“Soldering and Brazing” comparing with Diffusion bonding, Hot pressing, and Solid phase bonding. Dr. Kunio TAKAHASHI - Associate professor, Dept. of International Development Engineering, Tokyo Institute of Technology ,Tokyo 152-8552, Japan Phone/Fax:+81-3-5734-3915 - PowerPoint PPT Presentation
“ “ Soldering and Brazing” Soldering and Brazing” comparing with comparing with Diffusion bonding, Hot Diffusion bonding, Hot pressing, pressing, and Solid phase bonding and Solid phase bonding Dr. Kunio TAKAHASHI Dr. Kunio TAKAHASHI - Associate professor, - Associate professor, Dept. of International Development Dept. of International Development Engineering, Engineering, Tokyo Institute of Technology Tokyo Institute of Technology ,Tokyo 152-85 ,Tokyo 152-85 52, Japan 52, Japan Phone/Fax:+81-3-5734-3915 Phone/Fax:+81-3-5734-3915 E-Mail:[email protected]E-Mail:[email protected]http://www.ide.titech.ac.jp/~takahak/ http://www.ide.titech.ac.jp/~takahak/
Transcript
““Soldering and Brazing” Soldering and Brazing” comparing withcomparing with Diffusion bonding, Hot pressing, Diffusion bonding, Hot pressing,
and Solid phase bondingand Solid phase bonding
Dr. Kunio TAKAHASHIDr. Kunio TAKAHASHI - Associate professor,- Associate professor,
Dept. of International Development Engineering,Dept. of International Development Engineering,Tokyo Institute of TechnologyTokyo Institute of Technology,Tokyo 152-8552, Japan,Tokyo 152-8552, JapanPhone/Fax:+81-3-5734-3915Phone/Fax:+81-3-5734-3915E-Mail:[email protected]:[email protected]://www.ide.titech.ac.jp/~takahak/http://www.ide.titech.ac.jp/~takahak/
Prior to this lecture...Prior to this lecture...Activities of Japanese welding Activities of Japanese welding
communitycommunity
Organizations and their rolesOrganizations and their roles
Japanese system of education and Japanese system of education and certificationcertification
Movement around Asian Welding FederationMovement around Asian Welding Federation
About About lecturer’s ...lecturer’s ... Back groundBack ground
welding ( what is this ? )welding ( what is this ? ) Tokyo Institute of technologyTokyo Institute of technology
http://www.titech.ac.jp/http://www.titech.ac.jp/
Department of International Development Eng.Department of International Development Eng.NetworkNetwork beyondbeyond the the borderborder of of engineering fieldengineering field(community)(community) nationnationhttp://www.ide.titech.ac.jp/http://www.ide.titech.ac.jp/
Welcome to JapanWelcome to JapanAlready, you have joined to Already, you have joined to our Networkour Network..
Welding Technology, Welding Technology, as ”Inter-Field” Engineeringas ”Inter-Field” Engineering based onbased on Plasma physicsPlasma physics Electronics/Electrical Eng.Electronics/Electrical Eng. Power SourcePower Source Control Control (“self-controlled” is the best) (“self-controlled” is the best) = = Heat sourcesHeat sources Thermal Eng.Thermal Eng. Fluid dynamicsFluid dynamics Material scienceMaterial science Fracture mechanicsFracture mechanics
Physics of phenomenaPhysics of phenomena StandardStandard IndustryIndustry
About this lecture “Brazing and Soldering About this lecture “Brazing and Soldering …”…”
Basic knowledgeBasic knowledge based on physics based on physics– PhenomenaPhenomena– Comparison with other welding processesComparison with other welding processes– What is and what is not clarified, theoretically ?What is and what is not clarified, theoretically ?– Recent progresses for physical understanding.Recent progresses for physical understanding.so,so,
You will understand...You will understand...– Why and How the process is used ?Why and How the process is used ? Experimental Experimental
trainingtraining– How the process can be modified ?How the process can be modified ?
Definition of brazing and solderingDefinition of brazing and soldering ExamplesExamples Comparison with other welding Comparison with other welding
processesprocesses Heat sourcesHeat sources Brazing filler metals and soldersBrazing filler metals and solders Fluxes and atmosphereFluxes and atmosphere Set up and joint shapeSet up and joint shape Phenomena in brazing and solderingPhenomena in brazing and soldering
– Wetting ( surface and interfacial tension )Wetting ( surface and interfacial tension )– Conduction of heatConduction of heat– DissolutionDissolution– FlowFlow– DiffusionDiffusion– DeformationDeformation– Oxidation - reduction reactionOxidation - reduction reaction– Solidification -> microscopic structureSolidification -> microscopic structure
ExerciseExercise
Contents Contents ofofthis lecturethis lecture
Please remember in your experimental training (Sept.19 ?)
