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Effect of Mold Dimensions on Temperature Distribution of Sintered Body during Plasma Activated Sintering Gil-Geun Lee Div. of Materials Science and Engineering, Pukyong National University, San 100, Yongdang-Dong, Nam-Gu, Busan 608-739, Korea ABSTRACT In the present study, the focus is on the analysis of the effect of the mold dimensions on the temperature distribution of a sintered body during plasma activated sintering. The temperature distribution of a cylindrical mold with various dimensions was measured using K-type thermocouples. The temperature homogeneity of the mold was studied based on the direction and dimensions of the mold. A temperature gradient existed in the radial direction of the mold during the plasma activated sintering. Also, the magnitude of the temperature gradient was increased with increasing sintering temperature. In the longitudinal direction, however, there was no temperature gradient. The temperature gradient of the mold in the radial direction decreased with increasing inner diameter of the mold and its length. INTRODUCTION The plasma activated sintering process has been used for preparing various functional materials, including nanostructured materials, composite materials, magnetic materials, and others [1]. The thermal energy for plasma activated sintering is obtained from an external electric current. In powder sintering, the use of an electric current is known to enhance the sintering kinetics, and therefore, high densities are achieved at low temperature or in shorter times compared to conventional sintering methods. In general, the external electric current is applied to the punch and passes through the powder and die. The passage of the electric current provides resistive heating of the powders and die by the Joule effect; that is, the electric power is used as the heating source for consolidating the compact. The powder characteristics; i.e., conductivity, size distribution and morphology, affect the Joule effect. Also, the degree of the Joule effect depends not only on the powder characteristics but also the punch and die; i.e., material, size and morphology, and other factors [2]. A homogeneous temperature distribution in the compact during plasma activated sintering is very important to obtain high performance functional materials with large dimensions. The temperature distribution of the compact when applying the external electric current depends on

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the Joule effect of the powder and die. During plasma activated sintering, however, it is difficult to maintain a homogeneous temperature distribution in the large compact due to short sintering time [3]. Until now, the determination of mold dimensions for plasma activated sintering has been carried out in light of experience. For practical plasma activated sintering applications, the relationship between the temperature distribution and mold dimensions should be verified. In the present study, to obtain a basic guiding principle for the design of the mold for the plasma activated sintering, the homogeneity of