Abstract
Effects of agitation and heating rate on crystallinity, size distribution and mean size of $\alpha$-$SiO_2$powder prepared hydrothermally were investigated. $\alpha$-$SiO_2$crystalline powder, in mean particle size of 1~3.2 $\mu\textrm{m}$, was obtained at $350^{\circ}C$ using KOH as a mineralized for a 3 h reaction. Experimental results showed that particle size became smaller as the rate of agitation increased if it was introduced from the beginning of reaction, however, crystallinity was reduced at the low rate of agitation and it was became enhanced at above 150 r/min. Particle size became larger if agitation was introduced at any time during the reaction rather than introduced from the beginning of reaction. It was also found that particle size became smaller if heating rate was reduced, while the rate of agitation kept constant.
수열합성법을 이용한 $\alpha$-$SiO_2$ 단결정 분말 제조시 교반의 추가와 승온속도의 변화가 입자의 결정성, 입도분포 및 평균입경에 미치는 영향을 조사하였다. KOH를 광화제로 사용하였으며, $350^{\circ}C$에서 3시간 동안 반응을 시켜 평균입자 크기가 1~3.2$\mu\textrm{m}$인 결정 분말을 제조하였다. 실험결과 반응초기부터 교반을 한 경우에는 교반속도가 증가함에 따라 평균입경이 감소했으나, 결정성은 나빠지다가 150r/min 이상에서는 다시 좋아졌다. 또한 반응 도중에 교반을 추가하면 반응초기부터 교반을 한 경우보다 입자의 크기가 커졌다. 그러나 교반속도를 일정하게 한 후 승온속도를 느리게 하면 입자의 크기가 작아졌다.
