A Study on Zirconia/Metal Functionally Gradient Materials by Sintering Method (III)

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J. Korean Ceram. Soc. > Volume 32(12); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(12): 1337.

소결법에 의한 $ZrO_2/Metal$계 경사기능재료에 관한 연구(III)

정연길, 최성철, 박철원¹

한양대학교 공과대학 무기재료공학과
¹한양여자전문대학 도자기공예과

A Study on Zirconia/Metal Functionally Gradient Materials by Sintering Method (III)

ABSTRACT

TZP/SUS- and ZT/SUS-functionally gradient materials (FGM) were fabricated by pressureless sintering in Ar-atmosphere. The sintering defects such as warping, frustrum formation, splitting and cracking which originated from shrinkage and sintering behaviors of metal and ceramics different from each other could be controlled by the adjustment with respect to the particle size and phase type of zirconia. The residual stresses generated on the metal and ceramic regions in FGM were characterized with X-ray diffraction method, and relaxed as the thickness and number of compositional gradient layer were increased. The residual stress states in TZP/SUS-FGM have irregular patterns by means of the different sintering behavior and cracking at ceramic-monolith. While in ZT/SUS-FGM, compressive stress is induced on ceramic-monolith by the volume expansion of monoclinic ZrO2 at phase transformation. Also, compressive stress is induced on metal-monolith by the constraint of warping which may be created to the metal direction by the difference of coefficient of thermal expansions. As a consequence, it has been verified that the residual stress generated on FGM is dominantly influenced by the thickness and number of compositional gradient layer, and the sintering defects and residual stress can be controlled by the constraint of the difference of shrinkage and sintering behaviors of each component.

Key words: Functionally gradient materials (FGM), Sintering defects, Residual stresses, X-ray diffraction method, Sintering behavior