Polishing formulations for SiO2-based substrates
a technology of sio2-based substrates and polishing formulations, applied in the field of abrasive particles, can solve the problems of high surface area, worse surface finishing than, and higher material removal ra
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
Problems solved by technology
Method used
Examples
example 1
[0016] A fumed silica powder with a surface area of 15 m.sup.2 / g, 300 g, which corresponds to an average particle size of about 300 nanometers, was dispersed in 2700 g of water. After 30 min. of sonication, 150 g of cerium nitrate hexahydrate is added which gives a solution at pH 2.7. The pH of the dispersion was adjusted using 500 g of urea and the mixture was aged at about 90.degree. C. for a period of 16 hours. During this time the pH changed from about 3.64 to 8.3. After the pH had stabilized at this level, the solid material was separated by centrifuge and dried in an oven for overnight before being fired at 800.degree. C. over a period of about 2 hours. The fumed silica powder showed a weight increase of 15% due to the formation of a ceria shell around the particles. After firing, this material is crushed and pulverized into powder to make a polishing slurry.
[0017] A number of glass polishing slurries were produced with a pH of 10 and a 5 wt % solids content of the abrasive. T...
example 2
[0024] The fumed silica used in Example 1, (200 g) was mixed with 1800 g of DI water. 2.12 g of ammonia was added to adjust the pH to 10 under vigorous stirring. In a separate beaker, 100 g of Ce(NO.sub.3).sub.3.6H.s-ub.2O was dissolved in 100 g of DI water. Under the vigorous stirring, the cerium nitrate solution is added drop wise to the fumed silica slurry slowly. At the same time, aqueous ammonia (.about.30%) is added to the slurry to keep the solution at pH .about.10 and thus ensure that all cerium salt hydrolyzes completely. In total, 86.8 g of ammonia was added together with the cerium nitrate solution. After finishing addition of the cerium nitrate solution, solid material is separated from solution by centrifuge and dried in oven for overnight. Thereafter, the material is fired at 800.degree. C. / 2 hrs, followed by crushing into fine powder before being mixed with water to make a polishing slurry.
example 3
[0025] The above procedures in Example 2 were used to generate the core-shell structure on fused silica powder which is commercially available from Alfa Aesar, with 2 um average particle size; S.A., 2 m.sup.2 / g; and 99.5% purity. The fused silica was first dispersed in water, with pH adjusted with ammonia. The slurry was poured through a metal screen #325 to remove any large particles, before the same treatment the same way as in Example 2. The product was pulverized into powder for polishing test.
PUM
| Property | Measurement | Unit |
|---|---|---|
| pH | aaaaa | aaaaa |
| temperature | aaaaa | aaaaa |
| temperature | aaaaa | aaaaa |
Abstract
Description
Claims
Application Information
Login to View More