Effects of the Whisker Orientation and Sintering Temperature on Mechanical Properties of the Si<TEX>$_3$</TEX>N<TEX>$_4$</TEX> based Composites

,; ,; ,; ,

J. Korean Ceram. Soc. > Volume 36(5); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(5): 483.

Whisker의 배열방향과 소결온도가 Si$_3$N$_4$ 복합체의 기계적 성질에 미치는 영향

김창원, 박동수¹

부경대학교 재료공학과
¹한국기계연구원 요업재료그룹

Effects of the Whisker Orientation and Sintering Temperature on Mechanical Properties of the Si$_3$N$_4$ based Composites

ABSTRACT

Gas pressure sintered silicon nitride based composites with 3 wt% $beta$-Si3N4 whiskers were prepared and change of properties according to the whisker orientation and sintering temperature was studied. The tapes with whiskers were fabricated by two different method ; conventional tape casting and a modified tape casting by using guide pins,. Orientations of the whiskers were controlled by different stacking sequences of the sheets cut from the tape. Samples were fully densified by gas pressure sintering at 2148-2273K. As the sintering temperature increased size of the large elongated grains increased. In case of unidirectional samples sintering shrinkage normal to the whisker alignment direction was larger than that of parallel to the direction and the shrinkage anisotropy increased slightly as sintering temperature increased. As sintering temperature increased the crack length parallel to whisker alignment direction became shorter but that normal to the direction did not depend on sintering temperature. In case of cross-plied samples the anisotropy of mechanical properties disappeared.

Key words: Tape casting, whisker orientation, Sintering temperature, Mechanical properties