Liquidus point

Figure 4.4. Liquidus points for Cu-Sn determined by Heycock and Neville (1890, 1897).

The constraints imposed upon the interaction coefficients in the A-C binary are given here. Those for the B-C binary can be obtained by analogy. The constraints generally serve to reduce the number of independent coefficients and at the same time insure that the liquid model will match selected experimental values exactly regardless of how well the liquidus points and other data can be fit. 

For the liquidus of InSb(s) there are 13 points from thermal analysis, which include a eutectic point at 494 + 0.5°C and xSb = 0.69 (Liu and Peretti, 1952), as well as three points from dissolution experiments by Hall (cited in Shunk, 1969). The best-fit interaction coefficients, the fit to the liquidus line of InSb(s), eutectic temperature and composition are given in Table II. It is emphasized that the values of the interaction coefficients are such that Eqs. 

Fig. 8. Calculated enthalpy of mixing of Ga-Sb melt at 721.9°C and experimental points from Gambino and Bros (1975). Curve 1 is fifth-power polynomial fit from Ansara et al. (1976). Curve 2 is our calculation with associated solution parameters giving the best compromise fit to the enthalpy of mixing and the liquidus points. Curve 3 is calculated using the subregular solution model and parameters given in the text.

The calculated liquidus isotherms for the Hg-Cd-Te system in Fig. 28 show that the liquidus temperature is not always a maximum in the HgTe-CdTe pseudobinary section. Figure 38 shows the liquidus surface between this pseudobinary and the Hg-Cd axis in more detail for comparison with ten experimental ternary liquidus points obtained by Szofran and Lehoczky... 

Strauss, A. J. (1967). Private communication of tabulated liquidus points, presented in graphical form in Harman (1967). 

When a liquid solution is cooled slowly, temperature will eventually reach the liquidus point, and a solid phase will begin to separate from the liquid solution. 

Voltages of the sample thermocouple corresponding to thermal arrests were converted to temperatures using N.B.S. Circular No. 561 (17). Table I hsts the temperatures of thermal arrests for the entire range of composition between 0 and 100 mole % UFg. The values listed in Table I are averages of several measurements, and the uncertainty values are standard deviations of the averages. The uncertainty values associated with the liquidus points obtained by the extrapolation procedure (i) have not been estimated. 

End of the 19th Century. This marked the development of the first high speed steels (produced by quenching the steel just below the liquidus point) by Taylor and White. 

The required reaction or fusion temperature is determined from the phase diagram. As a minimum, this temperature must be higher than the liquidus point of the alloy product. Preferably, however, it should exceed the meltii points of all the reacting metals. The best temperature is one which exceeds the liquidus point by 30-50 °C over the entire range of compositions of the system. Such a temperature will certainly ensure proper reaction conditions. 

The triple-point or three-phase line in Fig. 8 extends between the limits of 68.97 0.1 °K and 2.74 0.1 psia to 68.82 0.1 °K and 2.90 0.1 psia. Since the triple point of pure argon is 83.77°K, a triple-point depression of approximately 15°K (27 R) was observed. The upper end of the three-phase line, from the point of view of pressure, is the end point of the solid-liquid and liquid phase boundary, or the liquidus point. If this point is compared with the data of Long and DiPaolo [ ], as presented by Cook [ ], the agreement is within the accuracy with which the plot presented can be interpreted. 

Reflow The solder paste temperature exceeds the liquidus point and reflows, wetting both the component leads and the board pads. Surface tension effects occur, minimizing wetted volume. 

Cooling The solder paste cools below the liquidus point, forming acceptable (shiny and appropriate volume) solder joints. 

Figure 13.14 Freezing and meiting as examples of liquid-solid transition in bulk material [R- = oo). Representation of the T-C diagram of a small particle at fixed dimension Ri < Ri (solubility curve is shown for liquidus). Point Pi indicates the initial composition Co before nucleation, point Pi characterizes equilibrium composition Cp...

There must be sufficient thermal energy to allow wetting to occur—typically 35° to 50°C above the Liquidus point of the alloy being used. 

Figure 42.1 shows a soldering alloy pellet put onto the surface of a metal plate, which has been previously fluxed and heated to a temperature at least equal to the Liquidus point of the alloy, where ... 

Silicide solvus Calculated liquidus point Density(a)... 

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