Maiti, Subrata Kumar and Sarkar, Soumya and Wani, Md Farooq and Das, Probal Kumar (2015) Mechanical and Tribological Performance of Graphite/Silicon Nitride Composites: A Comparison between Pressureless and Spark Plasma Sinter Processing. Metallurgical and Materials Transactions A-Physical Metallurg and Materials Science, 46A (12). pp. 5719-5726. ISSN 1073-5623

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Abstract

Graphite particle (GP)-reinforced silicon nitride (Si3N4) composites were fabricated using pressureless sintering (PLS) and spark plasma sintering (SPS) in the presence of Y2O3-AlN-SiO2 ternary system. Different densification behaviors of the specimens fabricated by PLS and SPS were observed. While increasing GP content drastically reduced matrix densification during PLS at 2023 K (1750 degrees C) with 2 hours dwell, SPS at 1923 K (1650 degrees C) for only 10 minute under 50 MPa pressure resulted in much dense composites even up to 3.5 wt pct GP loading. Mechanical and tribological characterizations revealed that SPS-ed composites can offer improved performance compared to pure Si3N4. SPS-ed 1.5 wt pct GP/Si3N4 composite offered the highest resistance to wear up to 20 N normal load. Wear rate (W-R) of that composite reduced by similar to 24 pct than that obtained for pure Si3N4 (W-R approximate to 1.14 x 10(-3) mm(3)/N m). Furthermore, WR of SPS-ed 2.5 wt pct GP/Si3N4 composite at F-N = 10 to 20 N was found to be only -1/8th of WR values of PLS-ed 2.5 wt pct GP/Si3N4 composite (W-10N(R) approximate to 6.61 x 10(-3) mm(3)/Nm; W-20N(R) approximate to 9.45 x 10(-3) mm(3)/Nm). Present study indicated promising opportunity of SPS for fabricating improved Si3N4 composites through GP addition. The reinforcing particles not only rendered its self-lubrication effect to SPS consolidated composites but also significantly promoted the rate of matrix densification during SPS cycle by the virtue of its high thermal and electrical conducting nature. (C) The Minerals, Metals & Materials Society and ASM International 2015

Item Type:	Article
Subjects:	Engineering Materials
Divisions:	Non-Oxide Ceramics & Composites
Depositing User:	Bidhan Chaudhuri
Date Deposited:	28 Jan 2016 09:30
Last Modified:	26 May 2016 04:40
URI:	http://cgcri.csircentral.net/id/eprint/3138

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