Abstract
(1) The specific volume change during solidification of the elements and the atomic number can be shown by periodic relation.
(2) It is very interesting to note that in the second-fifth periods of the Periodic Table, there exist elements which expand during solidification, such as Si, Ga, Sb and Bi; the expansion of Si has been found by the present author.
(3) The volume changes during solidification of five compounds, Zn4Sb3 (Zn 41.72%) Zn3Sb2 (Zn 44.61%) Mg2Sn (Sn 70.93%) MgZn (Zn 84.32%) and CuAl2 (Cu 54.10%) have been measured. It has been found that the compounds Zn4Sb3, Zn3Sb2 and Mg2Sn expand for 1.76% 1.65% and 0.70% respectively, while the compounds MgZn2 and CuAl2 shrink for 23.76% and 3.12% respectively, the shrinkage of MgZn2 being very much largar than that of the other metals, these results do not agree with the calculated values by the mixture rule, this may bear an interesting property of the metallic compound.
(4) The specific volumes in the liquid and solid states of the Zn-Sb system are very much larger than the calculated values by the mixture rule, but by calculating the volume changes of compounds of the Zn-Sb system during solidification as in the case of the previous calculation in the Pb-Bi system, the calculated values agree well with the observed values. From this result. it seems that the abnormal volume changes of Mg2Sn and MgZn2 are due to difference in specific volumes between the liquid and solid states trom the calculated values.
(5) The volume shrincages of η (Cu3Sn, Cu 61.64%) and δ (Cu31Sn8, Cu 67.50%) compounds of the Cu-Sn system during formation from the β solid soltion have been measured. The shrinkage of Cu3Sn (1.19%) and δ (0.43%) is very large for the volume change of the solid phase and δ has an important relation with the casting of the gunmetal.
