| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an abrasive excellent in grinding force and high smoothness, stabilized in quality in a step of polishing a glass substrate for hard disks and comprising cerium oxide abrasive grains. SOLUTION: This abrasive comprising abrasive grains composed of a high- purity cerium oxide having >=95% purity of the content of the cerium oxide based on the content of all the rare earth oxides is used. The respective contents of uranium and thorium in the abrasive grains are <=0.01 mass %. The fluorine content in the abrasive grains is <=1 mass %. The abrasive is suspended in an aqueous medium and used in a slurry state.</p> |
