Lead zirconate titanate PZT

spore: profile
id: lead-titanate-pzt
spore_version: 0.2
family: oxide-ceramics
name: Lead zirconate titanate
abbreviation: PZT
role: piezoelectric ceramic (lead zirconate titanate solid solution, Pb(Zr,Ti)O3)
category: ceramics
type: oxides
summary: |
  PZT is a lead zirconate titanate solid solution, a perovskite oxide ceramic. It turns stress into voltage and voltage into motion, and it has been the most widely used commercial piezoelectric material for about 60 years (Seshadri et al., 2018). PI Ceramic's hard grade PIC 255 has a Curie temperature of 350 degC and a charge coefficient d33 of 400 pC/N. A 2 at% Sm-doped laboratory composition near its Curie point reached 915 pm/V, about twice the value of Nb or La donor dopants. The main drawback is lead: the supplier safety data sheet classifies the powder as a reproductive toxicant.
best_for: Transducers and actuators that need a large piezoelectric response well below the Curie point, where lead content is acceptable
weakest_at: 'Lead content: the supplier SDS classes the powder as a reproductive toxicant, and PI limits operation to 50 % of the Curie temperature'
identity:
  formula: Pb(Zr0.52Ti0.48)O3
  cas: 12626-81-2
  crystal_system: perovskite; tetragonal ferroelectric phase below the Curie point (P4mm at 250 degC in the Sm-doped 50:50 study)
  space_group: P4mm
  source: seshadri2018
  where: Introduction (Zr:Ti 52:48 at the morphotropic phase boundary) and Table 1 (P4mm at 250 degC); CAS number from the Stanford Advanced Materials SDS, section 1
  designations:
    - system: Trade name
      code: PIC 255
      note: hard PZT, printed in a column shared with PIC 252
      source: pi-pzt
      where: Standard Piezoelectric Material Data, column PIC255/PIC252
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - mechanisms
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density, PIC 255 hard PZT
    value: 7.8
    unit: g/cm3
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      note: ceramic density as printed by the maker; not a powder value
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Physical and dielectric properties, Density row
  - benchmark: curie_temperature
    label: Curie temperature, PIC 255 hard PZT
    value: 350
    unit: degC
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Physical and dielectric properties, Curie temperature row
  - benchmark: curie_temperature
    label: Curie temperature, Sonox P4 hard PZT (CeramTec)
    value: 325
    unit: degC
    scope: material
    conditions:
      grade: Sonox P4 (CeramTec Navy Type I hard PZT); a different grade from PIC 255
    method: Value printed in the CeramTec piezoceramic hard materials datasheet
    status: ground
    source: ceramtec-hard
    where: Material characteristics table, Curie temperature Tc row, Sonox P4 column
  - benchmark: dielectric_constant
    label: Relative permittivity in the polarisation direction, PIC 255
    value: 1800
    unit: '-'
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      quantity: eps33T/eps0, measured at 23 degC after polarisation
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Relative permittivity row (in polarisation direction)
  - benchmark: dielectric_constant
    label: Relative permittivity in the polarisation direction, Sonox P4 (CeramTec)
    value: 1300
    unit: '-'
    scope: material
    conditions:
      grade: Sonox P4
      quantity: e33T/e0 (free dielectric constant)
    method: Value printed in the CeramTec piezoceramic hard materials datasheet
    status: ground
    source: ceramtec-hard
    where: Dielectric properties table, relative permittivity e33T/e0, Sonox P4 column
  - benchmark: dissipation_factor
    label: Dielectric loss factor, PIC 255
    value: 20
    unit: 10^-3
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      note: printed as 10^-3 in the source, so 20 means 0.020
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Dielectric loss factor tan delta row
  - benchmark: piezoelectric_d33
    label: Piezoelectric charge coefficient d33, PIC 255
    value: 400
    unit: 10^-12 C/N
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      test: test pieces to EN 50324-2, values 24 h to 48 h after polarisation at 23 degC
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Piezoelectric charge coefficient d33 row
  - benchmark: piezoelectric_d33
    label: Piezoelectric charge coefficient d33, Sonox P4 (CeramTec)
    value: 310
    unit: 10^-12 C/N
    scope: material
    conditions:
      grade: Sonox P4
    method: Value printed in the CeramTec piezoceramic hard materials datasheet
    status: ground
    source: ceramtec-hard
    where: Electromechanical properties table, charge constant d33, Sonox P4 column
  - benchmark: piezoelectric_d33
    label: Peak d33 of a 2 at% Sm-doped PZT 50:50 sample near the Curie point (first thermal cycle)
    value: 915
    unit: pm/V
    scope: material
    conditions:
      composition: Pb0.97Sm0.02Zr0.5Ti0.5O3, laboratory sample, not a commercial grade
      temperature: near the Curie point, first thermal cycle
      measurement: converse longitudinal piezoelectric coefficient
    method: Peak value reported by the authors for a laboratory sample
    status: ground
    note: A lab result for one doped composition at high temperature, not a rating for PZT in service. After repoling and thermal cycling the same sample reached 583 and then 438 pm/V (see corrosion).
