In this work the enthalpies of decomposition and formation of some Zr-Al intermetallic compounds are determined by vapor pressure measurements. This kind of data can be of interest for the simulation of the behaviour of these phases under real application conditions. The manuscript can be suitable for publication after the authors carefully checked the issues below. The most important points are labelled by an asterisk *.

Figs 2 and 3 should be cited in the text before than in the present version. Fig 1 could be cited at the end of section 2.1, figure 3 at line 17 of section 2.2

In section 3.1 line 42, isotopic abundance is mentioned, whereas Al is a monoisotopic species

About the calibration with Aluminum, it should be specified the crucible that was used and the temperature range covered (using solid Al, the range is expected to be outside the range of measurements on aluminides)

page 6, line 57-58, please check the reference number for the work by Kematick, [34] rather than [40]

page 7 line 14-15 add “K” after 1350

• while the numerical result could be reasonably close to the corrected one, the procedure used by authors to calculate the average of second law enthalpies at mean T seems questionable (see for example Table 4), because the individual values on which the mean is calculated are at different temperatures, so they are not expected to be the “same” value. The average should be calculated after shifting all the experimental values to the average temperature of all the runs.

*The difference between II and III law decomposition enthalpies is rather high. Did authors note that the Neumann-Kopp law implies using the Cp of pure solid Al in a temperature range (i.e., the range of their experiments) where Al is liquid ? Please check the use of appropriate data for the calculation of Gibbs energy functions for third law analysis.

• It is not clear in Table 6 if the experimental values of formation enthalpies are all at 298 K. More important, in Table 7 the formation enthalpy is given apparently at 1347 K (see the table heading), whereas in the caption 298.15 K is reported. Furthermore, footnote “a” is lacking. Please check accurately these numbers.

*In the paper by Murray (ref 10) the heats of formation given in the work by Kematick (ref 34) were significantly corrected due to a calculation error made in ref 34 (see table 4 and text in the paper by Murray). Do tables 6 and 7 of the present manuscript take into account this correction ? Note that the correction is as high as 24 kJ/mol for ZrAl 2 and 40 kJ/mol for Zr2Al3, whereas in table 6 the values from ref 34 and 10 are reported to be the same and in table 7 only a difference of 5.6 kJ/mol results. Please check.

Typo: Meidema for Miedema