New aspect of the solid phase equilibria in the ternary PbSnCa system for xCa≤25 at.%

✍ Scribed by J. Hertz; C. Fornasierie; J.P. Hilger; M. Notin

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 694 KB
• Volume: 46
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/0378-7753(93)90027-x

✦ Synopsis

New crystallographic data prove that CaPb, and Sn,Ca-Lla compounds belong to the same single-phase Ca(Pb, Sn), domain in the ternary Pb-Sn-Ca equilibrium phase diagram. A tentative calculation of this diagram shows that about 2 wt.% Sn, introduced in the cu-Pb matrix, allows a decrease in the solubility of Ca at 400 K from lo-' to lo-' wt.%. Simultaneously, the LIZ compound, in equilibrium with the a-Pb matrix, crosses very rapidly the x, =0.25 line, continuously from the Pb-Ca border to near the Sn-Ca border, when increasing the Sn content in the (I matrix from zero to 8 wt.% Sn at 400 K. A very large triangle formed by the three phases a-Pb (8 wt.% Sn), &Sn (1.7 wt.% Pb), CauPbSSnrL1, appears in this diagram at 400 K. This triangle provides a ternary eutectic, calculated at 424 K. This calculation brings to light some reasons for the process transition for the hardening of Pb-Ca grid-battery alloys, from discontinuous to continuous, when increasing the tin content.