Dopant Effects on Sintering Behavior in Ceramic Matrix Composites [Thesis]

Technical Report · Sat Dec 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/5946199· OSTI ID:5946199

Brown, Gillian L. ^[1]

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1. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering

Heterogeneities present one of the most serious problems in the processing of ceramic bodies. Non-uniformities in a ceramic, such as agglomerates, rigid inclusions, a wide particle size or pore size distribution, or spatial variations in green density can seriously affect sintering behavior, and experiments performed on highly uniform powder compacts have proven the importance of homogeneity within the compact. Powder compacts produced by conventional processing techniques, however, usually contain at least some of the inhomogeneities mentioned above. Particulate ceramic composites are currently being studied a great deal because of their improved fracture toughness and high-temperature creep resistance over single-phase ceramics. The presence of an inert second phase, however, has been found to hinder the densification of the matrix material seriously, even at low volume fractions of the inclusion phase, in a way that is to data not fully understood. Such techniques as hot pressing, hot isostatic pressing, or the incorporation of liquid-phase forming additives must therefore be used to obtain theoretical or near-theoretical densities; however it would be more convenient and more economical to free sinter these composites to full density. It is therefore important to obtain an understanding of the exact effects of heterogeneities on sintering, so that these effects may be countered. In this study, an attempt was made to more fully understand the effects of rigid, non-sinterable inclusions on densification in the ZnO-SiC system.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5946199
• Report Number(s): LBL--30220; ON: DE91009774
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CARBIDES
CARBON COMPOUNDS
CERAMICS
CHALCOGENIDES
COMPOSITE MATERIALS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DILATOMETRY
FABRICATION
MATERIALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
SILICON CARBIDES
SILICON COMPOUNDS
SINTERING
THERMAL ANALYSIS
ZINC COMPOUNDS
ZINC OXIDES