The present invention relates to a cobalt-based alloy for the coating of organs subject to erosion by liquid comprising chromium 28-32% by weight, tungsten 6-8% by weight, silicon 0.1-2% by weight, carbon 1.2-1.7% by weight, nickel 3-6% by weight, molybdenum 1-3%, cobalt the complement to 100%. The invention also relates to an application method of the alloy on organs subject to erosion by liquid, in particular vapour turbine blades, to reduce the metal erosion rate following impact with liquids.