Skip to main content
×
Home
    • Aa
    • Aa

Colloidal processing of chemically prepared zinc oxide varistors. Part I: Milling and dispersion of powder

  • Nelson S. Bell (a1), Joe Cesarano (a1), James A. Voigt (a1), Steve J. Lockwood (a1) and Duane B. Dimos (a1)...
Abstract

Chemically prepared zinc oxide powders are fabricated for the production of high aspect ratio varistor components. Colloidal processing was performed to reduce agglomerates to primary particles, form a high solids loading slurry, and prevent dopant migration. The milled and dispersed powder exhibited a viscoelastic to elastic behavioral transition at a volume loading of 43–46%. The origin of this transition was studied using acoustic spectroscopy, zeta potential measurements, and oscillatory rheology. The phenomenon occurs due to a volume fraction solids dependent reduction in the zeta potential of the solid phase. It is postulated to result from divalent ion binding within the polyelectrolyte dispersant chain and was mitigated using a polyethylene glycol plasticizing additive. This allowed for increased solids loading in the slurry and a green body fabrication study to be presented in our companion paper.

Copyright
Corresponding author
a) Address all correspondence to this author. e-mail: nsbell@sandia.gov
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

1W.M. Sigmund , N.S. Bell and L. Bergstrom , Novel powder processing methods for advanced ceramics. J. Am. Ceram. Soc. 83, 1557 (2000).

2A. Vojta and D.R. Clarke , Electrical-impulse-induced fracture of zinc oxide varistor ceramics. J. Am. Ceram. Soc. 80, 2086 (1997).

7L. Bergstrom , K. Shinosaki , H. Tomiyama and N. Mitzutani , Colloidal processing of a very fine BaTiO3 powder—effect of particle interactions on the suspension properties, consolidation, and sintering behavior. J. Am. Ceram. Soc. 80, 291 (1997).

8L. Bergstrom , Rheological properties of concentrated, nonaqueous silicon nitride suspensions. J. Am. Ceram. Soc. 79, 3033 (1996).

9J. Cesarano , I.A. Aksay and A. Bleier , Stability of aqueous alpha-alumina suspensions stabilized with polyelectrolytes. J. Am. Ceram. Soc. 71, 250 (1988).

12S.B. Johnson , A.S. Russell and P.J. Scales , Volume fraction effects in shear rheology and electroacoustic studies of concentrated alumina and kaolin suspensions. Colloids Surf. A 141, 119 (1998).

13A.S. Dukhin and P.J. Goetz , Acoustic and electroacoustic spectroscopy for characterizing concentrated dispersions and emulsions. Adv. Colloid Interface Sci. 92, 73 (2001).

14A.S. Dukhin and P.J. Goetz , New developments in acoustic and electroacoustic spectroscopy for characterizing concentrated dispersions. Colloids Surf. A 192, 267 (2001).

16R.D. Porasso , J.C. Benegas and M.A.G.T. van den Hoop , Chemical and electrostatic association of various metal ions by poly(acrylic acid) and poly(methacrylic acid) as studied by potentiometry. J. Phys. Chem. B 103, 2361 (1999).

17J. Sun , L. Bergstrom and L. Gao , Effect of magnesium ions on the adsorption of poly(acrylic acid) onto alumina. J. Am. Ceram. Soc. 84, 2710 (2001).

18T. Abraham , A. Kumpulainen , Z. Xu , M. Rutland , P.M. Claesson and J. Masliyah , Polyelectrolyte-mediated interaction between similarly charged surfaces: Role of divalent counter ions in tuning surface forces. Langmuir 17, 8321 (2001).

19M. Zeghal and L. Auvray , Structure of polymer complexes in water. Europhys. Lett. 45, 482 (1999).

20K. Podhajecka , M. Stepanek , K. Prochazka and W. Brown , Hybrid polymeric micelles with hydrophobic cores and mixed polyelectrolyte/nonelectrolyte shells in aqueous media. 2. Studies of the shell behavior. Langmuir 17, 4245 (2001).

22R.R. Netz , Charge regulation of weak polyelectrolytes at the low- and high-dielectric constant substrates. J. Phys. Condens. Matter 15 S239 (2003).

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Materials Research
  • ISSN: 0884-2914
  • EISSN: 2044-5326
  • URL: /core/journals/journal-of-materials-research
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords: