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Tribological Properties of Unidirectionally Aligned Silicon Nitride
Author(s) -
Nakamura Masateru,
Hirao Kiyoshi,
Yamauchi Yukihiko,
Kanzaki Shuzo
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb01057.x
Subject(s) - materials science , silicon nitride , microstructure , tribology , composite material , ceramic , plane (geometry) , perpendicular , grain size , sintering , nitride , anisotropy , silicon , lubricant , metallurgy , geometry , optics , layer (electronics) , mathematics , physics
A silicon nitride ceramic with unidirectionally aligned β‐Si 3 N 4 elongated grains (UA‐SN) was fabricated by sintering the extruded Si 3 N 4 green body with a small amount of rodlike β‐Si 3 N 4 seed. The effect of anisotropy in microstructure on tribological properties was investigated, compared with a fine‐grained Si 3 N 4 without seed. Block‐on‐ring tests without lubricant were conducted at sliding speeds of 0.15 and 1.5 m/s, with a normal load of 5 N and a sliding distance of 75 m, using the UA‐SN and Si 3 N 4 without seeds as block specimens and commercially supplied Si 3 N 4 as ring specimens. For UA‐SN, tribological properties were evaluated in three directions with respect to the grain alignment: the plane normal to the grain alignment, and in the direction parallel to or perpendicular to the grain alignment in the side plane. For both sliding speeds, the plane normal to the grain alignment exhibited the highest wear resistance, and the worn surface of this plane was quite smooth, in contrast to the other specimens whose surfaces were irregular owing to grain dropping. It is considered that the high wear resistance achieved in this plane is attributable to the inhibition of crack propagation along the sliding surface by the stacked elongated grains normal to the sliding surface.