skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Chem-Prep PZT 95/5 for Neutron Generator Applications: Powder Fractionation Study of Production-Scale Powders

Abstract

The Materials Chemistry Department 1846 has developed a lab-scale chem-prep process for the synthesis of PNZT 95/5, referred to as the ''SP'' process (Sandia Process). This process (TSP) has been successfully transferred to and scaled-up by Department 14192 (Ceramics and Glass Department), producing the larger quantities of PZT powder required to meet the future supply needs of Sandia for neutron generator production. The particle size distributions of TSP powders routinely have been found to contain a large particle size fraction that was absent in development (SP) powders. This SAND report documents experimental studies focused on characterizing these particles and assessing their potential impact on material performance. To characterize these larger particles, fractionation of several TSP powders was performed. The ''large particle size fractions'' obtained were characterized by particle size analysis, SEM, and ICP analysis and incorporated into compacts and sintered. Large particles were found to be very similar in structure and composition as the bulk of the powder. Studies showed that the large-size fractions of the powders behave similarly to the non-fractionated powder with respect to the types of microstructural features once sintered. Powders were also compared that were prepared using different post-synthesis processing (i.e. differences in precipitate drying). Resultsmore » showed that these powders contained different amounts and sizes of porous inclusions when sintered. How this affects the functional performance of the PZT 95/5 material is the subject of future investigations.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
820894
Report Number(s):
SAND2003-2007
TRN: US0400540
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Jun 2003
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; PZT; SYNTHESIS; DRYING; FRACTIONATION; NEUTRON GENERATORS; PARTICLE SIZE; PERFORMANCE; POWDER METALLURGY; MICROSTRUCTURE

Citation Formats

MOORE, DIANA L., VOIGT, JAMES A., WATSON, CHAD S., MCKENZIE, BONNIE B., MOORE, ROGER H., HUTCHINSON, MICHAEL A., LOCKWOOD, STEVEN J., and RODMAN-GONZALES, EMILY D. Chem-Prep PZT 95/5 for Neutron Generator Applications: Powder Fractionation Study of Production-Scale Powders. United States: N. p., 2003. Web. doi:10.2172/820894.
Copy to clipboard
MOORE, DIANA L., VOIGT, JAMES A., WATSON, CHAD S., MCKENZIE, BONNIE B., MOORE, ROGER H., HUTCHINSON, MICHAEL A., LOCKWOOD, STEVEN J., & RODMAN-GONZALES, EMILY D. Chem-Prep PZT 95/5 for Neutron Generator Applications: Powder Fractionation Study of Production-Scale Powders. United States. doi:10.2172/820894.
Copy to clipboard
MOORE, DIANA L., VOIGT, JAMES A., WATSON, CHAD S., MCKENZIE, BONNIE B., MOORE, ROGER H., HUTCHINSON, MICHAEL A., LOCKWOOD, STEVEN J., and RODMAN-GONZALES, EMILY D. Sun . "Chem-Prep PZT 95/5 for Neutron Generator Applications: Powder Fractionation Study of Production-Scale Powders". United States. doi:10.2172/820894. https://www.osti.gov/servlets/purl/820894.
Copy to clipboard
@article{osti_820894,
title = {Chem-Prep PZT 95/5 for Neutron Generator Applications: Powder Fractionation Study of Production-Scale Powders},
author = {MOORE, DIANA L. and VOIGT, JAMES A. and WATSON, CHAD S. and MCKENZIE, BONNIE B. and MOORE, ROGER H. and HUTCHINSON, MICHAEL A. and LOCKWOOD, STEVEN J. and RODMAN-GONZALES, EMILY D.},
abstractNote = {The Materials Chemistry Department 1846 has developed a lab-scale chem-prep process for the synthesis of PNZT 95/5, referred to as the ''SP'' process (Sandia Process). This process (TSP) has been successfully transferred to and scaled-up by Department 14192 (Ceramics and Glass Department), producing the larger quantities of PZT powder required to meet the future supply needs of Sandia for neutron generator production. The particle size distributions of TSP powders routinely have been found to contain a large particle size fraction that was absent in development (SP) powders. This SAND report documents experimental studies focused on characterizing these particles and assessing their potential impact on material performance. To characterize these larger particles, fractionation of several TSP powders was performed. The ''large particle size fractions'' obtained were characterized by particle size analysis, SEM, and ICP analysis and incorporated into compacts and sintered. Large particles were found to be very similar in structure and composition as the bulk of the powder. Studies showed that the large-size fractions of the powders behave similarly to the non-fractionated powder with respect to the types of microstructural features once sintered. Powders were also compared that were prepared using different post-synthesis processing (i.e. differences in precipitate drying). Results showed that these powders contained different amounts and sizes of porous inclusions when sintered. How this affects the functional performance of the PZT 95/5 material is the subject of future investigations.},
doi = {10.2172/820894},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2003},
month = {Sun Jun 01 00:00:00 EDT 2003}
}
Copy to clipboard
Technical Report:
View Technical Report
DOI:  10.2172/820894
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • ; ; ; ...
    The Materials Chemistry Department 1846 has developed a lab-scale chem-prep process for the synthesis of PNZT 95/5, a ferroelectric material that is used in neutron generator power supplies. This process (Sandia Process, or SP) has been successfully transferred to and scaled by Department 14192 (Ceramics and Glass Department), (Transferred Sandia Process, or TSP), to meet the future supply needs of Sandia for its neutron generator production responsibilities. In going from the development-size SP batch (1.6 kg/batch) to the production-scale TSP powder batch size (10 kg/batch), it was important that it be determined if the scaling process caused any ''performance-critical'' changesmore » in the PNZT 95/5 being produced. One area where a difference was found was in the particle size distributions of the calcined PNZT powders. Documented in this SAND report are the results of an experimental study to determine the origin of the differences in the particle size distribution of the SP and TSP powders.« less