Definition of the brazing and soldering.Definition of the brazing and soldering.
Joint is Joint is heatheateded distributing distributing filler metalfiller metal between base materials, between base materials, by by capillarycapillary action action below below solidus temperaturesolidus temperature of of base materialsbase materials.. Sometimes the joint is pressed.Sometimes the joint is pressed.
example of brazing example of brazing main engine LE7A main engine LE7A H2A rocket H2A rocket
Filler metalsFiller metals
BrazingBrazingmelting point of filler metal melting point of filler metal >> 723723 K K （ （ 450 450 C, C, 840 840 F F ））
SolderingSolderingmelting point of filler metal melting point of filler metal << 723723 K K （ （ 450 450 C, C, 840 840 F F ））
Capillary actionCapillary action
Wetting phenomenonWetting phenomenon
Surface tensionSurface tensionor or
Surface energySurface energy
A g-C u phase diagram .
Solidus temperatureSolidus temperature
phase diagramphase diagram
– Equilibrium Equilibrium phasephase
– Lever ruleLever rule
Solidus Liquidus
exampleexample
Soldering is key technologySoldering is key technologyin micro-electronics assemblyin micro-electronics assembly
exampleexample
Soldering is key technologySoldering is key technologyin micro-electronics assemblyin micro-electronics assembly
Melting pointMelting pointproblemsproblems in processesin processes almost solve almost solve
dd ViscosityViscosity
Corrosion Corrosion still under R still under R/D/D– Heating ironHeating iron in iron solderingin iron soldering– Solder bathSolder bath in reflow solderingin reflow soldering
exampleexample Al brazingAl brazing
exampleexample Ni brazingNi brazing
exampleexample Ag brazing of Stainless and Ag brazing of Stainless and Ceramics Ceramics
The highest technology is The highest technology is never used for space never used for space development.development.
The highest technology is The highest technology is the the combinationcombination of of conventional technologies.conventional technologies.
OptimizationOptimization & & breakthroughbreakthrough are based on are based on scientific understandingscientific understanding
Comparison with other welding or joining processesComparison with other welding or joining processes
melting base materials melting base materials ex. arc welding, resistance welding, etc…ex. arc welding, resistance welding, etc…
adding molten metals between base materialsadding molten metals between base materialsex. ex. brazingbrazing,, soldering soldering, etc..., etc...
not melting base materialsnot melting base materialsex. solid phase bonding, hot pressing, etc...ex. solid phase bonding, hot pressing, etc...
Diffusion bonding, Hot pressing, Diffusion bonding, Hot pressing, and Solid phase bondingand Solid phase bonding
Samples are Samples are – heatedheated,,
and and – pressedpressed..– Sometimes Sometimes metal metal
sheetsheet is inserted. is inserted.
“filler metal” ? in brazing
Another type of equipmentsAnother type of equipments Hot Isostatic Pressing (HIP)Hot Isostatic Pressing (HIP)
ExampleExample Ni alloyNi alloy
Requirements for joiningRequirements for joining– to bring atoms near stable inter-atomic distanceto bring atoms near stable inter-atomic distance
WettingWetting Heat transfer Heat transfer DissolutionDissolution FlowFlow DiffusionDiffusion DeformationDeformation OxidationOxidation ReductionReduction SolidificationSolidification
Dip brazing/solderingDip brazing/soldering ex. of dip ex. of dip solderingsoldering– Metal bath brazing/soldering Metal bath brazing/soldering (in molten solder bath)(in molten solder bath)– Salt bath brazing/solderingSalt bath brazing/soldering (in flux)(in flux)
Diffusion bonding ( Hot pressing ) ?Diffusion bonding ( Hot pressing ) ?– Liquid phase diffusion bondingLiquid phase diffusion bonding : : iso-thermal solidificationiso-thermal solidification– Eutectic bondingEutectic bonding : no filler metal and: no filler metal and
intent to melt base materiaintent to melt base materialsls
ex. Re-flow used in electronicsex. Re-flow used in electronics
A ssessed P b-Sn phase diagram.Brazing/Soldering temperatureBrazing/Soldering temperature
= Liquidus temp. + = Liquidus temp. + 5050~~100100 K K ( because of viscosity )( because of viscosity )
Brazing filler metals and soldersBrazing filler metals and solders Brazing filler metals in Japanese Industrial Standards (Brazing filler metals in Japanese Industrial Standards (JISJIS))
Fluxes and atmosphereFluxes and atmosphere
FluxesFluxes Shielding Shielding Reduction of surfaces Reduction of surfaces
RequirementsRequirements wettablewettable easily removableeasily removable never harmfulnever harmful
Shielding gasShielding gas
WettabilityWettability
Set up and joint shapeSet up and joint shape
Phenomena in brazing and solderingPhenomena in brazing and soldering Wetting ( Surface and interfacial tension )Wetting ( Surface and interfacial tension ) Conduction of heatConduction of heat DissolutionDissolution FlowFlow DiffusionDiffusion DeformationDeformation Oxidation - reduction reactionOxidation - reduction reaction Solidification -> microscopic structureSolidification -> microscopic structure
Wetting driven by Wetting driven by surface and interfacial tensionsurface and interfacial tension
What determines equilibrium What determines equilibrium ( contact angle, meniscus, etc… ) ?( contact angle, meniscus, etc… ) ?– surface and interfacial tensionsurface and interfacial tension
Young’s equationYoung’s equation coslis
Surface and interfacial tensionSurface and interfacial tension(Surface tension is interfacial tension between material and vacuum.)(Surface tension is interfacial tension between material and vacuum.)
