Compaction of submicron and nanocrystalline Al{sub 2}O{sub 3}-ZrO{sub 2} ceramics

Conference · Tue Sep 01 04:00:00 EDT 1992

OSTI ID:10179859

McKittrick, J; Tunaboylu, B ^[1]; Katz, J ^[2]

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1. California Univ., San Diego, La Jolla, CA (United States)
2. Los Alamos National Lab., NM (United States)

The eutectic in the Al{sub 2}O{sub 3}-ZrO{sub 2} system was rapidly solidified by heating with an 0{sub 2}-H{sub 2} torch and then quenching the melt with a twin roller device. The as-quenched material, which was amorphous or nanocrystalline, was milled with B{sub 4}C or Al{sub 2}0{sub 3} media and pressed into pellets which were sintered conventionally or with microwaves. Samples contaminated with boron carbideresulted in compacts with substantially reduced porosity and a lower fraction of tetragonal ZrO{sub 2}. Conventional sintering at low temperatures resulted in the formation of ``rods`` of an Al{sub 2}0{sub 3} rich phase which grew from the presence of a low melting B{sub 2}0{sub 3}-rich liquid. Conventional and microwave sintering at temperatures up to 1600{degrees}C resulted in a microstructure where 100--200 nm ZrO{sub 2} grains were present intragranularly in the {alpha}-Al{sub 2}0{sub 3} grains. Larger ZrO{sub 2} grains ({approximately}1 {mu}m) were found intergranularly. As-quenched lamellar microstructures were preserved at low temperatures but spheroidized at sintering temperatures > 1600{degrees}C.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: Department of Defense, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10179859
• Report Number(s): LA-UR--92-2721; CONF-9207146--1; ON: DE92040233
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201
ALUMINIUM OXIDES
BINARY MIXTURES
BORON CARBIDES
BORON OXIDES
COMPACTING
EUTECTICS
MICROSTRUCTURE
POWDERS
PREPARATION AND FABRICATION
SCANNING ELECTRON MICROSCOPY
SINTERING
X-RAY DIFFRACTION
ZIRCONIUM OXIDES