Isolated Pore Generation Mechanism and Mechanical Properties in MAS System with 3Y-TZP

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J. Korean Ceram. Soc. > Volume 30(11); 1993 > Article

Journal of the Korean Ceramic Society 1993;30(11): 881.

MAS계에서 3Y-TZP 첨가에 따른 독립 기공 생성기구와 기계적 성질

최성철, 박현철

한양대학교 공과대학 무기재료공학과

Isolated Pore Generation Mechanism and Mechanical Properties in MAS System with 3Y-TZP

ABSTRACT

MAS system has narrow sintering temp. range due to the liquid phae sintering and thereby densify rapidly. And especially, its poor mechanical properties limitedthe industrial application. In this study, the improvement of mechanical properties and densification is suggested by the consideration of the toughening mechanisms and isolated pore generation mechanism which is derived by the liquid phase sintering theory in 3Y-TZP added composites. After Pressureless sintering up to 140$0^{circ}C$ for 5hr, the dihedral angle and contact angle are analyzed by the observation of microstructure. As a result of microstructure analysis, the sintering stage of the specimen sintered for 5hr is analyzed as solid-skeleton stage. And the isolated pore generation mechanisms are considered as (1) The swelling of the liquid phase is predominent due to the facts that dihedral angle is larger than 60$^{circ}$, contact angle is large and that liquid volume fraction is smaller than 10%. (2) The porous characteristics of the MAS system is also suggested as: the SiO2-rich liquid film is firstly formed at the srface and therefore this reduces the contiguity of the pore, which induces the isolated pore. The strength and fracture toughness increased with the addition of 3Y-TZP and the main fracture toughness improvement mechanisms are analyzed as the crack deflection.