Modification of cupronickel alloy surface with octadecylphosphonic acid self–assembled films for improved corrosion resistance

•Protective films of octadecylphosponic acid were formed on CuNi alloy.•Modified CuNi surface was characterized by contact angle measurements, FTIR, SEM and electrochemical techniques.•Temperature of adsorption and drying significantly influenced obtained corrosion protection. The aim of this work was to form protective and durable films of octadecylphosphonic acid on the surface of CuNi alloy. In order to achieve this goal several parameters of the film preparation procedure were examined: temperature and duration of adsorption as well as the drying temperature. It was found that these parameters had significant impact on the corrosion protection efficiency and durability. The best corrosion protection was obtained when both adsorption and drying were conducted at elevated temperatures. The maximum protection efficiency was 96% for the first and 82% for the 14th day of exposure to corrosive medium.