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Piezoelectric Piezoelectric Materials Materials Derek Sanderson Derek Sanderson Tulane University Chemical Tulane University Chemical Engineering Engineering Advisor: Prof. Keith Bowman Advisor: Prof. Keith Bowman

Piezoelectric Materials Derek Sanderson Tulane University Chemical Engineering Advisor: Prof. Keith Bowman

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Piezoelectric Piezoelectric MaterialsMaterials

Derek SandersonDerek SandersonTulane University Chemical EngineeringTulane University Chemical Engineering

Advisor: Prof. Keith BowmanAdvisor: Prof. Keith Bowman

Cancerous Tissue AblationCancerous Tissue Ablation

IdeaIdea array of ultrasound array of ultrasound

transducerstransducers concentrate energyconcentrate energy destroy cancerous tissuedestroy cancerous tissueNeedsNeeds ablation strength pulseablation strength pulseRestrictionsRestrictions close proximityclose proximity small sizesmall size internal body tempinternal body temp

Perovskite StructurePerovskite Structure

Simple cube of A’s + face-Simple cube of A’s + face-centered C’s + body-centered centered C’s + body-centered BB

AA BB CCPbPb2+2+ (Zr/Ti)(Zr/Ti)4+4+ OO33

2-2-

cubiccubic central B-site cationcentral B-site cation paraelectricparaelectric not lowest energynot lowest energy

tetragonal/rhomb.tetragonal/rhomb. shifted B-site cationshifted B-site cation ferroelectricferroelectric lower energylower energy

MicroscopicMicroscopic

cubic structure at cubic structure at high temp.high temp.

cooling below Curie cooling below Curie temp. (Ttemp. (Tcc))

tetra./rhomb.tetra./rhomb. non centrosymmetricnon centrosymmetric c/a < 1.005c/a < 1.005

MacroscopicMacroscopic

neighboring dipoles neighboring dipoles align to form align to form domainsdomains

6 possible domains 6 possible domains per grainper grain

infinite possible infinite possible domains per species domains per species random random orientations orientations no net no net dipole dipole not not piezoelectricpiezoelectric

PolingPoling

strong field appliedstrong field applied field removed – net dipole recedes slightlyfield removed – net dipole recedes slightly not all domains within a grain will switchnot all domains within a grain will switch

P

Poling cont’d- XRDPoling cont’d- XRD

Poled

Tetragonal Rhombohedral

(111)

{111}

{111}(111)

Unpoled

1:31:2

HysteresisHysteresis Initial polarization Initial polarization

(virginal)(virginal) saturation polarizationsaturation polarization remanent polarizationremanent polarization shows a barrier in shows a barrier in

displacement of B-cationdisplacement of B-cation proof of mechanism for proof of mechanism for

piezoelectricitypiezoelectricity application of AC causes application of AC causes

vibrationvibration

Hysteresis curve for Philips PXE 52

Piezoelectricity Piezoelectricity

Direct EffectDirect Effect mechanical strain mechanical strain electrical pulse electrical pulse

Sensors- proportional responseSensors- proportional response force, engine knocking, crash, microphonesforce, engine knocking, crash, microphones

Generators- conversion of energyGenerators- conversion of energy ignitersigniters

Converse EffectConverse Effect electrical pulse electrical pulse mechanical strain mechanical strain

Actuators- proportional responseActuators- proportional response fuel injection valve, speakersfuel injection valve, speakers

Transducers- conversion of energy (high intensity ultrasound)Transducers- conversion of energy (high intensity ultrasound) medical imagingmedical imaging tissue ablationtissue ablation

PMN-PZTPMN-PZT

Pb (Mn,Nb) OPb (Mn,Nb) O33 – Pb (Zr,Ti) O – Pb (Zr,Ti) O33

(soft)(soft) (hard) (hard)

xPMN-(1-x)PZT ceramic systemxPMN-(1-x)PZT ceramic system No “mean value theorem”No “mean value theorem”

EquipmentEquipment

Berlincourt meter- dBerlincourt meter- d3333 tester tester

Pennebaker Model 8000Pennebaker Model 8000 design and operationdesign and operation

SetupSetup

Set ParametersSet Parameters tightness of clamptightness of clamp: 105: 105oo

calibrationcalibration: set for post-: set for post-warmingwarming

interval time (min):interval time (min): 1,5,15,60 for 30 sec.1,5,15,60 for 30 sec.

cooling timecooling time

VariablesVariables warming timewarming time sample thickness, weight, sample thickness, weight,

atmosphere atmosphere

d33 value vs. tightness of brass screw

0

20

40

60

80

100

120

-300 -200 -100 0 100 200 300 400

Degrees of turn from standardd

33 (

pC

/N)

ResultsResultsLiNbO3

No warming

95

100

105

110

115

120

125

0 50 100 150 200

time (min)

d3

3 (

pC

/N)

LiNbO3Warmed 3 hrs.

100

105

110

115

120

125

0 50 100 150 200

Time (min)

d3

3 (

pC

/N)

ResultsResults

LiNbO3warmed 2.5 hours with diff. sample

100

100.5

101101.5

102

102.5

103

103.5104

104.5

105

0 10 20 30 40 50 60 70

time (min.)

d33

(p

C/N

)

ResultsResults

k270-med. Hardno warming

200

250

300

350

400

0 10 20 30 40 50

time (min.)

d33

(p

C/N

)

ResultsResults

k350- soft PZTno warming up

260

270

280

290

300

310

320

0 10 20 30 40 50

time (min.)

d3

3 (

pC

/N)

k700- very soft PZT #1no warming (smaller cooling time)

280

300

320

340

360

380

400

0 10 20 30 40 50

time (min.)

d33 (

pC

/N)

k700- very soft PZT #1 no warming (calib. 3.06)

280

300

320

340

360

380

400

0 10 20 30 40 50

time (min.)

d3

3 (

pC

/N)

ResultsResults

Current TheoryCurrent Theory

Possible ExplanationsPossible Explanations• operator erroroperator error

• reproducedreproduced

• equipment errorequipment error• unknown phenomenonunknown phenomenon

Current TheoryCurrent Theory

Equipment ErrorEquipment Error Values of d33 are significantly lower (up to 50%) of Values of d33 are significantly lower (up to 50%) of

reported values by Keramos.reported values by Keramos. Keramos has noticed the same decrease but not Keramos has noticed the same decrease but not

further investigatedfurther investigated Tests to be conducted at Keramos with 2 different Tests to be conducted at Keramos with 2 different

models of Berlincourt metermodels of Berlincourt meter

Future WorkFuture Work

• Conclude decreasing piezoelectric Conclude decreasing piezoelectric constant due to equipment errorconstant due to equipment error

• Determine cause of the defectDetermine cause of the defect

• Prepare method of obtaining accurate Prepare method of obtaining accurate d33 values with current Pennebaker d33 values with current Pennebaker modelmodel

AcknowledgementsAcknowledgements

Dr. Keith BowmanDr. Keith Bowman Thomas KeyThomas Key Piezo Technologies- Keramos DivisionPiezo Technologies- Keramos Division NSF REU GrantNSF REU Grant

Questions?Questions?