Grain size and temperature dependence of the threshold stress for superplastic deformation in yttria-stabilized zirconia polycrystals

1998 ◽  
Vol 247 (1-2) ◽  
pp. 97-101 ◽  
Author(s):  
A Domı́nguez-Rodrı́guez ◽  
A Bravo-León ◽  
J.D Ye ◽  
M Jiménez-Melendo
Keyword(s):  
Grain Size ◽  
Temperature Dependence ◽  
Superplastic Deformation ◽  
Threshold Stress ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia

The role of a threshold stress in the superplastic deformation of fine-grained yttria-stabilized zirconia polycrystals

1996 ◽  
Vol 34 (7) ◽  
pp. 1155-1160 ◽  
Author(s):  
Alfonso Bravo-León ◽  
Manuel Jiménez-Melendo ◽  
Arturo Domínguez-Rodríguez ◽  
Atul H. Chokshi
Keyword(s):  
Superplastic Deformation ◽  
Threshold Stress ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Fine Grained

A Comparative Study of Superplastic Deformation and Cavitation Failure in a Yttria Stabilized Zirconia and a Zirconia Alumina Composite

1990 ◽  
Vol 196 ◽  
Author(s):  
A. H. Chokshi ◽  
D. J. Schissler ◽  
T.-G. Nieh ◽  
J. Wadsworth
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Superplastic Deformation ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Experimental Conditions ◽  
Fine Grained ◽  
Grain Sizes ◽  
Alumina Composite ◽  
Cavitation Failure

ABSTRACTA fine grained yttria stabilized zirconia and a zirconia composite containing 20% alumina exhibit superplastic characteristics, with optimum elongations to failure of ≥500%. There is microstructural evidence for deformation enhanced grain growth and concurrent cavitation in both of these superplastic ceramics. Grain sizes after superplastic deformation may be several times larger than the initial grain size, and the level of cavitation can attain values as high as ≥30% under some experimental conditions. This report presents in a comparative format some recent experimental results on the microstructural aspects of superplastic deformation and concurrent cavitation in these superplastic ceramics.

Elaboration of Sol-Gel Derived Hydroxyapatite / Yttria Stabilized Zirconia Composite Coatings Obtained for Biomedical Application

2011 ◽  
Vol 312-315 ◽  
pp. 894-899
Author(s):  
Sahar Salehi ◽  
Mohammad Hosseien Fathi
Keyword(s):  
Grain Size ◽  
Crystallite Size ◽  
Grain Growth ◽  
Biomedical Application ◽  
Composite Coatings ◽  
Sol Gel ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Nanostructured Composite

In this study, nanostructured composite coatings of hydroxyapatite (HA)/ 30wt% yttria stabilized zirconia (YSZ) coatings containing 0, 3, 5, and 8 mol% Y2O3 (namely; HA-0YSZ, HA-3YSZ, HA-5YSZ, and HA-8YSZ) were successfully synthesized using the sol-gel method. The crystallite size of the coating was about ~44-58 nm for tetragonal and cubic zirconia grain size and 75-87 nm for hydroxyapatite grain size. Crack-free and homogeneous HA-YSZ composite coatings were obtained with no observable defects. The uniform distribution of zirconia particles in a composite would be highly beneficial for obtaining homogeneous coatings of HA-YSZ film and would hinder grain growth of HA phase during calcinations. In vitro evaluation in 0.9% NaCl showed that Ca2+ dissolution rate of composite coatings was lower than pure HA coatings.

scholarly journals Grain Boundary Resistivity of Yttria-Stabilized Zirconia at 1400°C

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
J. Wang ◽  
A. Du ◽  
Di Yang ◽  
R. Raj ◽  
H. Conrad
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Electric Field ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Brick Layer Model ◽  
Dc Electric Field ◽  
Lower Temperature ◽  
Boundary Width ◽  
Grain Boundary Resistivity

The grain size dependence of the bulk resistivity of 3 mol% yttria-stabilized zirconia at 1400°C was determined from the effect of a dc electric field Ea=18.1 V/cm on grain growth and the corresponding electric current during isothermal annealing tests. Employing the brick layer model, the present annealing test results were in accordance with extrapolations of the values obtained at lower temperature employing impedance spectroscopy and 4-point-probe dc. The combined values give that the magnitude of the grain boundary resistivity ρb=133 ohm-cm. The electric field across the grain boundary width was 28–43 times the applied field for the grain size and current ranges in the present annealing test.

