Analysis of Grain Boundary Oxidation in <TEX>$(Ba, Sr)TiO_3$</TEX>-based PTCR Ceramics by <TEX>$mu-AES$</TEX> and <TEX>$DV-Xalpha$</TEX> Energy Simulation

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J. Korean Ceram. Soc. > Volume 31(6); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(6): 587.

$(Ba, Sr)TiO_3$계 PTCR 세라믹스의 입계산화에 대한 $mu-AES$ 분석 및 $DV-Xalpha$ 궤도에너지 계산모사

김명철, 강영석¹, 허수형¹, 박순자¹

군산대학교 공과대학 재료공학과
¹서울대학교 공과대학 무기재료공학과

Analysis of Grain Boundary Oxidation in $(Ba, Sr)TiO_3$-based PTCR Ceramics by $mu-AES$ and $DV-Xalpha$ Energy Simulation

ABSTRACT

(Ba, Sr)TiO3-based PTCR ceramics were sintered and cooled down with various cooling conditions in the air. AES was applied to investigate the composition change in the grain boundary and bulk area of oxidatively cooled samples. Ba component was deficit in grain boundary region, while oxygen was abundant than bulk region. The discrete changes of oxygen binding energies were confirmed in the grain boundary region of the heavily oxidized samples. It was supposed that the large binding energy shift resulted from the oxidation of the segregated Mn in grain boundary region and this idea was supported by the DV-X$alpha$ molecular energy simulation.