Abstract
The sintering behaviors of the renewed $Al_2$O$_3$ceramics were investigated as functions of the addition amount and particle size of recycling $Al_2$O$_3$powder, such as crushed powder of structural $Al_2$O$_3$ceramics and waste $Al_2$O$_3$adsorbent, were investigated. Pure $Al_2$O$_3$sample was fabricated by sintered at 1,$650^{\circ}C$ for 5h and it was crushed into powder (-40${\mu}{\textrm}{m}$and +40${\mu}{\textrm}{m}$ in particle size) by thermal shock treatment and crushing. Then, 10~50wt% of crushed $Al_2$O$_3$powder and waste $Al_2$O$_3$adsorbent were mixed with pure $Al_2$O$_3$powder and were subjected to re-sintering to renewed $Al_2$O$_3$sample. The density and the 3-point bending strength increased with increasing the sintering temperature without regard to the addition amount and particle size of recycling $Al_2$O$_3$powder, and that of the samples at the same sintering temperature decreased with increasing the addition amount and particle size of recycling $Al_2$O$_3$powder. Samples over 200 Mpa of 3-point bending strength were obtained by mixing ~30wt% of crushed $Al_2$O$_3$powder(-40${\mu}{\textrm}{m}$), ~20wt% of crushed $Al_2$O$_3$powder (+40${\mu}{\textrm}{m}$) and 10wt% of waste $Al_2$O$_3$adsorbent. 5~20wt% of waste glass powder containing renewed $Al_2$O$_3$samples for densification were fabricated by sintered at 1200~1$650^{\circ}C$ for 5h. The temperature of maximum density and 3-point bending strength decreased with increasing the addition amount of waste glass powder, however, these samples at above 140$0^{\circ}C$ showed lower density and bending strength than renewed $Al_2$O$_3$samples. The addition of waste glass powder did not improved the densification of renewed $Al_2$O$_3$sample.
재활용 $Al_2$O$_3$분말인 구조재료용 $Al_2$O$_3$세라믹스의 분쇄분말과 폐Al$_2$O$_3$흡착제의 첨가량과 입경에 따른 재생 $Al_2$O$_3$세라믹스의 소결특성을 조사하였다. 1,$650^{\circ}C$에서 5시간 소결한 순수 $Al_2$O$_3$시편을 급랭하여 분쇄한 -40과 +40$\mu$m의 $Al_2$O$_3$분말과 폐Al$_2$O$_3$흡착제를 순수한 $Al_2$O$_3$분말에 10~50wt% 첨가한 후, 재소결하여 재생 $Al_2$O$_3$세라믹스를 제조하였다. 재활용 $Al_2$O$_3$분말의 첨가량과 입경에 관계없이 소결온도가 증가함에 따라 시편의 밀도와 3점곡강도는 증가하였으나, 동일 소결온도에서는 재활용 $Al_2$O$_3$분말의 첨가량이 증가함에 따라 밀도와 3점곡강도는 감소하였다. ~30wt%의 $Al_2$O$_3$분쇄분말(-40$\mu$m), ~20wt%의 $Al_2$O$_3$분쇄분말(+40$\mu$m) 및 10wt%의 폐Al$_2$O$_3$흡착제를 첨가한 시편의 3점곡강도는 200MPa 이상이었다. 재생 $Al_2$O$_3$시편의 치밀화를 위하여 5~20wt%의 폐유리분말을 첨가하여 1200~1$650^{\circ}C$에서 5시간 소결한 시편은 폐유리분말의 첨가량이 증가함에 따라 최대 밀도와 3점곡강도를 나타내는 온도는 감소하였으나, 140$0^{\circ}C$이상에서는 페유리분말을 첨가하지 않은 시편에 비하여 밀도와 3점곡강도가 감소하여 재생 $Al_2$O$_3$세라믹스의 소결성 향상에는 기여하지 못하였다.