Abstract: A chemical mechanical polishing composition for polishing a substrate having a cobalt layer includes a water based liquid carrier, cationic silica abrasive particles dispersed in the liquid carrier, and a triazole compound, wherein the polishing composition has a pH of greater than about 6 and the cationic silica abrasive particles have a zeta potential of at least 10 mV. The triazole compound is not benzotriazole or a benzotriazole compound. A method for chemical mechanical polishing a substrate including a cobalt layer includes contacting the substrate with the above described polishing composition, moving the polishing composition relative to the substrate, and abrading the substrate to remove a portion of the cobalt layer from the substrate and thereby polish the substrate.