Dip coating process.pdf

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2. ▣Dipcoatingreferstotheimmersingofasubstrate
intoatankcontainingcoatingmaterial,removing
thepiecefromthetank,andallowingittodrain.The
coatedpiececanthenbedriedbyforce-dryingor
baking.Itisapopularwayofcreatingthinfilm
coatedmaterialsalongwiththespincoating
procedure.

3. Thedipcoatingprocesscanbe,generally,separatedinto3
stages:
▣Immersion:thesubstrateisimmersedinthesolutionof
thecoatingmaterial ataconstantspeedpreferably
judderfree
▣Dwelltime:thesubstrateremainsfullyimmersedand
motionlesstoallowforthecoatingmaterialtoapply
itselftothesubstrate
▣Withdrawal:thesubstrateiswithdrawn,againata
constantspeedtoavoidanyjudders.Thefasterthe
substrateiswithdrawnfromthetankthethickerthe
coatingmaterialthatwillbeappliedtotheboard.

5. Fig.2:Gelationprocessduringdipcoatingprocess,
obtainedbyevaporationofthesolventandsubsequent
destabilizationofthesol

6. ▣Owingtoitssimplicity,thismethodlendsitselfto
automation.Filmthicknessiscontrolledbycoating
viscosityandrate ofwithdrawalfromthetank.Dip
tankscomeinallshapesandaresizedtoaccommodate
thelargestobjecttobecoated.
▣Dipcoatinghasitsdrawbacks,including:lightparts
tendtofloatandfallfromtheconveyor;filmthickness
canvaryfromtoptobottom("wedgeeffect");fatty
edgesdeveloponthebottomofpartsasexcesscoating
drains;andrefluxingbythesolventvaporsabovethe
tankremovessomeofthecoating

7. ▣Dipcoatingprocessesareusedforplateglassfor
solarenergycontrolsystems(Calorex®)andanti-
reflectivecoatings(Amiran®)onwindows.Thedip
coatingtechniqueisalsoappliedforoptical
coatings,e.g.onbulbs,foropticalfiltersor
dielectricmirrorsbyvariousSMEsandother
companies,fabricatingmultilayersystemswithup
to30or40coatingswithveryhighprecision.

8. ▣WhatisElectrodeposition?
▣Electrodepositionistheprocessofcoating
athinlayerofonemetalontopofa
differentmetaltomodifyitssurface
properties.
▣Donetoachievethedesiredelectricaland
corrosionresistance,reducewear&
friction,improveheattoleranceandfor
decoration.
▣E.D.isasurfacecoatingmethodthatforms
anadherentlayerofonemetalonanother.

10. ▣Electrodepositionisakeymethodformakingthe
materialsusedincomputerchipsandmagneticdata
storagesystems;everydayithelpslowerthecost
andimprovetheperformanceofourinformation
society.
▣However,electrodepositionisalsoemergingasa
uniquelycapablemethodformakingmaterialsand
structuresneededforananotechnology-and
nanobiotechnologybasedfuture.
▣Italsoprovidessomeuniqueopportunitiesfor
directlywritingmaterialsontoasurfacewithout
goingthroughthe photoresistmaskingstepsthatare
usedinconventionalelectrochemical
microfabrication.

11. Electrodepositionhasthreemainattributesthatmakeit
sowellsuitedfornano-,bio-and
microtechnologies:
•Itcanbeusedtogrowfunctionalmaterialthrough
complex3Dmasks.
•Itcanbeperformednearroomtemperaturefrom
water-basedelectrolytes.
•Itcanbescaleddowntothedepositionofafew
atomsoruptolargedimensions.

12. ▣Automotiveparts
▣Printedcircuitryandelectricalcontacts
▣Generalengineeringcomponents
▣Gold-SilverwaresandJewelry
▣MusicalInstrumentsand
▣TrophiesSoftmetalgaskets
▣Anti-seizebearings
▣Decorativedoor,light&bathroom
fittings
▣ProductionofmicropartsforMEMS
(MicroElectroMechanicalsystems)