The Rh-Ru (rhodium-ruthenium) system

The assessed Rh-Ru equilibrium diagram shown in Figure 1 is based primarily on the results of [83Pas] and [84Pas], who investigated the system in the temperature range from 900-2300 deg C using differential thermal analysis (DTA), x-ray diffraction (XRD), electron probe microanalysis (EPMA), metallography, and microhardness examinations of six quenched samples over the composition span of 25-75 at.% Ru. No data are available for the liquidus. Hence the liquidus is shown by a dashed curve in Figure 1. In addition, there are only two more experimental reports, [54Hal] and [73Sav], on the system. [54Hal] reported the changes in the lattice parameters of Ru on the addition of Rh, and [73Sav] reported the Rh-Ru system to be a simple peritectic type. [70Kau] reported a phase diagram calculated on the basis of a regular solution model and predicted it to be eutectic with a eutectic temperature of approx1830 deg C. The equilibrium phases in the Rh-Ru system are the liquid, L, and the two terminal solid solutions, the hexagonal (Ru) phase with dissolved Rh and the face centered cubic (fcc) (Rh) phase with dissolved Ru. No intermetallic phases are reported.