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Title: High pressure FAST of nanocrystalline barium titanate

Here, this work studies the microstructural evolution of nanocrystalline (<1 µm) barium titanate (BaTiO 3), and presents high pressure in field-assisted sintering (FAST) as a robust methodology to obtain >100 nm BaTiO 3 compacts. Using FAST, two commercial ~50 nm powders were consolidated into compacts of varying densities and grain sizes. Microstructural inhomogeneities were investigated for each case, and an interpretation is developed using a modified Monte Carlo Potts (MCP) simulation. Two recurrent microstructural inhomogeneities are highlighted, heterogeneous grain growth and low-density regions, both ubiqutously present in all samples to varying degrees. In the worst cases, HGG presents an area coverage of 52%. Because HGG is sporadic but homogenous throughout a sample, the catalyst (e.g., the local segregation of species) must be, correspondingly, distributed in a homogenous manner. MCP demonstrates that in such a case, a large distance between nucleating abnormal grains is required—otherwise abnormal grains prematurely impinge on each other, and their size is not distinguishable from that of normal grains. Compacts sintered with a pressure of 300 MPa and temperatures of 900 °C, were 99.5% dense and had a grain size of 90±24 nm. These are unprecedented results for commercial BaTiO 3 powders or any starting powder ofmore » 50 nm particle size—other authors have used 16 nm lab-produced powder to obtain similar results.« less
 [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of California, Davis, CA (United States)
  2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  3. Univ. of California, Irvine, CA (United States)
  4. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0272-8842; PII: S0272884216308136
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Ceramics International
Additional Journal Information:
Journal Volume: 42; Journal Issue: 12; Journal ID: ISSN 0272-8842
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; barium titanate; sintering; grain size; Spark plasma sintering
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1325373