Doctoral Dissertations

Keywords and Phrases

Calcium Zirconate; Capacitor; Ceramics; HALT; High Temperature; Magnesium Oxide

Abstract

Technical progress in microelectronics is allowing operation in environments that were previously considered impossible. Building complete electronic circuits for applications above 450 degrees C, such as the planned NASA missions to Venus, require a variety of active and passive components, including multilayer ceramic capacitors (MLCC).

This study explores calcium zirconate CaZrO3 and magnesium oxide MgO based dielectric compositions for MLCC applications that are capable of operating at extreme temperatures between 450 degrees C and 600 degrees C. Both materials were characterized with respect to impurities, dopants, crystal structure and microstructural development. Dielectric properties were measured to determine permittivity, dissipation factor, and conductivity as a function of temperature, applied voltage and frequency. The MLCC were tested to failure at various voltage and temperature conditions to determine the mean-time-to-failure (MTTF) using Weibull statistics. Calculations were made to estimate lifespan of capacitors under various conditions, including the maximum allowed voltage to achieve a 10-year lifespan at various temperatures.

MgO showed lower conductivity and longer lifespan at all combinations of temperature and voltage but also exhibited lower dielectric constant. Observations indicated that when operating conditions are more demanding, MgO is a superior dielectric. However, when operating at relatively lower temperatures and voltage conditions where both materials can have acceptable lifespan and conductivity, CaZrO3 is superior due to its higher dielectric constant.

Advisor(s)

Dogan, Fatih

Committee Member(s)

Burn, Ian
Brow, Richard K.
O'Malley, Ronald J.
Huebner, Wayne
Gu, Yijia

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2025

Journal article titles appearing in thesis/dissertation

Paper I, found on pages 42-59, has been published in the International Journal of Applied Ceramic Technology.
Paper II, found on pages 60-78, has been published in the International Journal of Applied Ceramic Technology.
Paper III, found on pages 79-97, has been submitted to the International Journal of Applied Ceramic Technology.

Pagination

xv, 113 pages

Note about bibliography

Includes_bibliographical_references_(pages 109-112)

Rights

© 2025 Alan Daniel Devoe , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12506

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