Award Date

May 2016

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics and Astronomy

First Committee Member

Michael Pravica

Second Committee Member

Andrew Cornelius

Third Committee Member

Stephen Lepp

Fourth Committee Member

Paul Forster

Number of Pages

61

Abstract

Yttria Stabilized Zirconia (YSZ) is of interest for many industries. Varying amounts of Yttria (Y2O3) can be doped into Zirconia (ZrO2) to create materials with specific characteristics. For instance, 3mol% YSZ (3YSZ) is known to be a super hard material and is used as a coating on drill tips and as an abrasive. Eight mol% YSZ (8YSZ) is commonly used as a solid electrolyte in Solid Oxide Fuel Cells because of its good ionic conducting abilities and stability at high temperatures. In this thesis project, a novel experimental setup was created and used to study the ionic conductivity of (3 and 8mol%)YSZ with pressure and temperature via in situ impedance spectroscopy measurements inside a diamond anvil cell. Pressures of 0-17GPa and temperatures in the range between 294-523k were achieved during the experiment. Additionally, a powder x- ray diffraction non-hydrostatic high-pressure structural study of the two samples was completed at High Pressure Collaborative Access Team (HP-CAT) Sector 16 at the Advanced Photon Source. It was observed that the ionic conductivity of both sample material decreased with increased pressure. The compression stress caused a decrease in cell volume and the distance between oxygen vacancy sites and mobile oxygen ions became closer. This reduction caused ionic conductivity to decrease.

Keywords

Diamond Anvil Cell; High Pressure; High Temperature; Impedance Spectroscopy; Powder X-ray Diffraction; Yttria Stabilized Zirconia

Disciplines

Condensed Matter Physics | Engineering Science and Materials | Materials Science and Engineering | Physics

Language

English


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