[en] The coating of molybdenum on vanadium and vanadium alloy by the hydrogen reduction of molybdenum pentachloride has been investigated with the aim of improving the resistance of the vanadium substrate to sodium corrosion. Underlayer coating on the vanadium prior to the vapor-plating of molybdenum was found to be essential to secure good adhesion of the coating layer on vanadium. Coated specimens were examined by bend tests, thermal cycling tests, adherence tests, and sodium corrosion tests. An adherent and uniform molybdenum layer was formed on nickel-plated vanadium at a temperature above 750⁰C, and at the reaction pressures of 50 Torr, or lower, from the vapor mixture with a large excess of hydrogen. The molybdenum layer, obtained under favorable conditions, was found to protect the vanadium substrate from corrosion in liquid sodium containing about 1 ppm oxygen at 700⁰C. (Auth.)