The present invention concerns a method for obtaining a finished or semi-finished zirconia-based article, the surface of the article having a metallic external appearance and non-zero surface electrical conductivity, wherein the method includes the steps of: taking at least one zirconia article, pre-shaped in its finished or semi-finished form; placing said article in a chamber in which a hydrogen and carbon/nitrogen gas mixture is heated; heating said article and the gas mixture using at least one resistive element traversed by an electric current to obtain dissociation of the hydrogen and carbon/nitrogen based gas molecules and an increase in the temperature of said article; keeping said article in the reactive atmosphere thus created to obtain diffusion of the carbon/nitrogen atoms in the external surface of said article.