금속의 응고현상과 유사한 염화암모늄용액을 사용하여 가압시의 결정성장에 관한 고찰을 수행하였다. 약 37% 염화암모늄용액을 사용하였으며, 주입온도에 따른 가압 및 무가압에서의 응고과정을 관찰하였다. 가압과 무가압에서 응고과정의 변화는 다음과 같았다. (1) 가압하에서 dendrite fragmentation은 촉진되었으며, 냉각속도는 훨씬 빠르게 진행되었다. (2) 결정성장속도 또한 가압에 따라 증가하였다. (3) Sweeping effect는 가압시에 현저하게 나타났다. (4) 가압시 금형벽 주위의 등축정대 또는 주상정대의 recess는 결정성장을 촉진시켰다. (5) 낮은 주입온도에서 등축정대는 주로 동시 핵생성(simultaneous nucleation)에 의해서 형성되었으며, 높은 주입 온도에서는 주로 대류(convection)에 의해서 형성되었다. 이 효과는 가압시에 더욱 촉진시켰다,

This work was carried out for some observations on crystal growth under pressure in an ammonium chloride/water analogue system, with a view to explore possible similarities with the mode of solidification in metals. An ammonium chloride solution having 37% wt. composition was used, and crystallisation phenomena were observed in this solution frozen at atmosphere and under pressure, depending on the pouring temperatures. Crystallisation phenomena under pressure greatly differed from the ones at atmosphere; they were as follows; (i) Cooling rate was much faster under pressure than that at atmosphere, stimulating dendrite fragmentation. (ii) Growth rate of columnar and/or equiaxed grains was increased under pressure. (iii) A sweeping effect ahead of the advancing interfaces was much more effective under pressure. (iv) A recess of columnar or equiaxed zone near the mold wall by applying pressure stimulated the formation of new crystals, but this was not in atmosphere. (v) Equiaxed zones were formed mainly by simultaneous nucleation at the lower pouring temperature, and at the higher ones mainly by convection. These effects were more effective under pressure.