The Effect of Pressed Density on Fired Density of Alumina Compacts

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J. Korean Ceram. Soc. > Volume 19(2); 1982 > Article

Journal of the Korean Ceramic Society 1982;19(2): 115.

알루미나의 성형밀도가 소성밀도에 미치는 영향

김해두, W.F. FORD

연세대학교 요업공학과

The Effect of Pressed Density on Fired Density of Alumina Compacts

ABSTRACT

The main objective of this work was to study the efTect of pressed density of pellets prepared from an oxide powder on their fired density and to prove experimentally the parabolic relationship proposed by FORD. A-I6 and A-J7 alumina powders. which showed quite dlfrerent powder characteristics but were essentially very reactive powders, were employed, and a series of pelIets weIe pressed in a 1l.2mm diameter hardened steel die with a hydraulic press and a mechanically operated press in order to obtain a wide range of pressed demity. Density ranges from 35 to 65 % theoretical for A-16, and 46 to 66 % theoretical far A-17 were obtained and the highest pressed density achieved using lubricant was 67.8 % theoretical. CompactlOn mechanisms for A-16 and A-I 7 were deduced. Several plots of ($D_F$-$D_P$) against DpjDT showed reasonable parabola and temperature dependence and the maximum density increase occurred when the pressed density was approximately 50% theoretical. The parabolic relationship was confirmed by linear plot of ($D_F$-$D_P$) against (1-$frac{D_P}{D_T})$).