    source: seshadri2018
    where: Abstract; Results, Fig. 1 and Fig. 2 text
  - benchmark: coupling_factor_kp
    label: Planar coupling factor kp, PIC 255
    value: 0.62
    unit: '-'
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Coupling factor kp row
  - benchmark: mechanical_quality_factor
    label: Mechanical quality factor Qm, PIC 255
    value: 80
    unit: '-'
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      note: low Qm means high damping of resonance, which suits pulse-mode transducers
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Mechanical quality factor row
  - benchmark: coercive_field_strength
    label: Coercive field strength, PIC 255
    value: 1.5
    unit: kV/mm
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      temperature: 25 degC
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Coercive field strength row (at 25 degC)
  - benchmark: static_compressive_strength
    label: Static compressive strength, PZT ceramics (PI)
    value: 600
    bound: lower
    unit: MPa
    scope: material
    conditions:
      basis: PI gives one figure for its PZT ceramics as a group, shown as more than 600 MPa; not a per-grade value
    method: Value printed in the PI Ceramic standard material data table, note on compressive strength
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, note 'Static compressive strength' (right-hand column)
  - benchmark: speed_of_sound
    label: Speed of sound, longitudinal (v1E), PIC 255
    value: 2840
    unit: m/s
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      wave: thin-rod longitudinal wave (v1E)
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Speed of sound v1E row
  - benchmark: acoustic_impedance
    label: Acoustic impedance, pressure wave along polarisation, PIC 255
    value: 34.7
    unit: MRayl
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      direction: polarisation direction
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Acoustic impedance Z33 row
  - benchmark: cte
    label: Coefficient of thermal expansion along polarisation, all PZT (PI approximation)
    value: -6
    value_high: -4
    bound: range
    unit: 10^-6/K
    scope: material
    conditions:
      basis: PI approximation stated as valid for all PZT materials, shorted electrodes, polarisation direction
      note: 'negative: the material shrinks slightly as it heats along the polarisation axis'
    method: Approximation printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, notes at right, coefficient of thermal expansion alpha3
  - benchmark: temperature_coefficient_permittivity
    label: Temperature coefficient of permittivity eps33, PIC 255
    value: 3
    unit: 10^-3/K
    scope: material
    conditions:
      grade: PIC 255 (column PIC255/PIC252)
      range: '-20 to +125 degC'
    method: Value printed in the PI Ceramic standard material data table
    status: ground
    source: pi-pzt
    where: Standard Piezoelectric Material Data, Temperature coefficient of eps33T row
corrosion:
  - environment: Thermal cycling to the depoling temperature (laboratory Sm-doped sample, not a commercial grade)
    headline: Heating a doped PZT sample to its depoling temperature and repoling it cut its peak d33 by more than half over three cycles.
    effect: Peak d33 fell from 915 pm/V on the first thermal cycle to 583 pm/V on the second and 438 pm/V on the third. The authors say the sample was not annealed to processing temperature between cycles, so it would not regain full properties, and they suggest changes in phase fraction, domain walls or point defects.
