Benkler, M.

Greiner, T.

Hanemann, T.

Medesi, A.

Megnin, C.

English

KITopen

Anna Medesi Albert-Ludwigs-University of Freiburg Department of Microsystems Engineering (IMTEK)  Laboratory for Material Process Technology Low Temperature Sintering of PZT Phase diagram PZT                                        (Moulson/ Herbert, Electroceramics) PZT 2 Anna Medesi Power MEMS 2014       Pb(ZrxTi1-x)O3   Solid solution of PbZrO3 and PbTiO3  Ferroelectric functional ceramic  Properties sensitive to Zr/Ti ratio  Largest electromechanical coupling factor at the MPB:  Zr / Ti  =  52 / 48 Ferroelectric Pyroelectric Piezoelectric Dielectric MPB Application using PZT films 3 Anna Medesi Power MEMS 2014      Actuators   Micromotors  Micropumps      Sensors   Displacement sensors  Proximity sensors  Pressure sensors  Force sensors      Transducers   Lamb wave pumps  Energy harvesters      Capacitors   Ferroelectric RAMs PICMA Stack Actuator (PI Ceramic GmbH) Energy Harvester V25W (Mide Technology Corporation)  Pressure Sensor (SINTEF, Norway)  FeRAM Device (Fujitsu Semiconductor Europe) 4 Anna Medesi Power MEMS 2014 Fabrication of PZT films      Thin films  <  3µm  Deposition on glass/silicon/metal substrates  CSD, CVD, PLD, Sputtering, EPD      Thick films  > 50 µm   No need for a substrate  Tape casting methode   uni- / bimorph multimorph C. Eichhorn, 2011  MULTILAYER PIEZOELECTRIC BENDING TRANSDUCER Ceramic Multilayer Technology 5 Anna Medesi Power MEMS 2014 Powder Slurry Green Tape Single Layers Metallized Layers Green                 Multilayer Stack Co-fired                 Multilayer Stack TSINTER TDEBINDING NEW:   Piezoelectric Multilayer with Ag-Electrodes  Challenge: Material Compatibility 6 Anna Medesi Power MEMS 2014 TSINTER (PZT)  ≈ 1200 °C Tm (Ag)  =  961 °C PZT-ML are fabricated with  high temperature stable inner electrodes from  Pt  or Ag/Pd alloys  Metall prices [US-$/oz] Ag  14.77   Pd 703.87 Pt 1,100.81 Source: finanzen.net, 18.11.2014 Ag can not be co-fired together with PZT Low Temperature Co-fired Piezo Ceramic Further Benefits of PZT-based LTCC 7 Anna Medesi Power MEMS 2014 MATERIAL COMPATIBILITY STABILIZATION OF ELECTROMECH. PROP. REDUCTION  OF   PROCESS COSTS Co-firing of     Hybrid ML structures       with  integrated  LTCC-Layers  Reduction of evaporation     of volatile PbO out of PZT during the sintering process, so that the subsequent piezoelectric components become more reliable Less environmental pollution             through less evaporation        of Pb-compounds  Less energy consumption                  through lowered                   sintering temperatures Approaches for Lowering the TSINTER 8 Anna Medesi Power MEMS 2014 1    Hot-pressing in oxygen 2    Vacuumed-air-venting process  3    Using fine ball-milled powders 4    Using bimodal powders 5    Liquid Phase Sintering Technology  17.12.2014 Anna Medesi - 9 - 1. Incorporation of low-melting        metal oxides into the ‘green’       unsintered ceramic 2. Formation of a liquid-phase           at temperatures about 600 to       800 °C 3. Acceleration of densification      through facilitating the           PZT particles rearrangement Liquid Phase Sintering Technology pore sintering aid PZT 4. Formation of sintering necks     with subsequent grain growth Commercial Ferroelectric Hard PZT 10 Anna Medesi Power MEMS 2014      PIC 181 (PI Ceramic)    Withstands high mechanical and electrical stresses   Properties change only hardly in dynamic long-term operations   Relatively low permittivity   High electromechanical coupling factors   Very low dielectric losses   Very high mechanical quality factor  TC 330 °C ε33T /ε0 1200 ε11T /ε0 1500 tan δ < 3 · 10-3 k31 0.33 k33 0.66 kp 0.56 d31 -120  pC/N d33 265  pC/N Qm 2000 well suited for vibration energy harvesters driven in continuous use       in resonance mode with only low intrinsic warming of the component