PURPOSE: To form the surface of a substrate of a magnetic disk into the polished surface of uniform and fine roughness by specifying the volumetric mixing ratio of coarse grains and fine grains where the ratio of the grain size at the top of the on- sifter mass distribution and the mass frequency distribution is below the prescribed value.
CONSTITUTION: In the grain size distribution of abrasive grains, the monocrystal diamond abrasive grains having the grain size distribution where the ratio of the grain size (D90 diameter) whose on-sifter mass distribution is 90% to the grain size (MODE diameter) at the top of the mass frequency distribution is not greater than 1.7 are coarse within the range where the grain size (D50 diameter) whose on-sifter mass distribution is 50% is 0.5 to 10μm. The monocrystal diamond abrasive grains having the grain size distribution where the grain size (D50 diameter) whose on-sifter mass distribution is 50% is in the range of 0.1 to 0.9 times the grain size (D50 diameter) whose on-sifter mass distribution of coarse grains, and its maximum grain size does not exceed the maximum grain size of coarse grains are fine. The texture working is executed on the surface of a magnetic disk substrate 1 using abrasive grains where the volumetric mixing ratio of coarse grains to fine grains is in the range of 95:5 to 40:60.
HASHIMOTO TAKAYUKI
NAKAMURA HIROYUKI
ITO YOSHIAKI
