Pressureless sintering of ceramic composites. Final report

Technical Report · Mon Jan 17 00:00:00 EST 1994

OSTI ID:7275336

Weiser, M W

This project examined the pressureless sintering and densification behavior of model ceramic composites. The effect of inclusion aspect ratio on densification was studied using SiC whiskers and fibers in an Al2O3 matrix. Composites had maximum sintered density when made from fibers with aspect ratios around ten. This peak in the density is a result of the density of short aspect composites being inhibited by inclusion size considerations while long aspect composites are prevented from densifying by percolation related effects. How inhomogeneous inclusion distribution affects densification was studied using SiCP/Al2O3 composites. Three different types of inhomogeneity known as concentration, amplitude, and size were investigated. The sintered density was maximized at moderate levels of inclusion inhomogeneity. The authors also found that various salts were effective coagulating agents for slip casting Al2O3/ZrO2 composites. The drying of composites found that percolation limits the green density of particulate composites. The fracture toughness of Mn-Zn ferrites was increased from 0.9 MPa(square root)m to 2.8 MPa(square root)m by addition of 25 vol% partially stabilized ZrO2. Transient liquid phase sintering of composites is not an effective densification method.

• Research Organization: New Mexico Univ., Albuquerque, NM (United States)
• OSTI ID: 7275336
• Report Number(s): AD-A-277274/7/XAB; CNN: AFOSR-90-0265
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
FABRICATION
SINTERING
COMPOSITE MATERIALS
SILICON CARBIDES
CERAMICS
FIBERS
PROGRESS REPORT
ALUMINIUM COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
DOCUMENT TYPES
MATERIALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
360601* - Other Materials- Preparation & Manufacture