Das, Probal Kumar and Mukerji, Joydeb (1988) Sintering behavior and properties of Si3N4 sintered with nitrogen-rich liquid in the system Y2O3-AlN-SiO2. Advanced Ceramic Materials, 3 (3). pp. 238-243. ISSN 0883-5551

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Abstract

Pressureless sintering of Si3N4 with selected liquid compositions from the system Y2O3-AlN-SiO2 has been reported. Compositions were selected so that the grain-boundary liquid produced YAG(3Y2O3.5Al2O3) after crystallization. Studies on dynamic sintering indicated that the first liquid formation occurred between 1278 and 1305C and the maximum sintering rate was observed between 1590 and 1610C depending on the compositions. Si2N2O, YAG, or YAG along with YSiO2N were the crystalline phases obtained on devitrification as the composition moved toward the AlN corner. The grain-boundary liquid phase could be reduced from 20 to 9% on crystallization. Highest flexural strength and fracture toughness obtained were 475 MPa (four-point, 45 to 20mm span) and 6. 8 MPa.square root m, respectively. The effect of crystallization on high-temperature strength and toughness was beneficial in all cases. The creep rate of the sintered product varied from 10.0 x10 to the -7 power to 0.00004/h between 1200 and 1450 C and at 200 to 350 MPa stresses.

Item Type:	Article
Subjects:	Engineering Materials
Divisions:	UNSPECIFIED
Depositing User:	Namita Dutta
Date Deposited:	08 Nov 2013 07:15
Last Modified:	08 Nov 2013 07:15
URI:	http://cgcri.csircentral.net/id/eprint/2196

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