Platinum is fcc with a relatively high melting point, and good corrosion resistance in many aggressive environments. In the same group as nickel, it reacts similarly with other elements. Platinum’s higher melting point (1769°C) than nickel (1455°C) is advantageous. However, there are two serious disadvantages for platinum-based alloys in applications for moving parts: high densities and high costs. Partly due the improvements in recycling, the platinum price has decreased, and the densities can be slightly reduced by alloying with lighter metals.
Different platinum-based alloys were designed and tested. Most alloys had aluminium to produce the strengthening precipitates, as well as corrosion resistance. Density was reduced by substituting lower density but high melting point elements: vanadium and/or niobium. Ruthenium was added for corrosion resistance and solid solution strengthening. A thermodynamic database of Pt-Al-Cr-Ru was developed to optimize compositions, which were characterized and mechanically tested.