The Co-Cr-Si (Cobalt-Chromium-Silicon) System

The cobalt-chromium-silicon (Co-Cr-Si) system has been investigated. The Cr-Si system has four intermediate phases, which includes Cr 3Si (β), (γ), Cr 5Si 3, CrSi (ζ), and CrSi 2 (δ), of which the β and βCr 5Si 3 (λ 1), and δ phases melt congruently at 1770, 1680, and 1490 °C, respectively. Two binary Co-Si alloys with 20 at.% Si and 80 at.% Si were arc melted under argon using electrolytic 99.9 mass% purity Cr, and 99.99 mass% purity Co, and 99.99 mass% purity Si. Alloys were annealed in evacuated and sealed quartz capsules for 100 h at 1150 °C. The three isothermal sections of the Co-Cr-Si system between 800 and 1150 °C show continuous solid solution region ζ between the CoSi and CrSi phases. The existence of the pseudobinary divide the Co-Cr-Si system into two parts, one with Si content <50 at.% and the other with Si content >50 at.%.