弗素リヒテライト組成ガラスにおける結晶核生成と結晶成長
弗素リヒテライト系石綿組成ガラスの結晶化に関する研究 (第3報)
1970 年 78 巻 895 号 p. 92-100
詳細
1970 年 78 巻 895 号 p. 92-100
Nucleation and crystal growth in fluor-richterite composition glass were studied by the electron and optical microscopy and X-ray powder diffraction method. The following results were obtained.
1) As evidenced from a greater number and a smaller size of crystallites, the apparent nucleation rate was larger in the glass sample that was subjected to the heat treatment for glassy phase separation before being subjected to those for nucleation and crystal growth than in the sample that was not subjected to the heat treatment for the phase separation.
2) The temperature corresponding to maximum rate of nucleation of fluor-richterite was in the range from 725°C to 750°C for the glass subjected to the phase separation heat treatment and at 763°C for the glass not subjected to the heat treatment. The apparent activation energy for the nucleation was 110kcal/mole in the former case and 66kcal/mole in the latter.
3) The rate of crystal growth of fluor-richterite was maximum at 1000°C and activation energy for the growth was 142kcal/mole.
4) Two glassy phases formed by the glassy phase separation and a crystalline phase (“fluor-talc”) were present in the sample heat-treated at the temperatures under 750°C. Subsequent crystallization of fluor-richterite seemed to be governed by occurrence of these three phases. More specifically, crystallization of fluor-richterite appeared to start at the interface between two separated glassy phases and/or at the surface of “fluor-talc” crystals.
