Results are presented from a study of the superconducting properties of molybdenum carbide synthesized in the surface layer of bulk molybdenum using an original technology: ion-plasma bombardment of metallic molybdenum with carbon and silicon ions to implant carbon in the surface layer of the molybdenum. The temperature evolution of the superconducting resistive transition of samples with a carbidized surface is studied as a function of the thickness and continuity of the carbide layer. A generalization of the parameters of the superconducting transition for all the samples indicates that the carbide layers produced by this technology have a mosaic-island structure and a nonuniform superconductivity associated with this structure. The main contribution to the smearing out of the superconducting transition under these conditions may come from pulling of the potential at the N-S boundaries between normal molybdenum and carbide clusters.