System peritectic point

The copper-zinc system shown in Fig. A1.38 has no fewer than five peritectic reactions. Locate them and ring the peritectic points. (Remember that when a single-phase field closes above at a point, the point is a peritectic point.)... 

PERITECTIC TEMPERATURE. Temperature in a peritectic system at which there is equilibrium between the solid and the remaining melt, the composition of which conforms to the peritectic point, at which the temperature line meets the liquids curve. 

The vertical projection of the phase diagram of this system is shown in Figure 3.34. The phase diagram has four planes pc(A), pc(B), pc(C), and pc(ABC), which are the projections of the planes of primary crystallization of the compounds A, B, C, and ABC, respectively. The figurative point of the ternary compound ABC lies outside the plane of its primary crystallization. In contrary to the previous case, the phase diagram of this type has only one ternary eutectic point Ct and two singular points, which are the ternary peritectic points Ptj and Ptj. The boundary lines Ptj-et and Ptj-et represent the simultaneous crystallization of components B and ABC, and C and ABC, respectively. 

The phase diagram was calculated from the binary boundaries and from the quaternary mixtures measured, therefore the standard deviation of the fit is not given. The calculated phase diagram of this system is shown in Figure 3.53. The experimentally determined phase diagram measured by Chernov and Ermolenko (1973) is probably not quite correct because of little experimental data in the region of the presented peritectic point. 

Figure 12 Solidlliquid phase diagram for the binary water-NaCl system. The dihydrate that separates at the euteetie point is unstable, i.e. it has no melting point but deeomposes into anhydrous erystalline NaCl and water (ice) at a peritectic point...

The liquidus surface taken from [1988Ray] which is based onthe workof [1932Koel] is presented in Fig. 2. As mentioned above, the invariant L + (Mo) a + p is unlikely to exist in the system. This is removed from the original liquidus surface as presented by [1932Koel]. Instead, there is now a monovariant connecting the binary peritectic reactions related to the formation of the a phase in the Fe-Mo and Co-Mo systems. It is also necessary to add a monovariant related to the peritectic formation of the R phase in the Fe-Mo system. This line is shown to meet the monovariant line from the peritectic point in the Co-Mo binary associated with the formation of the p phase. At this intersection, a new monovariant joins the monovariant... 

Figure 5 The scheme of the solubility polytherm of the host(H) - guestl (gl) - guest2(g2) system tgi - the peritectic point of the clathrate with guestl, tg2 the peritectic point of the clathrate with guest2.

Shiflet et al. (1979) have applied the Kaufman approach to the calculation of the Tb-Ho phase diagram and have compared their results with those obtained experimentally by Spedding et al. Their calculated peritectic point in this system fell at a somewhat lower temperature and holmium concentration than did the experimentally determined peritectic point. 

Shiflet et al. (1979) combined the Kaufman approach with values of the enthalpies and entropies of melting and transformation of the pure rare earth metals and calculated the phase diagram for the Tb-Er system. The peritectic point in the... 

The section Ce2Se3-SnSe (fig. 16) is a quasi-binary section of the ternary system Ce-Sn-Se and belongs to a peritectic type with limited solid solutions based on SnSe (Murguzov et al. 1986). The parameters of the peritectic point are 70 mol% SnSe and 870 5°C. The ternary compound Ce2SnSe is formed according to the reaction... 

Two versions of the Ba-Cd phase diagram are very similar and, but for some minor differences in the critical point parameters, differ only in the stoichiometry of the compound at 17 at% Ba-Ba2Cd9 or BaCd . Since ref. 5 includes a structural analysis of the intermediate compounds, this phase diagram is recommended. There are five intermediate compounds in the system. Four of these melt congruently, BaCd (SSS C), BaCdj (642°C), Ba2Cd, (620°C) and BaCd (672°C) the other, BajCd (409°C), is formed in a peritectic reaction. The existence of Ba2Cd BaCd, BaCdj, and BaCd], has been verified in separate crystallographic studies. 

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