Effect of microstructure on the wear resistance of silicon nitride. [Effects of compositions of Al sub 2 O sub 3 and Y sub 2 O sub 3 additives]

Thesis/Dissertation · Tue Dec 31 23:00:00 EST 1991

OSTI ID:7203984

Zutshi, A

Commercial silicon nitride powder was hot pressed in the presence of additives (5 wt% Al{sub 2}O{sub 3}, 2 wt% Y{sub 2}O{sub 3}) to complete density. The resulting microstructure showed elongated {beta}-Si{sub 3}N{sub 4} grains with no trace of any remaining {alpha}-Si{sub 3}N{sub 4}. The microstructure of the samples was altered by changing the hot pressing schedules. Mechanical properties such as Young's modulus, hardness, fracture strength and fracture toughness were measured for samples with different microstructures. Wear tests were conducted on a reciprocating pin-on-disc apparatus with paraffin oil as a lubricant. The wear on the silicon nitride pin increased as the hardness of the samples decreased. Further, the low hardness samples showed a considerable amount of fracture on the surface. Modification of the composition to 5 wt% Y{sub 2}O{sub 3}, 2 wt% Al{sub 2}O{sub 3} and 5 wt% Al{sub 2}O{sub 3}, 5 wt% Y{sub 2}O{sub 3} changed the mechanical properties of the samples. However, the wear behavior was similar to that of the samples tested originally i.e., as hardness decreased, wear of the pin increased, providing additional evidence for the proposed wear mechanism by plastic deformation.

• Research Organization: Rutgers--the State Univ., New Brunswick, NJ (United States)
• OSTI ID: 7203984
• 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
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL STRUCTURE
FABRICATION
HOT PRESSING
MATERIALS WORKING
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
PRESSING
SILICON COMPOUNDS
SILICON NITRIDES
TRANSITION ELEMENT COMPOUNDS
WEAR RESISTANCE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES