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Fabrication of Silicon Nitride Nanoceramics and their Tribological Properties
Author(s) -
Kim JaeHee,
Venkata Manoj Kumar B.,
Hong SeongHyeon,
Kim HaiDoo
Publication year - 2010
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.1551-2916.2010.03614.x
Subject(s) - materials science , microstructure , ceramic , carbothermic reaction , grain size , silicon nitride , sintering , spark plasma sintering , grain growth , composite material , phase (matter) , nitride , tribology , metallurgy , layer (electronics) , carbide , chemistry , organic chemistry
Si 2 N 2 O secondary phase‐free, fully dense nano‐Si 3 N 4 ceramics (≥97% of theoretical density) were developed by combining carbothermal reduction treatment and spark plasma sintering (SPS), and their tribological properties were investigated by subjecting to self‐mated sliding under unlubricated conditions. Commercially available Si 3 N 4 nanopowder was used as a starting material and phenolic resin was used for carbothermal reduction, which was conducted at 1450°C for 10 h. Fully densified Si 2 N 2 O phase‐free Si 3 N 4 ceramics with a wide range of grain size from 90 nm to 1.5 μm were fabricated by varying SPS temperature from 1550° to 1750°C. The microstructure of the developed Si 3 N 4 ceramics was changed from nano equi‐axed at 1550°C to large elongated bimodal grain morphology at 1700° or 1750°C. The frictional behavior was not dependent on the microstructure, but the wear rate was strongly influenced such that it decreased by an order of magnitude (from 9.7 × 10 −5 to 0.88 × 10 −5 mm 3 /N·m) with decreasing grain size. The dominant wear mechanism was changed from the delamination of tribochemical layer for the ceramics with nano equi‐axed grain microstructure to the fracture and grain pull‐out for the ceramics with duplex microstructure.