セラミック中子用シリカ粉のアルカリ水溶液への溶解性

抄録

  Dissolution of the fused silica. α-cristobalite and α-quartz flour into the alkaline aqueous solution was studied. From the results, the fused silica flour is easy to dissolve into the alkaline solution comparing with the others. Caustic soda is better for the dissolvent of the silica than potassium hydroxide.
  The dissolution rate is lowered by proceeding the crystallization of the fused silica to cristobalite. However, many microcracks generates in the cristobalite layer transformed from the fused silica. The contact area of the silica particle with the dissolvent becomes to spread due to the permeation of the alkaline solution into the cracks. Therefore. the phenomenon of the crack formation is useful for promoting the removability of the ceramic core from the casting.