A composition and associated method for chemical mechanical planarization (or other polishing) are described. The composition contains a ketoxime compound and water. The composition may also contain an abrasive and/or a per compound oxidizing agent. The composition affords tunability of removal rates for metal, barrier material, and dielectric layer materials in metal CMP. The composition is particularly useful in conjunction with the associated method for metal CMP applications (e.g., step 2 copper CMP processes).