    rating: moderate
    conditions:
      composition: Pb0.97Sm0.02Zr0.5Ti0.5O3
      cycling: heat to depoling temperature, then repole to saturation at room temperature, three times
    source: seshadri2018
    where: Results, Fig. 2 and the paragraph after it
  - environment: Continuous operation at elevated temperature (commercial PZT ceramics)
    headline: PI recommends operation only up to half the Curie temperature, and gives no ageing rate at that limit.
    effect: PI's standard material data table recommends an operating temperature of up to 50 % of the Curie temperature for PZT. The same table gives no time-dependent drift figure for the grades shown, so the long-term loss of response is not quantified here. Published PZT ageing studies that were found could not be opened in this run (see gaps).
    rating: unknown
    conditions:
      basis: manufacturer recommendation for PZT generally, not a test result
    source: pi-pzt
    where: Standard Piezoelectric Material Data, note 'Recommended operating temperature' (right-hand column)
risks:
  hazards:
    - text: 'Supplier SDS (Stanford Advanced Materials, Nov 2022) classifies lead zirconate titanate under Regulation (EC) No 1272/2008 as Repr. 1A (H360: may damage fertility or the unborn child), STOT RE 2 (H373: damage to the reproductive system, blood, brain and endocrine system through prolonged or repeated exposure), and Acute Tox. 4 (H302 and H332: harmful if swallowed or inhaled). Signal word Danger.'
      ghs:
        - H360
        - H373
        - H302
        - H332
      source: stanford-pzt-sds
      where: Section 2 (classification and label elements)
    - text: 'Occupational limits in the same SDS: 0.05 mg/m3 as Pb (US PEL and TLV, 29 CFR 1910.1025) and a biological limit of 30 ug per 100 ml of blood lead.'
      ghs: []
      source: stanford-pzt-sds
      where: Section 8 (control parameters)
  failure_risks:
    - mode: Operation above the recommended temperature limit
      trigger: Use above 50 % of the Curie temperature (350 degC for PIC 255, so above about 175 degC)
      consequence: PI recommends operation up to 50 % of the Curie temperature. The datasheet does not give a response figure above that limit, so the size of the risk is not quantified in this profile.
      severity: moderate
      source: pi-pzt
      where: Standard Piezoelectric Material Data, note 'Recommended operating temperature'
    - mode: Loss of piezoelectric response after thermal cycling
      trigger: Heating a 2 at% Sm-doped PZT 50:50 sample to its depoling temperature and repoling it, three times, without annealing
      consequence: Peak d33 fell from 915 to 583 to 438 pm/V over three cycles, so the first-cycle peak was not repeatable.
      severity: moderate
      source: seshadri2018
      where: Results, Fig. 2
    - mode: Fire releases lead fume
      trigger: The product is involved in a fire
      consequence: The SDS lists lead oxide fume, zirconium oxide and titanium oxides as products of a fire, and says firefighters should wear a self-contained respirator and a fully protective impervious suit.
      severity: high
      source: stanford-pzt-sds
      where: Section 5 (firefighting measures) and Section 10 (hazardous decomposition products)
  side_effects:
    - text: The SDS says not to let the product reach drains, sewage systems or watercourses, and to dispose of waste material under local, regional and national rules.
      affects: Water and soil at the disposal site
      source: stanford-pzt-sds
      where: Section 6 (environmental precautions) and Section 2 (precautionary statement P501)
  handling:
    - text: Keep the container tightly sealed in a cool, dry place with good ventilation, and open it with care. Use a chemical fume hood for dust-generating work (average face velocity at least 100 feet per minute, per the SDS).
      source: stanford-pzt-sds
      where: Sections 7 and 8
    - text: The SDS says the product is for use only by technically qualified individuals.
      source: stanford-pzt-sds
      where: Section 15 (regulatory information)
  mitigations:
    - text: Keep the operating temperature at or below 50 % of the Curie temperature, as PI recommends for PZT.
