Thermal expansion of lead-antimony alloys

Abstract

This paper gives the rcsults of an investigation of the linear thermal expansion of cast lead-antimony alloys containing from 2.9 to 98.0 percent of antimony. Observations were made at various temperatures between -12 and +200 0 C and are shown in figures 3 to 5, inclusive. A majority of the curves obtained on cooling lie bclow t he expansion curves obtained on heating. The deviations between these curves are particularly noticeable for the alloys containing up to 15 percent of antimony which were cast in a preheated steel mold and cooled slowly. The deviations are less noticeable for the a lloys of higher antimon y content which were cast either in a sand mold or a chill mold. It is probable that the deviations indicate a lack of equilibrium in the samples on account of the effect of the casting conditions or of the chemical composition. Table 3 gives the coefficients of expansion, the change in length after heating and cooling, and the densities of the alloys. Equations 1 to 5 give linear relations between the coefficients of expansion and the atomic percentage of antimony of the lead-antimony alloys containing from 4.8 to 97.0 atomic percent of antimony (2.9 to 95.0 percent, by weight), and show that the coefficients of expansion decrease linearly with increase in the atomic percentage of antimony. The densities of the lead-antimony alloys also decrease linearly with increase in the atomic percentage of antimony. These linear relations a re typical of relations for other properties of binary alloys having structures composed of solid solution + eutectic. The coefficient s of expansion of the lead-antimony alloys cover a wide range of values. It is possible to select lead-antimony alloys that have approximately the same coefficients of expansion as iron, nickel, gold, copper, silver, aluminum, magnesium, and many of thei r alloys