The invention provides a chemical-mechanical polishing composition containing aluminate-modified silica particles, a polyacrylamide, a heterocyclic film-forming agent, and water. The invention also provides a method of chemically-mechanically polishing a substrate, especially a nickel-phosphorous substrate, by contacting a substrate with a polishing pad and the chemical-mechanical polishing composition, moving the polishing pad and the polishing composition relative to the substrate, and abrading at least a portion of the substrate to polish the substrate.