Ca₃(PO₄)₂-MgSiO₃系の相関係

抄録

Phase relations in the system tricalcium phosphate (3CaO⋅P₂O₅=C₃P)-enstatite (MgO⋅SiO₂=MS) have been investigated in the temperature range 1100 to 1600°C by means of the quenching method. C₃P takes β-type (whitrockite) in a wide region by dissolution of MgO, and diopside (d) appeared in the composition range more than 40mass% C₃P by a reach in between MgSiO₃ and liberated CaO. The enstatite transfers to iron-free pigeonite (pi) by taking CaO in an MS-rich region, where pi coexists with protoenstatite, MgSiO₃ (pr). Primary crystals which appeared in a wide region are β-C₃P and pi, and primary diopside appears in a narrow region at a minimum temperature (1265-1305°C). In the subsolidus region below 1245°C, β-C₃P coexists with d, pi or pi-pr mixture. The system is not binary and it should be discussed from the ternary system C₃P-M-S and the quaternary system C₃P-CMS₂-MS-S.