Investigated Sintering Aids 11 Anna Medesi Power MEMS 2014 1 2 3 4 5 6 7 8 9 10 Aid: Cu2O ∙ PbO (4:1) PbO ∙ WO3 (5:1) Li2CO3 ∙ Bi2O3 ∙ CuO (1:1:4) CuO Tm: 680°C 730°C no PD available 1326°C Lit.: Corker et al.,                  2000, Denmark Vötsch et al., 2007, Austria  Nielsen et al., 2002, Slovenia Yoo et al., 2004, Korea                            Wang et al., 2000, Japan Nam et al., 2011, Korea Lee et al., 2000, Korea Aid: Li2CO3 Li2O Bi2O3 V2O5 MnO2 PbO Tm: 720°C 1427°C 817°C 690°C 535°C 888°C Lit.: Han et al., 2011, Korea       Yoo et al., 2005 Japan            Lee et al., 2005, Korea  Jin et al., 2003, Korea Wang et al., 1992, China Seo et al.,           2011, Korea Corker et al., 2000, Denmark Ahn et al.,          2006, Korea Preparation and Characterization of 20 different PZT-Sintering Aid Combinations  12 Anna Medesi Power MEMS 2014 Micro-structure Thermal behavior Mechanical stability Piezoelectric properties … for each SA                in 2 volume fractions:            2 vol.% and 5 vol.% charge constant d33 porosity density breaking strength σ0 TSINTER Thermal Behavior 13 Anna Medesi Power MEMS 2014 Source: TA Instruments Dilatometry: Detection of pellet shrinkage Displacement sensor      Transmission rod    Pellet Length ↓ with T ↑ Result for the composition: PZT +                 2 vol.% Li2CO3 TSINTER  =  814 °C LBCu Bi2O3 PbO·WO3 Cu2O·PbO PbO Li2CO3 Li2O CuO V2O5 Mn2O Thermal Behavior 14 Anna Medesi Power MEMS 2014 Lowest  TSINTER: PZT +  2 vol.% LBCu Microstructure 15 Anna Medesi Power MEMS 2014 LBCu PbO·WO3 PbO CuO V2O5 Li2O Li2CO3 Cu2O·PbO Bi2O3 Mn2O Almost 100% of the theoretical density of PZT sintered @ 1200 °C:  PZT +  5 vol.% LBCu sintered @ 900 °C ρrel  /  % 17.12.2014 Anna Medesi - 16 - Microstructure PZT PZT +                                 5 vol.% PbO·WO3 PZT +                                 5 vol.% LBCu porous dense @ 900 °C Mechanical Stability 17 Anna Medesi Power MEMS 2014 Measured: Breaking strength of each specimen                           Performed: 3-point-bending tests according to DIN EN 843-1  on  > 10 specimens for each PZT-SA composition  Evaluated:  Characteristic breaking strengths  with   Weibull statistic     using Maximum-Likelihood-Methode Mechanical Stability 18 Anna Medesi Power MEMS 2014 𝜎𝑓 𝜎0 Mechanical Stability 19 Anna Medesi Power MEMS 2014 LBCu CuO V2O5 PbO·WO3 Bi2O3 Cu2O·PbO PbO Li2CO3 Li2O Mn2O σ0  /  MPa Most stable films:  PZT +  5 vol.% LBCu Very brittle ! Piezoelectric Properties 20 Anna Medesi Power MEMS 2014 d33  /  pC/N CuO LBCu PbO·WO3 Cu2O·PbO Li2CO3 V2O5 Li2O Bi2O3 PbO Mn2O Nearly the piezoelectricity of PIC 181 (d33 = 265 pC/N)      is reached:  PZT +  5 vol.% CuO Conclusion 21 Anna Medesi Power MEMS 2014  We fabricated piezoelectric ML with inner electrodes from pure Ag   10 sintering aids for hard PZT have been investigated    Mechanical stability  I  microstructure  I  thermal behavior  I  piezoel. prop.   of  low temperature sintered thick films (t ≈ 100 µm) were studied   Films made of PZT + LBCu  sintered @ 900 °C shows            Addition CuO has a positive effect on the piezoelectric properties of PZT  a) Lowest TSINTER  (641°C) b) Highest density   (ρrel = 97%) c) Highest mechanical stability   (σ0  = 77 MPa) d) High piezoelectric properties   (d33  =  246 pC/N) 22 Anna Medesi Power MEMS 2014 Thank you  for  your kind attention! Co-Casting – The New Manufacturing Process 23 Anna Medesi Power MEMS 2014 For film thicknesses < 50 µm required green tape thicknesses:  < 80 µm Limit of accurately metallizing and stacking is reached Co-casted piezoelectric ML with interdigital electrode structure  Electrode thickness:  5-10 µm  Ceramic layer thickness:  30-70 µm 

Low temperature sintering of PZT

https://publikationen.bibliothek.kit.edu/240097923/3816686

Low temperature sintering of PZT

Abstract

Similar works

Full text

Available Versions

KITopen