Patent ID: 7964541

Claim:
A lubricant composition for polishing a magnetic head with fixed abrasive grains, said lubricant composition comprising: (1) 100 parts by mass of a hydrocarbon solvent; (2) 0.001 to 4.999 parts by mass of an organic onium salt represented by the following formula (I): wherein Z is a nitrogen atom or a phosphorus atom, R 1 , R 2 , R 3 and R 4 are each independently a hydrocarbon group having 4 to 20 carbon atoms, with the proviso that the ratio of the number of carbon atoms of a hydrocarbon group having the largest number of carbon atoms to the number of carbon atoms of a hydrocarbon group having the smallest number of carbon atoms out of R 1 , R 2 , R 3 and R 4 is 2 or less, and X − is an anion represented by the following formula (II): A 1 -N − -A 2 (II) wherein A l and A 2 are each independently a fluoroacyl group, fluoroalkoxycarbonyl group, fluoroalkylsulfonyl group, fluoroalkoxysulfonyl group or nitrile group; and (3) 0.001 to 4.999 parts by mass of a fatty acid having 8 to 25 carbon atoms, the total amount of the organic onium salt and the fatty acid being 0.01 to 5 parts by mass.