Труды КНЦ вып.9 (ХИМИЯ И МАТЕРИАЛОВЕДЕНИЕ вып. 1/2018(9) часть 1)

1004) 1010 ъ С - с ■ u □ о 0 L ' Л Д д Д д A A Д Д A i i 1 , 1 i i i . 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 x(LaF,) Fig. 1. Schematic phase diagram of the (LiF — CaF 2 )eut — LaF 3 m°lten system Fig. 2. Schematic phase diagram ° f the (LiF CaF 2 )eut — SmF 3 m°lten system Fig. 3. Schematic phase diagram ° f the (LiF — CaF 2 )eut — GdF 3 m°lten system Fig. 4. Schematic phase diagram ° f the (LiF CaF 2 )eut— NdF 3 m°lten system Based °n the schematic phase diagrams it is clear t° see that investigated systems with excepti°n ° f (LiF — CaF 2 )eut — SmF 3 are n°t simple eutectic °nes. Eutectic temperatures vary between appr°x. 989 K f°r system with LaF 3 , 935 K f°r system with SmF 3 , 925 K f°r GdF 3 and 965 K f°r system with NdF 3 . Based °n the previ°usly rep°rted data c°ncerning the presence ° f peritectic p°int in the LiF — CaF 2 — LaF 3 m°lten system [1] and f°rmati°n ° f s°me ternary phases like Ca 0 , 65 La 0 , 35 F 2,35 and Ca 0 , 9 Lac, 1 F 2 , 1 , the f°rmati°n ° f ternary flu°rides was expected in the (LiF — CaF 2 )eut — LaF 3 . H°wever XRD patterns ° f s°lidified samples fr°m thermal analysis sh°wed n° °ther crystalline phase except the initial °nes. Inf°rmati°n ab°ut XRD analysis and further inf°rmati°n ab°ut the phase diagram c°uld be f°und in °ur published w°rk [23]. In the quasi-binary system (LiF — CaF 2 )eut. — SmF 3 the f°rmati°n ° f °ther phases fields was °bserved as expected based °n results ° f CaF 2 — SmF 3 system. In °rder t° estimate whether s°me new phases c°uld be formed XRD patterns ° f the s°lidified samples were rec°rded. The intensity ° f the additi°nal diffracti°ns changes with the increasing c°ntent ° f SmF 3 indicating the f°rmati°n ° f s°me new c°mp°nent °r even m°re c°mp°nents. Final c°mplicati°n arises fr°m the shift ° f s°me diffracti°ns indicating the f°rmati°n ° f s°lid s°luti°ns. Measured experimental data ° f primary crystallisati°n temperatures in the (LiF — CaF 2 )eut — GdF 3 indicate the existence ° f simple binary system; h°wever it is pr°bably n°t the case and these data represent similar situati°n as in the system ab°ve i. e. the f°rmati°n ° f s°lid s°luti°n fields. This increased tendency t° form additi°nal phases is visible als° fr°m analysis ° f XRD patterns ° f the s°lidified samples. The presence ° f GdF 3 was n°t °bserved as the m°st pr°bably it reacts with either LiF °r CaF 2 °r b°th. The f°rmati°n ° f °ther phases (unidentified) is als° highly pr°bable as s°me unidentified diffracti°ns were °bserved in s°lidified samples and their intensity change with c°ncentrati°n variati°n. S°lid-s°lid phase transf°rmati°n ° f pure GdF 3 was rep°rted at temperature 1172 K [24] °r at 1310 K [22]. System (LiF — CaF 2 )eut. — NdF 3 is m°re similar t° the system (LiF — CaF 2 )eut. — SmF 3 as t° the gad°linium anal°gue. It is evident that Nd system sh°ws similar features like Sm system; °nly initial phases in s°lidified samples were identified (t°gether with s°me NdOF impurities) and the f°rmati°n ° f any °ther kn°wn ternary flu°rides was °bserved, in c°ntrast t° Gd system. H°wever, the presence ° f unidentified diffracti°ns indicates t° the f°rmati°n ° f s°me new phases. Detail analysis ° f °btained results are summarized in [25]. 419