Force on meniscusForce on meniscusLaplace equationLaplace equation
Effect of gravity on meniscus Effect of gravity on meniscus on shape of filleton shape of fillet– Curvature changes with height.Curvature changes with height.
21l
11RR
P
Surface (interfacial) tensionSurface (interfacial) tension and Surface (interfacial) energyand Surface (interfacial) energy
Internal energy and entropyInternal energy and entropy
1st law and 2nd law of thermodynamics1st law and 2nd law of thermodynamics
For bulk,For bulk,thereforetherefore
Variables for unit area of surfaceVariables for unit area of surface
For arbitrary area of surface,For arbitrary area of surface,
Therefore,Therefore,
dApdVTdSdU btottot
sbtot UUU sbtot SSS
bbb pdVTdSdU dATdSdU ss
AUU ss ASS
ss
0ssss TdSdUAdATSU
ss TSU ss TdSdU
pTS
s
T
p
dTTU
TTU
TpTSTpUTp
0s
s
ss
1
),(),(),(
Relation betweenRelation betweenSurface (interfacial) Surface (interfacial) tensiontension and Surface (interfacial) and Surface (interfacial) energenergyy
Surface contribution of internal energy is important.Surface contribution of internal energy is important. at 0 K, at 0 K,
T
p
dTTU
TTU
TpTSTpUTp
0s
s
ss
1
),(),(),(
Surface ( interfacial ) entropy
dTTU
T
TS
T
p
0s
s
1
Surface ( interfacial ) tension
Surface ( interfacial ) energy
sU
Theoretical approach forTheoretical approach for Electronic theory Electronic theory surface tension at surface tension at 0 K0 K (quantum (quantum mechanics)mechanics)
SCF-Jellium
Stabilized jellium
Al
ZnMg
Pb
CaLi
Sr
BaNa
K
Rb Cs
Shifted step potential
Effective electron density parameter rm (Bohr)
Surf
ace
ener
gy a
t zer
o te
mpe
tratu
re
s
(mJ/
m2 )
Be
GaCd
InHg
2 3 4 5 6
500
1000
1500
200025003000
100
Shifted step potentialShifted step potentialK.Takahashi, and T.Onzawa,K.Takahashi, and T.Onzawa,Physical Review B, 48, 5689 (1993)Physical Review B, 48, 5689 (1993)
!! No experimental method gives perfect information by itself.!! No experimental method gives perfect information by itself.!! No theory gives perfect information by itself.!! No theory gives perfect information by itself.
Strategy by lecturer for...Strategy by lecturer for...
Diffusion equation for Cartesian coordinate system Diffusion equation for Cartesian coordinate system
2
2
2
2
2
2
zT
yT
xTD
tT
T grad q
TDTcct
T grad div grad div div1
q
c
D
Conduction of heat (2)Conduction of heat (2)
Solutions for special boundary conditionsSolutions for special boundary conditions– Steady state (t=Steady state (t=), one dimensional), one dimensional
– Steady state (t=Steady state (t=), axially symmetric ), axially symmetric
– Steady state (t=Steady state (t=), center symmetric ), center symmetric
02
2
xTD
tT
012
2
rT
rrTD
tT
022
2
rT
rrTD
tT
21)( CxCxT
21 ln)( CrCrT
211)( Cr
CrT
Conduction of heat (2)Conduction of heat (2)
Basic solutions of diffusion equationBasic solutions of diffusion equation– one dimensionalone dimensional area heatingarea heating
for heat input for heat input QQ Q Q ((J/mJ/m))
– two dimensionaltwo dimensional linear heatinglinear heating
Q Q ((J/mJ/m22))
– three dimensionalthree dimensional point heatingpoint heating
Approximation “Liquid is always uniform.”Approximation “Liquid is always uniform.”
