Educator ExamOctober 3 – 14 December 5 - 16

Visual Inspection November 21 - 22

Welding for the Non WelderNovember 14 - 17

Arc Welding Inspection & Quality ControlSeptember 26 - 30 November 28 – December 2

Liquid Penetrant & Magnetic Particle InspectionOctober 24 - 28

1-800-332-9448or visit us at www.welding.org

for more information.© 2011 Hobart Institute of Welding

Technology, Troy, OHSt. of Ohio Reg. No. 70-12-0064HT

For info go to www.aws.org/ad-index For info go to www.aws.org/ad-index

Technology News September Layout_Layout 1 8/9/11 10:00 AM Page 53