Syntheses and structural characterization of zirconium-tin and zirconium-lead binary and ternary systems.

摘要

The binary zirconium-tin system was reinvestigated. The A15 phase appears to be a line phase with a Zr(sub 4)Sn composition. The Zr(sub 5)Sn(sub 3) (Mn(sub 5)Si(sub 3)-type) and Zr(sub 5)Sn(sub 4) (Ti(sub 5)Ga(sub 4)-type) compounds are line phases below 1000(degree)C, the latter being a self-interstitial phase of the former. ZrSn(sub 2) is the tin-richest phase. There is an one-phase region between these phases with partial self-interstitials at high temperatures. The zirconium-lead system behaves similarly: there are an A15 phase with a Zr(sub (approximately)5.8)Pb composition, Zr(sub 5)Pb(sub 3) (Mn(sub 5)Si(sub 3)-type) and Zr(sub 5)Pb(sub 4) (Ti(sub 5)Ga(sub 4-type)) compounds, and a high temperature solid solution between Zr(sub 5)Pb(sub >3.5) and Zr(sub 5)Pb(sub 4) from below 1000(degree)C; however, the ZrSn(sub 2) analogue is not formed. The Mn(sub 5)Si(sub 3)-type phases in these systems can accommodate third elements interstitially to form stoichiometric compounds Zr(sub 5)Sn(sub 3)Z (Z = B, C, N, O, Al, Si, P, S, Cu, Zn, Ga, Ge, and As and Se) and Zr(sub 5)Pb(sub 3)Z (Z = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ag, Cd, In, Sn, Sb and Te) as well as their self-interstitial derivatives. The systems Zr-Sn-T, T = Fe, Co and Ni, did not produce stoichiometric interstitial phases Zr(sub 5)Sn(sub 3)T. Instead, the interstitial phases for these elements are formed only with excess tin that partially occupies the interstitial site together with a T element. Reducing the amount of tin in these systems yields two new phases; Zr(sub 5)Sn(sub 2+x)Fe(sub 1-x) (0 (le) (times) (le) 0.28) (W(sub 5)Si(sub 3)-type) and Zr(sub 6)Sn(sub 2)Fe (Zr(sub 6)Al(sub 2)Co-type) as characterized by X-ray single crystal analyses. A cobalt analogue for the latter was also synthesized.