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Cerium-based abrasive, abrasive slurry, and production of cerium-based abrasive

a technology of cerium-based abrasives and slurry, which is applied in the direction of cellulosic plastic layered products, lapping machines, other chemical processes, etc., can solve the problems of high agglomerating force in a dry state, occurrence of fine scratches, and occurrence of scratches, so as to prevent the sintering of abrasive particles, eliminate the drop of these components during use, and easy and evenly coated

Inactive Publication Date: 2005-09-15
MITSUI MINING & SMELTING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention relates to a cerium-based abrasive with improved polishing properties. The inventors have reviewed and analyzed the causes of scratches during polishing and have come up with a solution to prevent these scratches. The solution involves coating the surface of the abrasive particles with a silicon or aluminum component to reduce agglomerating force and improve dispersibility. The coating layer should be strong enough to withstand the polishing process and should not easily desorb from the surface of the particles. The cerium-based abrasive with this coating has excellent polishing properties and does not cause scratches. The coating can be applied to the abrasive particles before or after roasting.

Problems solved by technology

The existence of the coarse particles is supposedly mainly attributed to abnormal particle growth of the small abrasive particles during a roasting step among the production steps of the abrasive particles and in addition to that, the existence is also supposedly attributed to the fact that particles with high agglomerating force in a dry state are insufficiently dispersed when the dry particle powder is made to be an abrasive slurry after production and consequently forming coarse particles in the slurry.
On the other hand, the cause of the occurrence of the fine scratches is supposedly related to the relation between the abrasive particles and an object to be polished.
The abrasive particles to which fine particles of the object are adsorbed abnormally agglomerate and the resulting agglomerates abrade the object again, resulting in the occurrence of the scratches.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0041] A bastnasite-based cerium oxide raw material was used and loaded together with water into an attriter (manufactured by Mitsui Mining Co., Ltd.) and pulverized to have the average particle diameter of 0.3 μm by a particle diameter measurement method which will be described later. After the slurry was transported to a receiving tank equipped with a stirring apparatus from the attriter, an aqueous sodium silicate solution measured so as to contain silicon in 1% by weight in relation to the cerium oxide weight was added while being stirred. After the resulting slurry was stirred for 5 minutes after addition, the pH was adjusted to be 8 by a diluted sulfuric acid and controlled to keep the pH for 30 minutes. The obtained slurry was filtered, dried, roasted at 950° C. and pulverized and then the particles with a particle diameter of 10 μm or larger were removed to obtain a powder of the cerium-based abrasive particles. The quantity of the silicon component coating on the surface of...

second embodiment

[0050] In this embodiment, a cerium-based abrasive coated with aluminum in place of silicon in the first embodiment was produced. After the bastnasite-based cerium oxide raw material was pulverized to have the average particle diameter of 0.3 μm in the same manner as the first embodiment, an aqueous aluminum sulfate solution measured so as to contain aluminum in 1% by weight in relation to the cerium oxide weight was added to the produced slurry while being stirred. After the resulting slurry was stirred for 5 minutes after addition, the pH was adjusted to be 6 by an aqueous NaOH solution and controlled to keep the pH for 30 minutes. The obtained slurry was filtered, dried, roasted at 950° C. and pulverized and then the particles with a particle diameter of 10 μm or larger were removed to obtain a powder of the cerium-based abrasive particles. The obtained powder of the cerium-based abrasive particles was evaluated in the same manner as the first embodiment and the obtained results ...

third embodiment

[0051] In this embodiment, a cerium-based abrasive coated with both silicon and aluminum was produced. After the bastnasite-based cerium oxide raw material was pulverized to have the average particle diameter of 0.3 μm in the same manner as the first embodiment, an aqueous sodium silicate solution measured as to contain silicon in 0.3% by weight in relation to the cerium oxide weight and an aqueous sodium aluminate solution measured so as to contain aluminum in 0.3% by weight were added to the produced slurry while being stirred. After the resulting slurry was stirred for 5 minutes after addition, the pH was adjusted to be 6 by a diluted sulfuric acid and controlled to keep the pH for 30 minutes. The obtained slurry was filtered, dried, roasted at 950° C. and pulverized and then the particles with a particle diameter of 10 μm or larger were removed to obtain a powder of the cerium-based abrasive particles. The obtained powder of the cerium-based abrasive particles was evaluated in t...

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Abstract

There is provided a cerium-based abrasive containing cerium oxide as a main component, in which the abrasive particles composing the abrasive are coated with a coating layer containing at least either one of a silicon component of silicon or a silicon compound and an aluminum component of aluminum or an aluminum compound. The cerium-based abrasive can be produced by wet-dispersing the cerium-based abrasive in a dispersion medium to obtain a slurry and carrying out surface treatment by adding a treatment solution containing at least either one of the silicon compound and the aluminum compound to the slurry. Further, the cerium-based abrasive can be produced by carrying out surface treatment by adding a treatment solution containing at least either one of the silicon compound and the aluminum compound to the slurry during the pulverization step or after the pulverization step in the conventional cerium-based abrasive production process and after that roasting and classifying the obtained cerium-based abrasive.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a cerium-based abrasive. More particularly, the invention relates to a cerium-based abrasive with high fluidity and dispersibility and excellent in polishing properties. BACKGROUND OF THE ART [0002] The range of the use of a cerium-based abrasive containing cerium-based particles as a main component has rapidly been increasing owing to the excellent polishing effects and the functions of a variety of additives added to the abrasive. Today, it is employed not only for a conventional purpose of polishing optical glass but for the fields of polishing glass for a liquid crystal, glass for a magnetic recording medium such as hard disks, and fabricating an electronic circuit such as LSI. [0003] The cerium-based abrasive has generally been produced by the following method. That is, raw materials are made to be a slurry, wet-pulverized, treated with a mineral acid as required, and then subjected to chemical treatment with hydrof...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B24B37/00C09C1/68C09G1/02C09K3/14H01L21/304
CPCC03C19/00C09G1/02C09K3/1436Y10T428/256C09K3/1463Y10T428/2993Y10T428/2991C09K3/1445C09K3/14
Inventor ITO, TERUNORIMOCHIZUKI, NAOYOSHIUSHIYAMA, KAZUYAWATANABE, HIROYUKI
Owner MITSUI MINING & SMELTING CO LTD