DiffusionDiffusion
Fick’s 1st law, Fick’s 2nd law, and Diffusion equationFick’s 1st law, Fick’s 2nd law, and Diffusion equation
Application of basic solutionsApplication of basic solutions
wherewhere
Dtx
DtcC
4exp
4
20
DtxcC
4erf1
20
0
2exp2erf d
-10 0 10X-AXIS
0
0.5
1
Y-A
XIS
2
2
2
2
2
2
zC
yC
xCD
tC
DiffusionDiffusion
When material P is joined with iWhen material P is joined with insert (filler) metal, change in cnsert (filler) metal, change in concentration profiles across booncentration profiles across bond interface.nd interface.
and if and if below eutectic temperature…below eutectic temperature… joint of P and Q at Tjoint of P and Q at T0 0 ,…,… joint of P and Q at <Tjoint of P and Q at <Teutectic eutectic ,…,… Q is inserted,...Q is inserted,... etc...etc...
DtxcC
4erf1s
DeformationDeformation : Deformation around joint: Deformation around joint
Eutectic phase can be seen.Eutectic phase can be seen.
WeaknessWeakness of of low melting point materiallow melting point materialex. Pb-Sn solderex. Pb-Sn solder
CrackingCracking
Thermal effectThermal effect
150 150 C 100 hoursC 100 hours
A ssessed P b-Sn phase diagram.
Brittleness Brittleness of of inter-metallic compoundinter-metallic compoundex. Fe - Alex. Fe - Al Although Al is low melting point Although Al is low melting point
material,...material,...
A ssessed F e-A l phase diagram.
ex. filler metal for Al: Low melting point ex. filler metal for Al: Low melting point precise heat precise heat controlcontrol
A ssessed A l-C u phase diagram.
A ssessed A l-Si phase diagram. A ssessed A l-M g phase diagram.
A ssessed A l-Z n phase diagram.
Weld metal Weld metal solidification cracksolidification crack
ex. Alex. Al
at the at the end of the solidificationend of the solidification,,
the liquid vanish the liquid vanish very quicklyvery quickly
lack of liquidlack of liquid crackcrack
A ssessed A l-Si phase diagram .
ex. Ti - Ti bonding with Cu filmex. Ti - Ti bonding with Cu filmA ssessed T i-C u phase diagram .
Exercise 1Exercise 1Schematically, illustrate a concentration profile at 700 Schematically, illustrate a concentration profile at 700 C C
across the interface of diffusion couple (Ag/Cu), across the interface of diffusion couple (Ag/Cu), considering phase diagram.considering phase diagram.
A g-C u phase diagram .
Exercise 2Exercise 2Cu samples are bonded using insert film of Ag by keeping Cu samples are bonded using insert film of Ag by keeping
joint at 900 joint at 900 C. After liquid metal vanished, the joint was C. After liquid metal vanished, the joint was cooled to room temperature. Schematically, illustrate a cooled to room temperature. Schematically, illustrate a change of concentration profile across the interface.change of concentration profile across the interface.
A g-C u phase diagram .
Exercise 3Exercise 3Choose a percentage of Sn in Pb-Sn solder.Choose a percentage of Sn in Pb-Sn solder.And answer a soldering temperature. And answer a soldering temperature. A ssessed P b-Sn phase diagram.
Exercise 4Exercise 4List up deformation mechanisms for solid phase bonding.List up deformation mechanisms for solid phase bonding.
fin.fin.
ボツボツ
Conduction of heatConduction of heat
Application of basic solutionsApplication of basic solutions– Step distribution in t=0.Step distribution in t=0.
– Area heatingArea heating
– Linear heatingLinear heating
– Point heatingPoint heating
Thermal conductivity, Specific heat, Mass densityThermal conductivity, Specific heat, Mass densityTemperature dependence Temperature dependence Thermal diffusion Thermal diffusion
coefficientcoefficient
Surface and interfacial tensionSurface and interfacial tension(Surface tension is interfacial tension between material and (Surface tension is interfacial tension between material and
vacuum.)vacuum.)
Meniscus between flat planeMeniscus between flat plane
