Mixed rare earth oxide, mixed rare earth fluoride, cerium-based abrasive using the materials and production processes thereof

Abstract

The present invention provides a mixed rare earth oxide for the production of a cerium-based abrasive, in which the ignition loss after heating at a temperature of 1,000 DEG C for 1 hour is 0.5 mass% or less on the dry mass basis and the crystallite diameter is from 200 to 400 A; a mixed rare earth fluoride for the production of a cerium-based abrasive, in which the ignition loss is from 3 to 15% on the dry mass basis; a process for producing a cerium-based abrasive from these mixed rare earth oxide or mixed rare earth fluoride; and a cerium-based abrasive produced by using these mixed rare earth oxide or mixed rare earth fluoride.

Description

[0001] Cross References to Related Applications [0002] This application is an application filed pursuant to 35 U.S.C. 111 §(a), pursuant to 35 U.S.C. 119 §(e) requiring provisional application 60 / 608,877 filed September 13, 2004 under 35 U.S.C. 111 §(b) Benefits on filing date. field of invention [0003] The present invention relates to a cerium-based abrasive for polishing transparent substrates, such as glass substrates for optical lenses, liquid crystal panels, hard disks, specific frequency wavelength filters, etc.; raw materials for abrasives; and methods of making them. In particular, the present invention relates to cerium-based abrasives for final polishing of high-precision glass substrates (such as hard disk substrates) and glass substrates for liquid crystal panels; raw materials for said abrasives; and methods for their preparation . Background technique [0004] More recently, glass materials have been used extensively, and in some of these applications su...

AI Technical Summary

Problems solved by technology

[0009] However, when conventional cerium-based abrasives are used under conventional polishing conditions, the processing rate is low, but there are problems in that: the polishing rate drops sharply due to the clogging of the polishing pad; the dressing of the polishing pad or the exchange of the polishing slurry must be frequently performed ; and productivity has seriously deteriorated

However, in processes using this raw material, carbonic acid is lost as a gas during final combustion in the process of producing cerium-based abrasives

Therefore, this method cannot ensure low material cost and high combustion efficiency

In addition, if the degree of combustion of the framework rare earth oxide is low, the finally obtained cerium-based abrasive grains become uneven in hardness, which causes problems such as scratches on polished glass surfaces or very short polishing rates. decrease in time

In particular, in the case of hard glass surfaces, a sharp decrease in polishing rate is fatal