Suspension stability and sintering influence on yttria-stabilized zirconia fabricated by colloidal processing

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Abstract

The stability of nano-zirconia 3YSZ powder in suspension was extensively studied by the colloidal method, and the optimum sintering temperature of the green sample fabricated through slip casting was determined. Zirconia suspensions with 10 vol% powder loading were prepared with distilled water, and HNO3 was used to adjust the pH of the suspension to pH 1-6. All of the suspensions were subjected to sedimentation test, and the results showed that the suspensions adjusted to pH 2 had the lowest sediment volume. This finding indicates that a suspension with pH 2 produces higher packing density. Viscosity test was carried out for the suspensions added with dispersant ranging from 0.3 wt% to 0.7 wt% polyethyleneimine (PEI) with and without pH adjustment. The suspension containing 0.5 wt% PEI with pH 2 adjustment produced the lowest viscosity because of interparticle bond breakage in the aggregates, thus forming colloidally stable suspensions. The zirconia suspension containing 0.5 wt% PEI and whose pH was adjusted to pH 2 was chosen to be slip casted into cylindrical shape. Green samples were sintered at various sintering temperatures that ranged from 1100 C to 1500 C through a two-step sintering method. The sample sintered at 1500 C was found to be porosite-free, and its highest relative density was 99.6% of the theoretical density. Morphological studies detected pores in the microstructure of the samples sintered at low sintering temperatures (1100 and 1200 C). By contrast, the samples sintered at 1400 and 1500 C were fully densified. However, the grain size of the sample sintered at 1500 C was 230 nm, which indicated excessive grain growth. The Vickers hardness of the sample sintered at 1400 C was found to be highest (12.9 GPa) and comparable to results found in the literature.

Original languageEnglish
Pages (from-to)5413-5419
Number of pages7
JournalCeramics International
Volume40
Issue number4
DOIs
Publication statusPublished - May 2014

Fingerprint

Yttria stabilized zirconia
Suspensions
Sintering
Zirconia
Processing
Polyethyleneimine
Viscosity
Powders
Vickers hardness
Grain growth
Sedimentation
Temperature
Sediments
Casting
Microstructure
Water

Keywords

  • A. Slip casting
  • A. Suspension
  • D. ZrO
  • Two-stage sintering

ASJC Scopus subject areas

  • Ceramics and Composites
  • Process Chemistry and Technology
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

@article{3326730f54874ef79077591337c5a04c,
title = "Suspension stability and sintering influence on yttria-stabilized zirconia fabricated by colloidal processing",
abstract = "The stability of nano-zirconia 3YSZ powder in suspension was extensively studied by the colloidal method, and the optimum sintering temperature of the green sample fabricated through slip casting was determined. Zirconia suspensions with 10 vol{\%} powder loading were prepared with distilled water, and HNO3 was used to adjust the pH of the suspension to pH 1-6. All of the suspensions were subjected to sedimentation test, and the results showed that the suspensions adjusted to pH 2 had the lowest sediment volume. This finding indicates that a suspension with pH 2 produces higher packing density. Viscosity test was carried out for the suspensions added with dispersant ranging from 0.3 wt{\%} to 0.7 wt{\%} polyethyleneimine (PEI) with and without pH adjustment. The suspension containing 0.5 wt{\%} PEI with pH 2 adjustment produced the lowest viscosity because of interparticle bond breakage in the aggregates, thus forming colloidally stable suspensions. The zirconia suspension containing 0.5 wt{\%} PEI and whose pH was adjusted to pH 2 was chosen to be slip casted into cylindrical shape. Green samples were sintered at various sintering temperatures that ranged from 1100 C to 1500 C through a two-step sintering method. The sample sintered at 1500 C was found to be porosite-free, and its highest relative density was 99.6{\%} of the theoretical density. Morphological studies detected pores in the microstructure of the samples sintered at low sintering temperatures (1100 and 1200 C). By contrast, the samples sintered at 1400 and 1500 C were fully densified. However, the grain size of the sample sintered at 1500 C was 230 nm, which indicated excessive grain growth. The Vickers hardness of the sample sintered at 1400 C was found to be highest (12.9 GPa) and comparable to results found in the literature.",
keywords = "A. Slip casting, A. Suspension, D. ZrO, Two-stage sintering",
author = "Amat, {Noor Faeizah} and Andanastuti Muchtar and Ghazali, {Mariyam Jameelah} and Norziha Yahaya",
year = "2014",
month = "5",
doi = "10.1016/j.ceramint.2013.10.123",
language = "English",
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pages = "5413--5419",
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T1 - Suspension stability and sintering influence on yttria-stabilized zirconia fabricated by colloidal processing

