The system lime-boric oxide-silica

Abstract

The equilibrium diagram for the system CaO-B20 a-Si02, constructed from data on 200 ternary compositions, is presented. The portion of the diagram imme- diately adjacent to the binary system B2 0 a-Si02 is incomplete. A unique fea- ture of the system is the appearance of an area of liquid immiscibility extending across the diagram from the lime-silica side to the lime-boric oxide side and crossing the fields of silica, monocalcium borate, and calcium diborate. A newly established ternary compound, 5CaO.B2 0 a.Si02, melts congruently at 1,4190 C. Tricalcium silicate does not appear at the liquidus in the ternary system. Di- calcium silicate forms partial solid solutions with calcium borates whereby the 0I.-{3 inversion temperature is lowered by a maximum of 190 C.