Effect of Precursor Grain Size on the Sinterability and Conductivity of Commercial Yttria-Stabilized Zirconia as Solid Electrolyte

2018 ◽  
Vol 775 ◽  
pp. 331-335
Author(s):  
Anna Romina T. Mercado ◽  
Emmalin S. Mesina ◽  
Jennet R. Rabo ◽  
Rinlee Butch M. Cervera
Keyword(s):  
Grain Size ◽  
Chemical Properties ◽  
Fluorite Structure ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Electrolysis Cell ◽  
Total Conductivity ◽  
Stabilized Zirconia ◽  
Sem Images ◽  
Solid Oxide Electrolysis Cell

Solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) have been receiving significant attention for future energy storage and hydrogen production applications. This research focuses on the electrolyte material which can be used for both SOEC and SOFC particularly on 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte material. YSZ has been used because of its high stability at elevated temperature, excellent mechanical and chemical properties and its excellent oxygen ion conductivity. This study aims to determine the effect of precursor’s grain size and sintering temperature on the properties of YSZ as electrolyte material for SOEC. Solid-state sintering was done to transform the ceramic powders into solid compacts. Pure cubic fluorite structure YSZ was achieved by both micrograined and nanograined YSZ sintered at 1200°C and 1500°C. It was observed that the micrograined YSZ sample sintered at 1500°C achieved the highest relative density at 99.48%. SEM images showed a smooth and compact microstructure for micrograined YSZ while small pores were still present in the micrographs of nanograined YSZ. However, interestingly, the nanograined YSZ has higher total conductivity as compared to the micrograined YSZ.

Effect of Alumina Additions on Mechanical and Electrical Properties of 8mol% Yttria-Stabilized Zirconia Prepared by Spark Plasma Sintering

2006 ◽  
Vol 317-318 ◽  
pp. 917-920
Author(s):  
Jae Kwang Kim ◽  
Kyung Hun Kim ◽  
Yong Ho Choa ◽  
Jong Won Yoon ◽  
Kwang Bo Shim
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Average Particle Size ◽  
Yttria Stabilized Zirconia ◽  
Average Particle ◽  
Stabilized Zirconia ◽  
Plasma Sintering ◽  
Spark Plasma

Dense 8mol% yttria-stabilized zirconia (8YSZ) consisting of submicrometer-sized grains was prepared using spark plasma sintering (SPS) along with Al2O3 additives. The starting powder with average particle size of 50nm was densified to 98% of the relative density with short sintering time (5min) at 1200 while preserving a submicrometer grain size. The fracture toughness and bending strength showed maximum values of 2.54MPam1/2 and 380MPa at 2vol% alumina-added 8YSZ, due mainly to the higher relative density and small grain size. The electrical conductivity of 2vol% alumina-added 8YSZ was 0.0278 S/cm at 700 in airThus, alumina additions in 8YSZ using the SPS method are an effective process to improve the mechanical strength and electrical conductivity.

Chemically Derived Yttria-Stabilized Zirconia for Plasma-Spraying

1990 ◽  
Vol 180 ◽  
Author(s):  
Fawzy G. Sherif ◽  
H. Herman
Keyword(s):  
Grain Size ◽  
Tetragonal Zirconia ◽  
Yttria Stabilized Zirconia ◽  
Metal Alkoxides ◽  
Stabilized Zirconia ◽  
Spray Coatings ◽  
Plasma Spray Coatings ◽  
Hydrolysis Conditions ◽  
Controlled Hydrolysis ◽  
Zirconia Powders

ABSTRACTYttria-stabilized zirconia powders were prepared by three chemical routes utilizing emulsion hydrolysis techniques. Metal alkoxides, acetates and mixtures of alkoxides and acetates were used as starting materials. Under controlled hydrolysis conditions, particles with different morphology and size were obtained. Spherical or granular particles in the range of 20–60u in diameter were formed. The grain size varied from 0.1–0.2u. The powders were applied successfully as plasma spray coatings. The chemical uniformity was demonstrated by the presence of 100% non-transformable tetragonal zirconia in the powder and in the coating.

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