      source: pi-pzt
      where: Standard Piezoelectric Material Data, note 'Recommended operating temperature'
uses:
  - application: mechanisms
    device: Multilayer piezoelectric stack actuators for spacecraft mechanisms (ground characterisation, not flown)
    example: NASA characterised co-fired multilayer piezoelectric stacks under AC and DC drive at nominal and high temperatures and voltages. Five actuators were driven sinusoidally for up to ten billion cycles. The abstract reports measurements of displacement, impedance, capacitance and leakage current to assess degradation, but gives no degradation result.
    source: nasa-stacks-2008
    where: Abstract (NTRS record 20110013164)
  - application: electronics-and-chips
    device: Transducers and sensors for ultrasonic and other electroacoustic systems
    example: The 2018 Scientific Reports paper calls PZT the most commonly used commercial piezoelectric material for the last 60 years and says it is extensively used in the transducer industry because of its electromechanical sensitivity.
    source: seshadri2018
    where: Introduction, first paragraph
supply:
  - subject: Lead
    producers:
      - country: China
        share_percent: 42.2
        year: 2025
      - country: Australia
        share_percent: 10.7
        year: 2025
      - country: Peru
        share_percent: 6.4
        year: 2025
      - country: United States
        share_percent: 6.2
        year: 2025
    critical_lists:
      - list: USGS 2025 Final List of Critical Minerals (lead added in 2025)
        listed: true
    recycling: 'USGS: about 1 million tons of secondary lead was produced in 2025, equal to 70 % of apparent U.S. consumption, nearly all from old scrap, mostly lead-acid batteries.'
    substitutes:
      - 'USGS: the electronics industry has moved toward lead-free solders. The chapter does not discuss lead in piezoelectric ceramics; lead-free piezo grades are not yet approved for production (see story).'
    source: usgs-mcs2026-lead
    where: World Mine Production and Reserves table, 2025e (shares calculated by Space Mushroom against the printed world total of 4,500 thousand t, which is rounded); Events, Trends and Issues (critical list); Recycling; Substitutes
  - subject: Zirconium
    producers:
      - country: Australia
        share_percent: 33.3
        year: 2025
      - country: South Africa
        share_percent: 22.5
        year: 2025
      - country: Mozambique
        share_percent: 13.3
        year: 2025
      - country: Senegal
        share_percent: 5.8
        year: 2025
    critical_lists: []
    recycling: 'USGS: companies in Oregon and Utah recycled zirconium from new scrap generated during metal production.'
    substitutes:
      - 'USGS: chromite and olivine can substitute for zircon in some foundry applications (not for PZT).'
    source: usgs-mcs2026-zirconium
    where: Zirconium mineral concentrates, mine production table, 2025 (gross weight; shares calculated by Space Mushroom against the printed world total of 1,200 thousand t, which is rounded); Recycling; Substitutes
media: []
documents:
  - title: 'PI Ceramic: Piezo Ceramics Material Data (standard and lead-free tables, revision 08/2024)'
    type: datasheet
    url: https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/technotes_whitepapers/Piezo_Ceramics_Material_Data.pdf
    year: 2024
  - title: 'CeramTec: Piezoceramic Hard Materials datasheet (CA220108/EN/2604/IM)'
    type: datasheet
    url: https://ceramtec-group.com/fileadmin/user_upload/Corporate/11_Downloads/04_Piezo_Ceramics/CeramTec_Datasheet_Piezo_Hard_Materials_EN.PDF
    year: 2026
  - title: 'Stanford Advanced Materials: Safety Data Sheet, PZT (lead zirconate titanate), CAS 12626-81-2'
    type: sds
    url: https://samaterials.com/tds/1697120751-1966-lead-zirconate-titanate-powder-sds.pdf
    year: 2022
  - title: Unexpectedly high piezoelectricity of Sm-doped lead zirconate titanate in the Curie point region (open access)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5841290/
    year: 2018
  - title: Characterization of Piezoelectric Stacks for Space Applications (NASA NTRS 20110013164)
    type: report
    url: https://ntrs.nasa.gov/citations/20110013164
    year: 2008
  - title: 'USGS Mineral Commodity Summaries 2026: Lead'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Zirconium and Hafnium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf
    year: 2026
gaps:
  - No flight, vacuum, radiation or thermal-vacuum result for PZT was found. The only space source is a 2008 NASA ground characterisation of multilayer stacks, whose abstract reports no degradation result.
