The corrosion and electrochemical characteristics of zirconium at interaction it with molten carbonates of lithium. sodium, potassium at a temperature 500-800°C, containing from 1 to 5 weight percent additives in the salt phase, were studied. Gravimetric method, the corrosion potentials method and the method of anodic polarization curves were used. As corrosion passivators were used chemicals reducing corrosion losses by hardening and thickening of the oxide film (hydroxides of lithium, sodium, potassium). As corrosion stimulators (activators) were used chloride, fluoride and sulfate of sodium.