Abrasive particles for surface polishing

Details Abrasive particles for surface polishing Abrasive particles for surface polishing

1997-10-31

2001-09-18

Koslow, C. Melissa (Department: 1755)

Abrasive tool making process, material, or composition

With inorganic material

Reexamination Certificate

active

06290735

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to abrasive compositions useful for surface polishing, especially mechanochemical polishing, and methods for producing abrasive particles.
BACKGROUND OF THE INVENTION
Technological advances have raised the demand for improved material processing with strict tolerances on processing parameters. In particular, smooth surfaces are required in a variety of applications in electronics, tool production and many other industries. The substrates requiring polishing can involve hard materials such as ceramics, glass and metal. As miniaturization continues even further, even more precise polishing will be required. Current submicron technology requires polishing accuracy on a nanometer scale. Precise polishing technology can employ mechanochemical polishing involving a polishing composition that acts by way of a chemical interaction of the substrate with the polishing agents as well as an abrasive effective for mechanical smoothing of the surface.
SUMMARY OF THE INVENTION
Improved polishing compositions are described for smoothing surfaces to very low tolerances. The polishing compositions are based on small particles with a very narrow distribution of particle diameters to provide for more control over the polishing process. Furthermore, a collection of preferred particles have effectively no particles with significantly larger diameters. In addition, the preferred particles have a very high level of purity with respect to a single crystalline phase. Laser pyrolysis provides for the production of preferred particles. Laser pyrolysis not only provides for the production of particles with preferred properties for abrasive applications but also for efficient and controlled production of the particles. These features provide for cost effective commercialization of the improved abrasive compositions.
In a first aspect, the invention features a composition comprising a dispersion of particles, the particles including metal compounds and having an average particle diameter from about 5 nm to about 200 nm and a distribution of diameters such that at least about 95 percent of the particles have a diameter greater than about 60 percent of the average diameter and less than about 140 percent of the average diameter. The particles can be dispersed in an aqueous or nonaqueous solution. The particles preferably comprise a composition selected from the group consisting of SiO
2
, SiC, TiO
2
, Fe
3
C, Fe
7
C
3
, Fe
2
O
3
, Fe
3
O
4
, MoS
2
, MoO
2
, WC, WO
3
and WS
2
. The particles preferably have an average diameter less than about 100 nm.
In another aspect, the invention features a composition comprising a dispersion of particles, the particles including metal compounds with an average particle diameter from about 5 nm to about 200 nm and a single crystalline phase with a uniformity of at least about 90 percent by weight. The particles can be dispersed in an aqueous or nonaqueous solution. The particles preferably have a single phase uniformity of at least about 95 percent by weight, more preferably at least about 99 percent by weight and even more preferably at least about 99.9 percent by weight.
In another aspect, the invention features a composition comprising a dispersion of particles, the particles including metal carbides or metal sulfides and having an average particle diameter from about 5 nm to about 200 nm.
In another aspect, the invention features a method of smoothing a surface comprising the step of polishing the surface with a composition of the invention, as summarized above and further described below. The polishing can be performed with a polishing pad and can involve a motorized polisher.
In another aspect, the invention features a method of producing SiO
2
particles including the step of pyrolyzing a molecular stream comprising a silicon compound precursor, an oxidizing agent and a radiation absorbing gas in a reaction chamber, where the pyrolysis is driven by heat absorbed from a laser beam. The silicon compound precursor can include a compound that is selected from the group consisting of CH
3
SiCl
3
. The laser beam preferably is supplied by a CO
2
laser. The molecular stream preferably is generated by a nozzle elongated in one dimension.
In another aspect, the invention features a method of producing iron oxide particles comprising the step of pyrolyzing a molecular stream comprising a iron compound precursor, an oxidizing agent and a radiation absorbing gas in a reaction chamber, where the pyrolysis is driven by heat absorbed from a laser beam. The iron precursor can comprise Fe(CO)
5
.
Other features and advantages are evident from the detailed description of the invention and claims presented below.


REFERENCES:
patent: 4011099 (1977-03-01), Gutsche
patent: 4021263 (1977-05-01), Rosenblum
patent: 4356107 (1982-10-01), Payne
patent: 4659681 (1987-04-01), Rice et al.
patent: 4668647 (1987-05-01), Rice et al.
patent: 4687753 (1987-08-01), Fiato et al.
patent: 4690693 (1987-09-01), Dobbs et al.
patent: 4788222 (1988-11-01), Rice et al.
patent: 4842837 (1989-06-01), Shimizu et al.
patent: 4910155 (1990-03-01), Cote et al.
patent: 4956313 (1990-09-01), Cote et al.
patent: 5006318 (1991-04-01), Demazeau et al.
patent: 5013706 (1991-05-01), Schramm et al.
patent: 5064517 (1991-11-01), Shimo
patent: 5128081 (1992-07-01), Siegel et al.
patent: 5228886 (1993-07-01), Zipperian
patent: 5300130 (1994-04-01), Rostoker
patent: 5318927 (1994-06-01), Sandhu et al.
patent: 5320800 (1994-06-01), Siegel et al.
patent: 5352277 (1994-10-01), Sasaki
patent: 5389194 (1995-02-01), Rostoker et al.
patent: 5456986 (1995-10-01), Majetich et al.
patent: 5527423 (1996-06-01), Neville et al.
patent: 5547649 (1996-08-01), Beck et al.
patent: 5549973 (1996-08-01), Majetich et al.
patent: 5626715 (1997-05-01), Rostoker
patent: 0 209 298 (1987-01-01), None
patent: 554908 (1993-08-01), None
patent: 0 554 908 (1993-08-01), None
patent: 0 776 862 (1997-06-01), None
patent: 2275629 (1990-11-01), None
patent: WO 96/41043 (1996-12-01), None
Bi et al, “Nanocrystalline alpha-Fe, Fe3C, and Fe7C3 produced by CO2 laser pyrolysis”, J. Mater. Res., vol. 8, No7, Jul. 1993.*
Ford, “ManufactureNanocrystalline Materials by Physical Vapor Synthesis”.*
“Continuous Production of &ggr;-Fe2O3Ultrafine Powders by Laser Pyrolysis” by, Veintemillas-Verdaguer et al., Materials Letters 35, 1998, pp. 227-231.
“Iron-Oxide-Based Nanoparticles Produced by Pulsed Infrared Laser Pyrolysis of Fe(CO)5” by, Alexandrescu et al., Materials Chemistry and Physics 55 (1998) pp. 115-121.
“Nanocrystalline &agr;-Fe, Fe3C, and Fe7C3produced by CO2laser pyrolysis” by, Bi et al., J. Mater. Res., vol. 8, No. 7, Jul. 1993, pp. 1666-1674.
“Preparation of &ggr;-Iron Ultrafine Particles Using a Transversely Excited Atmospheric CO2Laser” by, Majima et al., Jpn. J. Appl. Phys. vol. 33, Part 2, No. 2B, Feb. 15, 1994, pp. L223-L226.
“Sinterable Ceramic Powders from Laser-Driven Reactions: II Powder Characteristics and Process Variables” by, Cannon et al., Journal of the American Ceramic Society, vol. 65, No. 7, Jul. 1982, pp. 330-335.

Affiliated with

Also associated with

Rating

Abrasive particles for surface polishing does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Abrasive particles for surface polishing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Abrasive particles for surface polishing will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2498029