  - 'The 2017 aging studies of soft and hard PZT (Promsawat et al., Ceramics International) and the related Fe-doped PZT study could not be read: the publisher and the repository returned access blocks. No ageing-rate figure from them is included.'
  - No humidity, electrolyte or moisture-exposure result for bulk PZT was found in a source we could open. Thin-film humidity studies were found but not read in full, so they are not used.
  - Melting point, density and decomposition temperature are 'No data available' in the supplier SDS. The density given is the PI Ceramic figure for PIC 255, not a powder value.
  - Lead content of a typical commercial PZT (weight per cent) is not stated in the SDS we read. A supplier formulation with PbO at 60 to 70 % was seen in another SDS, but it was not read in full and is not used.
  - Lead's EU critical raw materials status was not checked, and the zirconium critical-list status was not checked. Titanium supply is not included; see the titanium profiles.
  - 'RoHS: Directive (EU) 2025/2363 sets exemption 7(c)-I for lead in piezoelectronic devices to expire on 30 June 2027, per the TUV summary. The official EUR-Lex text and the start date were not read.'
  - 'Property names not in property-canon.yaml were written in snake_case: piezoelectric_d33, coupling_factor_kp, mechanical_quality_factor, coercive_field_strength, speed_of_sound, acoustic_impedance, static_compressive_strength, temperature_coefficient_permittivity.'
  - 'Lead-free comparison: PI''s lead-free table gives PIC 753 (KNN) a d33 of 241 pC/N with a Curie temperature of 300 degC, marked preliminary and not approved for production. It is noted in the story but not entered as a property, because it is a different material.'
  - No image was sourced for this profile, so media is empty.
  - Atomic weights in the recipe (Pb 207.2, Zr 91.222, Ti 47.867, O 15.999) are the IUPAC abridged values printed in the Wikipedia element infoboxes read in this run. PubChem element pages returned a browser check, so they were not used.
  - The RoHS expiry (30 June 2027) comes from the TUV Rheinland summary of Directive (EU) 2025/2363 (source key tuv-rohs-2025). The start date and the official text were not read.
sources:
  pi-pzt:
    title: 'PI Ceramic: Piezo Ceramics Material Data (standard and lead-free tables)'
    id: PI Ceramic GmbH, revision 08/2024
    url: https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/technotes_whitepapers/Piezo_Ceramics_Material_Data.pdf
    year: 2024
    kind: datasheet
    license: manufacturer datasheet, cited not reproduced
  ceramtec-hard:
    title: 'CeramTec: Piezoceramic Hard Materials (Sonox P4, PZT401, PZT406, Sonox P8, PZT807)'
    id: CA220108/EN/2604/IM
    url: https://ceramtec-group.com/fileadmin/user_upload/Corporate/11_Downloads/04_Piezo_Ceramics/CeramTec_Datasheet_Piezo_Hard_Materials_EN.PDF
    year: 2026
    kind: datasheet
    license: manufacturer datasheet, cited not reproduced
  seshadri2018:
    title: Unexpectedly high piezoelectricity of Sm-doped lead zirconate titanate in the Curie point region
    id: doi:10.1038/s41598-018-22566-5 (Sci Rep 8, 4120, PMC5841290)
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5841290/
    year: 2018
    kind: paper
    license: open access, Creative Commons (as listed by PMC)
  stanford-pzt-sds:
    title: 'Safety Data Sheet: PZT (Lead Zirconate Titanate), Stanford Advanced Materials, CAS 12626-81-2'
    id: CAS 12626-81-2; revised 29/11/2022
    url: https://samaterials.com/tds/1697120751-1966-lead-zirconate-titanate-powder-sds.pdf
    year: 2022
    kind: datasheet
    license: supplier document, linked not reproduced
  nasa-stacks-2008:
