Rankin and Wright — Ternary System CaO- Al n _0^-SiO v 29 



It is possible to determine the melting temperatures within 

 the field for aCaSi0 3 either by heating curves or quenchings ; 

 the mean values of a number of experiments with each com- 

 position are given in Table II. 



Table II. 



Melting temperature of various compositions within field ^4-5-6-5-2. Pri- 

 mary phase is aCaSi0 3 (M. P. 1540° ±2°). 



^ iCaO 



Composition L, ^ 



Wt. per centjg^ 3 



Temperature 

 of melting 



35 

 5 



60 



1408 



30 



10 

 60 



1322 



40 



5 



55 



1449 



35 

 10 

 55 



1374 



45 

 5 



50 



40 

 10 

 50 



1481 1416 



35 

 15 

 50 



1330 



45 

 10 

 45 



1402 



40 

 15 

 45 



1345 



III. The field of CaO.Al,O z .%SiO—{l-V-5-7-9).— -The 

 region in which CaO.Al 2 3 .2Si0 2 is the stable primary phase 

 possesses a maximum temperature 1550° ± 2° (the melting 

 point of CaO.Al 2 3 .2Si0 3 ). The melting temperatures of 

 various compositions within this field are given in Table III. 



Table III. 

 Melting temperature of various compositions within field 1- 

 phase is CaO.Al 2 3 .2Si0 2 (M. P. 1550° ±2°). 



2-4-74 



►. Primary 



omposition 

 it. per cent 



CaO 



M 2 3 

 SiO, 



15 

 20 

 65 



18 

 21 

 61 



15 

 25 



60 



1447 



20 

 25 

 55 



25 

 25 

 50 



1466 



20 

 30 

 50 



30 



'25 



45 



25 

 30 

 45 



20 

 35 

 45 



1545 



30 



30 

 40 



1445 



25 30 

 35 35 

 40 35 



emperature 

 f melting 





1384 



1358 



1468 



1522 



1433 



1514 



1523 1415 



IV. The field of Al,Si0 5 (J-1-7-I).— Within this field it 

 proved impracticable to determine melting temperatures on 

 account of the extreme viscosity of the melts in portions of the 

 field and of the high melting temperatures in the remainder. 

 But, in spite of this, fairly accurate conclusions can be drawn as 

 to the slope of the melting surface of this field, because the 

 field is rather narrow and the melting temperatures for all 

 sides of the field have been ascertained. 



V. The field of 3Ca0.2SW, (B'-B-6-4).— This field differs 

 somewhat in type from those preceding. In this case the com- 

 pound is unstable and hence its composition lies outside of the 

 field in which it occurs as primary phase. The slope of this 

 narrow field is ascertained from the melting temperatures of 

 its boundaries, which were determined. 



