Microstructure and mechanical properties of CaO/MgO-doped Si sub 3 N sub 4 sintered by hot isostatic pressing

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Advanced Ceramic Materials; (USA)

DOI:https://doi.org/10.1111/j.1551-2916.1988.tb00243.x· OSTI ID:5945927

Pejryd, L ^[1]

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1. Seco Tools AB, Fagersta (Sweden)

Using glass-encapsulated hot isostatic pressing, additive-free Si{sub 3}N{sub 4} and Si{sub 3}N{sub 4} containing a 50/50 mol% mixture of CaO and MgO up to 6 wt% were sintered from 1,550{degree} to 1,750{degree}C at 160 MPa. Samples containing oxide additions achieved full density, whereas additive-free samples did not reach full density. In fully densified samples, the Vickers hardness decreased with increasing oxide content and sintering temperature. At 1,000{degree}C the oxide content, and, to a small extent, the sintering temperature, determine hardness. Fracture toughness increases with increasing oxide content and increasing sintering temperature. However, transformation of {alpha}-Si{sub 3}N{sub 4} to {beta}-Si{sub 3}N{sub 4} is enhanced by the temperature, but the oxide content has no significant effect.

• OSTI ID: 5945927
• Journal Information: Advanced Ceramic Materials; (USA), Journal Name: Advanced Ceramic Materials; (USA) Vol. 3:4; ISSN 0883-5551; ISSN ACEME
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL STRUCTURE
DATA
DIFFRACTION
DOPED MATERIALS
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
FABRICATION
FRACTURE PROPERTIES
HOT PRESSING
INFORMATION
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
MATERIALS WORKING
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
PRESSING
SCANNING ELECTRON MICROSCOPY
SCATTERING
SILICON COMPOUNDS
SILICON NITRIDES
X-RAY DIFFRACTION