Phase evolution during spark plasma sintering of novel Si3N4-doped TiB2–SiC composite

Journal Article · Thu Nov 15 04:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.08.043· OSTI ID:22805850

Dashti Germi, Mohammad; Hamidzadeh Mahaseni, Zahra; Ahmadi, Zohre

Highlights: • The effect of Si{sub 3}N{sub 4} addition on microstructure of TiB{sub 2}–SiC composite was studied. • Fully dense TiB{sub 2}-based composite was obtained by addition of SiC and Si{sub 3}N{sub 4}. • TiC, B{sub 4}C and SiO{sub 2} were formed in Si{sub 3}N{sub 4}-free and Si{sub 3}N{sub 4}-doped TiB{sub 2}–SiC ceramics. • TiN and BN were in-situ formed only in Si{sub 3}N{sub 4}-doped TiB{sub 2}–SiC sample. - Abstract: Spark plasma sintering process was employed to fabricate TiB{sub 2}–SiC and novel Si{sub 3}N{sub 4}-doped TiB{sub 2}–SiC ceramic composites at 1900 °C for 7 min under 40 MPa. The microstructural development of TiB{sub 2}-based composites was significantly influenced by the addition of SiC as a reinforcement phase and Si{sub 3}N{sub 4} as a sintering aid. Thermodynamic assessment, X-ray diffractometry, scanning electron microscopy and energy dispersive spectroscopy disclosed the in-situ formation of TiC, B{sub 4}C and SiO{sub 2} in both samples as well as TiN and BN in the Si{sub 3}N{sub 4}-doped TiB{sub 2}–SiC sample through the chemical reactions of SiC and Si{sub 3}N{sub 4} additives with the surface oxide impurities of TiB{sub 2} particles (TiO{sub 2} and B{sub 2}O{sub 3}). The elimination of harmful oxide layers and the in-situ formation various secondary phases had remarkable influences on the sinterability and final microstructure of TiB{sub 2}.

• OSTI ID: 22805850
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 145; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON CARBIDES
BORON NITRIDES
BORON OXIDES
DOPED MATERIALS
LAYERS
MICROSTRUCTURE
PRESSURE RANGE MEGA PA 10-100
SCANNING ELECTRON MICROSCOPY
SILICON CARBIDES
SILICON NITRIDES
SILICON OXIDES
SINTERING
SURFACES
THERMODYNAMICS
TITANIUM BORIDES
TITANIUM CARBIDES
TITANIUM NITRIDES
TITANIUM OXIDES
X-RAY DIFFRACTION