| 摘要 |
A composition containing silica sol is provided which comprises:
a colloidal silica particle group having a monomodal numerical particle size distribution with primary particle sizes of 40 to 70 nm as observed on a transmission electron microscope being 90% or more of the total particle number, and having a mean particle size D b (particle size measured with the nitrogen adsorption method) in the range of 35 to 50 nm (referred as colloidal silica particle group (b) hereinafter), and
a colloidal silica particle group having a monomodal numerical particle size distribution with primary particle sizes of 20 to 40 nm as observed on a transmission electron microscope being 90% or more of the total particle number, and having a mean particle size D c (particle size measured with the nitrogen adsorption method) in the range of 15 to 25 nm (referred as colloidal silica particle group (c) hereinafter) or
a colloidal silica particle group having a monomodal numerical particle size distribution with primary particle sizes of 5 to 15 nm as observed on a transmission electron microscope being 90% or more of the total particle number, and having a mean particle size D d (particle size measured with the nitrogen adsorption method) in the range of 8 to 12 nm (referred as colloidal silica particle group (d) hereinafter,
wherein said composition has a ratio of D c /D b of 0.30 to 0.71 or the ratio of D d /D b of 0.16 to 0.34, is a water dispersed stable silica sol mixed with SiO 2 with the weight ratio of said colloidal silica particle group (c) or said colloidal silica particle group (d) and said colloidal particle group (b) being W(b)/[W(c) or W(d)] = 1/0.05 to 9.0, and contains colloidal silica particles with the SiO 2 concentration of 0.5 to 50% by weight. The composition is suitable as a polishing composition for an aluminium disk or a polishing composition for a substrate with silica on the surface. |
