Molybdenum–rhenium (Mo/Re) alloys were investigated as substrates for thin-film, polycrystalline boron-doped diamond electrodes. Boron-doped semimetallic diamond was deposited on Mo-Re (42.5/57.5 wt. %) substrates by hot filament chemical vapor deposition method with a periodic magnetic field (PMF). Cyclic voltammograms showed the wide window and low baseline current of high-quality boron doped diamond electrodes. Overall, the Mo/Re alloys were suitable substrates for diamond growth. PMF may have a great practical application potential in diamond growth by chemical vapor deposition.