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Dielectric properties of alumina/zirconia composites at millimeter wavelengths; Propiedades dielectricas de compuestos de alumina/zircona a frequencias milimetricas

Technical Report:

Abstract

Alumina-zirconia composites with ZrO{sub 2} contents up to 20% and negligible porosity were investigated at millimeter (mm) wavelengths to determine the changes appearing in the dielectric properties of pure alumina ceramics when unstabilized or partially stabilized ZrO{sub 2} is added to improve the mechanical strength. It is demonstrated that it essential to distinguish between the contributions of the monoclinic and the tetragonal phase of zirconia (m-ZrO{sub 2}, t-ZrO{sub 2}). Permittivity is raised with increasing content of either phases; the effective permittivity can be assessed by the rule of mixtures (Maxwell-Garnett formulation of the generalized Clasussius-Mossotti relation) using permittivity values of 10 for Al{sub 2}O{sub 3}, 14-21 for m-ZrO{sub 2} and 40-45 for t-ZrO{sub 2}. The permittivity data show only a small variation in the investigated range of 9-145 GHz. For the dielectric loss, there is evidence of a predominant contribution of m-ZrO{sub 2}; in addition, the marked increase in loss with frequency becomes sharper. The t-ZrO{sub 2}, which is responsible for strengthening, does not show any significant influence on losses. It is therefore concluded, that ZrO{sub 2} strengthening of alumina is feasible without affecting mm-wave losses at room temperature as long as the presence of m-ZrO{sub 2} is avoided.
Publication Date:
Dec 01, 1994
Product Type:
Technical Report
Report Number:
CIEMAT-736
Reference Number:
SCA: 360204; PA: SPN-94:0B0787; EDB-95:015598; SN: 94001295722
Resource Relation:
Other Information: PBD: [1994]
Subject:
36 MATERIALS SCIENCE; DIELECTRIC PROPERTIES; ALUMINIUM OXIDES; PERMITTIVITY; DIELECTRIC MATERIALS; CORUNDUM; CAVITY RESONATORS; 360204; PHYSICAL PROPERTIES
OSTI ID:
10104701
Research Organizations:
Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain)
Country of Origin:
Spain
Language:
English
Other Identifying Numbers:
Other: ON: DE95721645; TRN: ES94B0787
Availability:
OSTI; NTIS; INIS
Submitting Site:
INIS
Size:
16 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Molla, J, Heidinger, R, Ibarra, A, and Link, G. Dielectric properties of alumina/zirconia composites at millimeter wavelengths; Propiedades dielectricas de compuestos de alumina/zircona a frequencias milimetricas. Spain: N. p., 1994. Web.
Molla, J, Heidinger, R, Ibarra, A, & Link, G. Dielectric properties of alumina/zirconia composites at millimeter wavelengths; Propiedades dielectricas de compuestos de alumina/zircona a frequencias milimetricas. Spain.
Molla, J, Heidinger, R, Ibarra, A, and Link, G. 1994. "Dielectric properties of alumina/zirconia composites at millimeter wavelengths; Propiedades dielectricas de compuestos de alumina/zircona a frequencias milimetricas." Spain.
@misc{etde_10104701,
title = {Dielectric properties of alumina/zirconia composites at millimeter wavelengths; Propiedades dielectricas de compuestos de alumina/zircona a frequencias milimetricas}
author = {Molla, J, Heidinger, R, Ibarra, A, and Link, G}
abstractNote = {Alumina-zirconia composites with ZrO{sub 2} contents up to 20% and negligible porosity were investigated at millimeter (mm) wavelengths to determine the changes appearing in the dielectric properties of pure alumina ceramics when unstabilized or partially stabilized ZrO{sub 2} is added to improve the mechanical strength. It is demonstrated that it essential to distinguish between the contributions of the monoclinic and the tetragonal phase of zirconia (m-ZrO{sub 2}, t-ZrO{sub 2}). Permittivity is raised with increasing content of either phases; the effective permittivity can be assessed by the rule of mixtures (Maxwell-Garnett formulation of the generalized Clasussius-Mossotti relation) using permittivity values of 10 for Al{sub 2}O{sub 3}, 14-21 for m-ZrO{sub 2} and 40-45 for t-ZrO{sub 2}. The permittivity data show only a small variation in the investigated range of 9-145 GHz. For the dielectric loss, there is evidence of a predominant contribution of m-ZrO{sub 2}; in addition, the marked increase in loss with frequency becomes sharper. The t-ZrO{sub 2}, which is responsible for strengthening, does not show any significant influence on losses. It is therefore concluded, that ZrO{sub 2} strengthening of alumina is feasible without affecting mm-wave losses at room temperature as long as the presence of m-ZrO{sub 2} is avoided.}
place = {Spain}
year = {1994}
month = {Dec}
}