硝酸塩水溶液中におけるカルサイト単結晶の水熱育成

概要

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Calcite single crystals could be hydrothermally grown in newly discovered NH_4NO_3 solution even at 150℃. The solubility of calcite in NH_4NO_3 solution was 4.0 g/l at 100℃ and 30 MPa, and increased with increasing temperature and pressure. The dislocation densities of grown calcite crystals on as-cleaved and etched seeds were 4×10^5 and 2×10^4 cm^<-2>, respectively. The growth rate on etched seeds was dependent upon both growth temperature and concentration of solution. The maximum growth rate was 45 μm/day in 0.2 M NH_4NO_3 solution at 200℃ and 15 MPa. Calcite crystals grown on etched seeds had the same order of dislocation density as that of high grade natural crystals, and were free from OH^- and NO^-_3 ions. This moderate growth condition allows us to employ a Teflon liner for avoiding the contamination from the pressure vessel to grow the optical grade of calcite single crystals.
社団法人日本セラミックス協会の論文
1993-01-01