AU - Amat, Noor Faeizah

AU - Muchtar, Andanastuti

AU - Ghazali, Mariyam Jameelah

AU - Yahaya, Norziha

PY - 2014/5

Y1 - 2014/5

N2 - The stability of nano-zirconia 3YSZ powder in suspension was extensively studied by the colloidal method, and the optimum sintering temperature of the green sample fabricated through slip casting was determined. Zirconia suspensions with 10 vol% powder loading were prepared with distilled water, and HNO3 was used to adjust the pH of the suspension to pH 1-6. All of the suspensions were subjected to sedimentation test, and the results showed that the suspensions adjusted to pH 2 had the lowest sediment volume. This finding indicates that a suspension with pH 2 produces higher packing density. Viscosity test was carried out for the suspensions added with dispersant ranging from 0.3 wt% to 0.7 wt% polyethyleneimine (PEI) with and without pH adjustment. The suspension containing 0.5 wt% PEI with pH 2 adjustment produced the lowest viscosity because of interparticle bond breakage in the aggregates, thus forming colloidally stable suspensions. The zirconia suspension containing 0.5 wt% PEI and whose pH was adjusted to pH 2 was chosen to be slip casted into cylindrical shape. Green samples were sintered at various sintering temperatures that ranged from 1100 C to 1500 C through a two-step sintering method. The sample sintered at 1500 C was found to be porosite-free, and its highest relative density was 99.6% of the theoretical density. Morphological studies detected pores in the microstructure of the samples sintered at low sintering temperatures (1100 and 1200 C). By contrast, the samples sintered at 1400 and 1500 C were fully densified. However, the grain size of the sample sintered at 1500 C was 230 nm, which indicated excessive grain growth. The Vickers hardness of the sample sintered at 1400 C was found to be highest (12.9 GPa) and comparable to results found in the literature.

AB - The stability of nano-zirconia 3YSZ powder in suspension was extensively studied by the colloidal method, and the optimum sintering temperature of the green sample fabricated through slip casting was determined. Zirconia suspensions with 10 vol% powder loading were prepared with distilled water, and HNO3 was used to adjust the pH of the suspension to pH 1-6. All of the suspensions were subjected to sedimentation test, and the results showed that the suspensions adjusted to pH 2 had the lowest sediment volume. This finding indicates that a suspension with pH 2 produces higher packing density. Viscosity test was carried out for the suspensions added with dispersant ranging from 0.3 wt% to 0.7 wt% polyethyleneimine (PEI) with and without pH adjustment. The suspension containing 0.5 wt% PEI with pH 2 adjustment produced the lowest viscosity because of interparticle bond breakage in the aggregates, thus forming colloidally stable suspensions. The zirconia suspension containing 0.5 wt% PEI and whose pH was adjusted to pH 2 was chosen to be slip casted into cylindrical shape. Green samples were sintered at various sintering temperatures that ranged from 1100 C to 1500 C through a two-step sintering method. The sample sintered at 1500 C was found to be porosite-free, and its highest relative density was 99.6% of the theoretical density. Morphological studies detected pores in the microstructure of the samples sintered at low sintering temperatures (1100 and 1200 C). By contrast, the samples sintered at 1400 and 1500 C were fully densified. However, the grain size of the sample sintered at 1500 C was 230 nm, which indicated excessive grain growth. The Vickers hardness of the sample sintered at 1400 C was found to be highest (12.9 GPa) and comparable to results found in the literature.

KW - A. Slip casting

KW - A. Suspension

KW - D. ZrO

KW - Two-stage sintering

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