Phase Diagram of the Nickel–Platinum System

The phase diagram of the nickel–platinum system was constructed with extrapolation of phase equilibria to absolute zero temperature according to the requirements of the third law of thermodynamics. An fcc continuous solid solution crystallizing from the melt undergoes ordering with separation into three intermetallic phases (Kurnakov phases), whose homogeneity regions with decreasing temperature tend to stoichiometric compositions Ni 3 Pt, NiPt, and NiPt 3 . With increasing temperature, platinum and nickel occupy some of the crystallographic positions of the second component in the intermetallic phases. In the solid state, in the system, there are two eutectoids with the coordinates (500°C, 36 at % Pt) and (480°C, 64 at % Pt) and three dystectoids with the coordinates (515°C, 31 at % Pt), (645°C, 50 at %Pt), and (510°C, 72 at % Pt).