    title: Characterization of Piezoelectric Stacks for Space Applications
    id: NTRS 20110013164 (presented 2008; Sherrit, Jones, Aldrich, Blodget, Bao, Badescu, Bar-Cohen)
    url: https://ntrs.nasa.gov/citations/20110013164
    year: 2008
    kind: report
    license: public domain (NASA)
  usgs-mcs2026-lead:
    title: 'Mineral Commodity Summaries 2026: Lead'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-zirconium:
    title: 'Mineral Commodity Summaries 2026: Zirconium and Hafnium'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  tuv-rohs-2025:
    title: Europe directive (EU) 2025/2363 amending the RoHS directive on exemptions for lead in glass or ceramic components (summary)
    id: Directive (EU) 2025/2363
    url: https://www.tuv.com/regulations-and-standards/en/europe-directive-eu-2025-2363-amending-rohs-directive-on-exemptions-for-lead-in-glass-or-ceramic-components-7-c-i-7-c-ii-7-c-v-7-c-vi.html
    year: 2025
    kind: web
    license: third-party summary, cited not reproduced
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 17
  unreachable: 3
  caveats: 1
  note: 'Written by an AI assistant on 2026-10-26 from pages read in this run. Values come from the PI Ceramic and CeramTec datasheets, a 2018 open-access paper and the Stanford Advanced Materials SDS. Three sources could not be opened: the Promsawat 2017 aging paper (Cranfield repository), the Southampton aging-rate eprint, and PubChem element pages.'
story:
  recipe:
    line: PZT is a solid solution of lead zirconate and lead titanate with the perovskite structure, written Pb(Zr,Ti)O3. The composition used for high piezoelectric response sits at the morphotropic phase boundary, near 52 mol% zirconium to 48 mol% titanium, written Pb(Zr0.52Ti0.48)O3.
    parts:
      - name: Lead
        symbol: Pb
        atoms: 1
        atomic_weight: 207.2
        role: The A-site cation. Lead is the element that carries the toxicity of the material. Samarium is substituted for it in the laboratory donor-doped studies.
      - name: Zirconium
        symbol: Zr
        atoms: 0.52
        atomic_weight: 91.222
        role: A B-site cation. Mixing zirconium with titanium near 52:48 gives the morphotropic phase boundary, where high piezoelectric properties are obtained.
      - name: Titanium
        symbol: Ti
        atoms: 0.48
        atomic_weight: 47.867
        role: The other B-site cation. Together with zirconium it sets the composition at the morphotropic phase boundary.
      - name: Oxygen
        symbol: O
        atoms: 3
        atomic_weight: 15.999
        role: Three oxygen atoms per formula unit.
  risk_groups:
    - title: For people
      level: 0
      verdict: Classed as a reproductive toxicant
      lead: The powder carries serious health hazards on the supplier's safety data sheet, so handle it as lead.
      points:
        - label: The powder
          line: The supplier SDS classes it as Repr. 1A (may damage fertility or the unborn child), STOT RE 2 (damage through prolonged or repeated exposure) and Acute Tox. 4 (harmful if swallowed or inhaled). The signal word is Danger.
        - label: Limits
          line: The US exposure limit is 0.05 mg/m3 as lead, and the blood-lead biological limit is 30 ug per 100 ml.
        - label: In a fire
          line: Lead oxide fume, zirconium oxide and titanium oxides can be released. Firefighters should wear a self-contained respirator.
    - title: Handling and storage
      points:
        - label: Storage
          line: Keep the container tightly sealed, in a cool, dry place with good ventilation.
        - label: Waste
          line: Do not let the product enter drains or watercourses. Dispose of it under local, regional and national rules.
