Effects of sintering on grain growth and density in trivalent cation doped zirconia

Yttria stabilized zirconia has been widely used in applications due to its good thermal stability and ionic conductivity. Especially, in order to have better ionic conductivity, a dense microstructure with large grain size is desirable given the typically negative effect of grain boundaries on ionic conductivity. In this work, doped zirconia samples with various dopant concentration (15mol% YO1.5, 30mol% YO1.5, 30mol% YbO1.5 and 30mol% GdO1.5) are studied. The powders were made by using the reverse co-precipitation method. Two-step sintering was used to make dense samples with large grain size and investigated how this sintering method affects grain size and density. The first sintering step was spark plasma sintering (SPS) and the second sintering step was pressureless conventional sintering (CS). The grain growth that occurred during both sintering steps was different depending on the concentration of dopant and the type of dopant due to the different surface energy and cation diffusivity. The density unexpectedly decreased between the first sintering step (SPS) and the second sintering step (CS). It is tentatively attributed to the influence of high heating rate of SPS and high sintering temperature of conventional sintering.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Oh, Hyunkyung

Contributors dc:contributor

• Krogstad, Jessica A

• Sintering
• Ysz
• Microstructures

Statement dc:rights

• Copyright 2023 Hyunkyung Oh

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/121452

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F121452