Magnesium oxide enhancement of sintering of alumina

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6138381

Morgan, C. S.; Tennery, V. J.

It is known that small quantites of MgO enhance sintering of Al/sub 2/O/sub 3/, the process of enhancement has not been established. Sintering data for compacts of several oxides heated at various rates to a specific temperaure show that the final density achieved in powder compacts is relatively insensitive to heating rates above about 2/sup 0/C/s. Transmission electron microscopy studies of these compacts show evidence of dislocation generation in the sintering material in regions between adjacent particles. Sintering measurements of compacts of Al/sub 2/O/sub 3/ and MgO doped Al/sub 2/O/sub 3/ show that MgO contributes to the initial densification even when high heating rates are applied to the compacts. Comparison of the observed densification kinetics with those of a diffusion process shows that the experimental results are incompatible with a diffusion controlled process. It is proposed that MgO on the surface of Al/sub 2/O/sub 3/ particles increases the ease of dislocation motion and generation compared to pure Al/sub 2/O/sub 3/. This enhancement improves the compact densification.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: Not Available; USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6138381
• Report Number(s): CONF-790682-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DENSITY
DISLOCATIONS
FABRICATION
HEAT TREATMENTS
LINE DEFECTS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
METALLURGICAL EFFECTS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SINTERING