  • ; ;
    Chemical synthesis methods are being developed as a future source of PZT 95/5 powder for neutron generator voltage bar applications. Laboratory-scale powder processes were established to produce PZT billets from these powders. The interactions between calcining temperature, sintering temperature, and pore former content were studied to identify the conditions necessary to produce PZT billets of the desired density and grain size. Several binder systems and pressing aids were evaluated for producing uniform sintered billets with low open porosity. The development of these processes supported the powder synthesis efforts and enabled comparisons between different chem-prep routes.

  • ; ; ; ...
    No abstract prepared.

  • ;
    The microstructure and mechanical properties of niobium-modified lead zirconate titanate (PNZT) 95/5 ceramics, where 95/5 refers to the ratio of lead zirconate to lead titanate, were evaluated as a function of lead (Pb) stoichiometry. Chemically-prepared PNZT 95/5 is produced at Sandia National Laboratories by the Ceramics and Glass Processing Department (14154) for use as voltage elements in ferroelectric neutron generator power supplies. PNZT 95/5 was prepared according to the nominal formulation of Pb{sub 0.991+x}(Zr{sub 0.955}Ti{sub 0.045}){sub 0.982}Nb{sub 0.018}O{sub 3+x}, where x (-0.0274 {approx}< x {approx}< 0.0297) refers to the mole fraction of Pb and O that deviated from the stoichiometricmore » value. The Pb concentrations were determined from calcined powders; no adjustments were made to Pb compositions due to weight loss during sintering. The microstructure (second phases, fracture mode and grain size) varied appreciably with Pb stoichiometry, whereas the mechanical properties (hardness, fracture toughness, strength and Weibull parameters) exhibited modest variation. Specimens deficient in Pb, 2.74% (x = -0.0274) and 2.15% (x = -0.02150), had a high area fraction of a zirconia (ZrO{sub 2}) second phase on the order of 0.02. As the Pb content in solid solution increased the ZrO{sub 2} content decreased; no ZrO{sub 2} was observed for the specimen containing 2.97% excess Pb (x = 0.0297). Over the range of Pb stoichiometry most specimens fractured predominately transgranularly; however, 2.97% Pb excess PNZT 95/5 fractured predominately intergranularly. No systematic changes in hardness or Weibull modulus were observed as a function of Pb content. Fracture toughness decreased slightly from 1.8 MPa{center_dot}m{sup 1/2} for Pb deficient specimens to 1.6 MPa{center_dot}m{sup 1/2} for specimens with excess Pb. Although there are microstructural differences with changes in Pb content, the mechanical properties did not vary substantially. However, the average failure stress and fracture toughness for PNZT 95/5 containing 2.97% excess Pb decreased slightly. It is expected that additional increases in Pb content would result in further mechanical property degradation. The decrease in mechanical properties for the 2.97% Pb excess ceramics could be the result of a weaker PbO-rich grain boundary phase present in the material. If better mechanical properties are desired, it is recommended that PNZT 95/5 ceramics are processed by a method whereby any excess Pb is depleted from the final sintered ceramic so that near-stoichiometric values of Pb concentration are reached. Otherwise, a PbO-rich grain boundary phase may exist in the ceramic which could potentially be detrimental to the mechanical properties of PNZT 95/5 ceramics.« less

  • ; ; ; ...
    Niobium doped PZT 95/5 (lead zirconate-lead titanate) is the material used in voltage bars for all ferroelectric neutron generator power supplies. In June of 1999, the transfer and scale-up of the Sandia Process from Department 1846 to Department 14192 was initiated. The laboratory-scale process of 1.6 kg has been successfully scaled to a production batch quantity of 10 kg. This report documents efforts to characterize and optimize the production-scale process utilizing Design of Experiments methodology. Of the 34 factors identified in the powder preparation sub-process, 11 were initially selected for the screening design. Additional experiments and safety analysis subsequently reducedmore » the screening design to six factors. Three of the six factors (Milling Time, Media Size, and Pyrolysis Air Flow) were identified as statistically significant for one or more responses and were further investigated through a full factorial interaction design. Analysis of the interaction design resulted in developing models for Powder Bulk Density, Powder Tap Density, and +20 Mesh Fraction. Subsequent batches validated the models. The initial baseline powder preparation conditions were modified, resulting in improved powder yield by significantly reducing the +20 mesh waste fraction. Response variation analysis indicated additional investigation of the powder preparation sub-process steps was necessary to identify and reduce the sources of variation to further optimize the process.« less