The silver–indium system: thermal analysis, photomicrography, electron microprobe, and X-ray powder diffraction results

Abstract

In the system Ag-In, the isothermal phase transformation at 281 "C previously assumed by Weibke and Eggers has been found not to exist. Metastability of they phase and of the indium phase is persistent at room temperature. The boundaries of the intermediate phases have been redetermined. At room temperature, the equilibrium y phase (hexagonal) exists between 71.0 and 70.3 % silver. At 325 "C and higher temperatures, the y-phase region extends to higher indium concentrations than those given by Weibke and Eggers. The order-disorder transforn~ation of the y phase, postulated by Hellner, does not appear to exist. The liquidus is found to lie approximately 8 "C higher than that determined by Weibke and Eggers.At room temperature, the E phase exists between 67.5 and 65.0% silver. At these compositions, the cubic cell edges of the E phase are o = 9.878 + 0.004 and 9.887 0.004 A, respectively. The y/(y + E) phase boundary has been redetermined and extended.A new a' phase is claimed to exist at approximately 73.8 wt. % silver. It is formed by a peritectoid phase reaction at 187". In the a' phase the silver atoms occupy the face-centered positions and the indium atoms, the corner positions of the cubic lattice. The intensities of diffraction lines were calculated using such a model and were found to be in reasonable agreement with the observed intensities of the a' phase. The cell edge of the a' phase is 4.144 + 0.004 A, at room temperature, and this is identical, within experimental error, with that of the a phase.A new phase diagram for the Ag-In system has been constructed.

Thermodynamic and Experimental Study of the Mg-Sn-Ag-In Quaternary System

“…Each alloy was remelted three times in its crucible in order to obtain a homogeneous alloy; the melting loss was less than 5 wt.% for each sample. Mg-Sn-Ag samples were then sealed into quartz capsules under argon atmosphere and equilibrated at 415°C for 20 days and at 350°C for 35 [39,43,47,48] In / at.% Enthalpy of mixing, kJ·mol [50][51][52][53]57] respectively. These temperatures were chosen because they correspond to the temperatures at which heat treatment is usually performed on Mg alloys.…”

“…The u (AgIn 3 ) phase reported by Weibke and Eggers [39] was confirmed as AgIn 2 (with a CuAl 2 -type crystal structure) by Hellner. [42] Campbell and Wagemann [43] re-investigated the phase equilibra in the whole composition range of the Ag-In system by DTA, XRD, photomicrography and EPMA. The existence of the bcc phase was confirmed between 660 and 695°C and the hcp phase was found to decompose at 670°C following the peritectoid reaction fcc + bcc M hcp.…”

“…The homogeneity region of the e phase was reported to lie between 67 and 70 at.% Ag by Campbell and Wagemann. [43] Uemura and Satow [44] investigated the order-disorder transition of Ag 3 In by using specific heat capacity measurements, electrical resistivity, magnetic susceptibility and X-ray analysis. The orderdisorder transition of the hcp phase was observed to occur at 214°C.…”

A reaction study of sulfur vapor with silver and silver–indium solid solution as a tarnishing test method

“…The maximum solubility of indium element in silver crystal lattice is 20 at.% at room temperature, the silverindium solid phase with face-centered cubic (FCC) crystal structure is designated as a phase historically. In the literature [25], the authors discovered a' phase, which has also cubic crystal structure, at the composition of 25 at.%, and it is correspond to Ag 3 In which is transformed from f phase at 187°C. It is important to note that material composition may fluctuate from region to region, which can be caused by various mechanism of segregation effects.…”

The ternary system silver–indium–aluminum

“…2 and 4) does indicate that the o-phase is nearly pure aluminum. The &-phase has a composition range of 2% in the binary system Ag-In (3,8) and, since the 148 "C arrest line (peritectic) in vertical section I1 (Fig. 3) terminates at approximately 8 % Al, the solubility of aluminum in E can only be small, and the field of homogeneity of E in the ternary systemmust thereforebe smallat this temperature.…”