        - label: Heat
          line: PI recommends operating PZT only up to 50 % of its Curie temperature. For PIC 255 that is half of 350 degC, or 175 degC.
  why: PZT is the workhorse of piezoelectric ceramics. It converts a mechanical strain into a voltage and back again, and it has done so in transducers and actuators for about 60 years (Seshadri et al., 2018). Its response is largest near the morphotropic phase boundary, around 52:48 zirconium to titanium, where high piezoelectric properties are obtained. Its drawback is lead, which makes the powder a reproductive toxicant on the supplier's safety data sheet, and which is the reason RoHS needs a special exemption for piezoelectric devices.
  uses:
    - where: Multilayer actuators for spacecraft mechanisms
      line: NASA characterised co-fired multilayer PZT stacks under AC and DC drive at nominal and high temperatures. Five actuators were driven sinusoidally for up to ten billion cycles. The abstract reports no degradation result, so it is a test programme, not a lifetime figure.
    - where: Transducers in the electroacoustic industry
      line: The 2018 paper describes PZT as the most commonly used commercial piezoelectric material for about 60 years and as extensively used in the transducer industry.
  can_do:
    - label: Piezoelectric response
      benchmark: piezoelectric_d33
      value: 400 pC/N
      line: PI's hard grade PIC 255 has a charge coefficient d33 of 400 pC/N. Sonox P4 from CeramTec gives 310 pC/N. In a laboratory Sm-doped composition, the peak near the Curie point reached 915 pm/V on the first thermal cycle.
    - label: Temperature limit
      benchmark: curie_temperature
      value: 350 degC
      line: PIC 255 has a Curie temperature of 350 degC and Sonox P4 of 325 degC. Above that point the crystal changes from the ferroelectric tetragonal phase to a paraelectric cubic phase, as Seshadri et al. describe. PI's recommended operating limit is half the Curie temperature.
    - label: Resonance damping
      benchmark: mechanical_quality_factor
      value: Qm 80
      line: PIC 255 has a mechanical quality factor Qm of 80, which is low, meaning the resonance is well damped. PI describes the family as suited to pulse-mode transducers.
    - label: Density and sound speed
      benchmark: density
      value: 7.8 g/cm3
      line: PIC 255 has a density of 7.8 g/cm3 and a longitudinal sound speed of 2840 m/s. Its acoustic impedance is 34.7 MRayl.
  compare: PZT's main cost is lead. The supplier SDS makes the powder a reproductive toxicant, and the EU's RoHS directive keeps a time-limited exemption for lead in piezoelectric devices. PI Ceramic's lead-free KNN grade PIC 753 gives a d33 of 241 pC/N with a Curie temperature of 300 degC, but PI marks those figures preliminary and says the material is not yet approved for production. The compare rows below use PIC 255 and Sonox P4 as the PZT values.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Curie temperature
      benchmark: curie_temperature
    - label: Piezoelectric d33
      benchmark: piezoelectric_d33
  handling:
    - 'Treat the powder as lead: the SDS classes it as a reproductive toxicant and as harmful by inhalation.'
    - Keep it sealed and dry, and use a fume hood for any work that makes dust.
    - Keep operating temperature to half the Curie temperature or less, as PI recommends.
    - In a fire it can release lead oxide fume, so firefighters need a self-contained respirator.
  good_for:
    - 'Large, stable piezoelectric response: PIC 255 has a d33 of 400 pC/N, with a coupling factor kp of 0.62.'
    - 'Long track record: PZT has been the most widely used commercial piezoelectric material for about 60 years.'
  watch_out:
    - 'Lead content: the powder is classed as a reproductive toxicant and as a source of lead fume in a fire.'
    - 'Ageing and thermal history: a laboratory sample lost more than half its peak d33 over three thermal cycles without annealing.'
    - 'RoHS: the exemption for lead in piezoelectric devices is time-limited, and the TUV summary gives 30 June 2027 as its expiry.'
  verdict: PZT gives the strongest piezoelectric response of the materials in this collection's datasheets, but its lead content is a hazard and a regulatory limit. The lead-free grades PI lists are not yet approved for production, so PZT remains the practical choice for now.