First-principles thermal compatibility between Ru-based Re-substitute alloys and Ir coatings

We perform first-principles calculations to assess the thermal compatibility between Ru-based base alloys and Ir coatings. We use special quasirandom structures for atomistic modeling of disordered Ru7X, Ru6XX′, and Ru3X alloys, where X,X′∈Mo,Ta,W, and the quasiharmonic approximation to obtain thermal expansion coefficients up to 2400 K. Most of the proposed Ru-based alloys show better thermal compatibility with Ir than Re. A four-dimensional thermal expansion model of the Ru–Mo–Ta–W quaternary system is presented.