上游充通大学 SHANGHAI JIAO TONG UNIVERSITY Binary System In condensed systems,modest variations in pressure In general system containing do not appreciably alter phase relationships gases,pressure is important Degrees of freedom available in the system(F): F=C-P+1 F=C-P+2 F:the number of system variables that we may freely vary,or arbitrarily fix C:components P:phase C=2 P=1,F=2 单相区 P=2,F=1 平衡线包围的两相区 P=3,F=0 三相平衡线In condensed systems, modest variations in pressure do not appreciably alter phase relationships In general system containing gases, pressure is important