3.3.2. Ruthenium
The Ru–W–S ternary phase diagram in Fig. 5c was drawn relying on the corresponding binary phase diagrams from No intermetallic phase was found in the Ru–W system, but the solid solubility of W in Ru is very high regardless of the crystal structural differences between hexagonally close-packed Ru and body-centered cubic W. We incorporated 40 at.% W solubility in Ru (solubility at 1773 K ) into our calculation as discussed in Section 2.2. The resulting phase diagram at 298 K was WS2 dominant, as shown in Fig. 5c. However, considering the inclusion of solubility did not alter any of the phases in equilibrium with each other, we decided not to depict this solubility for any of the other systems with significant solubility for simplification. A simplified Ru–W–S ternary phase diagram is shown in Fig. 5d, which is the style we adopt in the rest of the paper.