Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter
Reexamination Certificate
2000-05-15
2001-11-20
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Particulate matter
C428S404000, C428S698000, C427S180000, C427S217000, C427S250000, C427S294000, C051S293000, C051S295000, C051S309000
Reexamination Certificate
active
06319608
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
None
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable
BACKGROUND OF THE INVENTION
The present invention relates to metal coated abrasive particles or grit and more particularly to such coated grit for improving its retention in saw blade segments.
Superabrasive grit, such as diamond particles, is widely used in sawing, drilling, dressing, grinding, lapping, polishing, and other abrading applications. For these applications, the grit typically is surrounded in a matrix of a metal, such as Ni, Cu, Fe, Co, Sn, W, Ti, or an alloy thereof, or of a resin, such as phenol formaldehyde or other thermosetting polymeric material. By attaching the matrices to a body or other support, tools may be fabricated having the capability to cut through such hard, abrasive materials as concrete, asphalt, masonry, ceramic, brick, or granite, marble, or other rock. Exemplary of such tools is a saw blade as disclosed in U.S. Pat. No. 4,883,500 to be comprised of a circular steel disk having a number of spaced segments disposed about its cutting edge. Each of the segments includes an amount of diamond grit dispersed in a suitable bonding matrix of a metal or alloy, such as Co, bronze, cemented metal carbide, or the like.
The retention of diamond grit within the matrix primarily involves a mechanical component developed from the surrounding of the individual particles by the matrix. The exposure of the grit, accordingly, must be limited so as not to critically weaken the mechanical properties of the surrounding matrix on the grit particles. For example, in a typical saw blade application, the average exposure of the grit is less than about 20% of the total grit height. The limited grit exposure, in turn, limits the cutting rate. Moreover, as the matrix is ablatively worn during the use, the service life of the tool may be shortened as up to two-thirds of the grit is prematurely lost by its being pulled or popped out of the surrounding matrix.
In an attempt to improve grit retention, it has been proposed to coat diamond particles with carbide-forming transition metals, such as Mo, Ti, and Cr. Such metals typically are chemically vapor deposited (CVD) or sputtered onto the surfaces of the diamond grit. Examples of such coatings and processes for the deposition thereof are disclosed in U.S. Pat. Nos. 3,465,916; 3,650,714; 3,879,901; 4,063,907; 4,378,975; 4,399,167; 4,738,689; in U.S. Reissue No. 34,133; and in EP-A79/300,337.7. It has been reported, however, that these coatings may be oxidized and, depending upon the carbide formed, may be brittle. In response, proposals have been made to use a carbide-forming metal layer as part of a multi-layer coating system. As is described in U.S. Pat. Nos. 3,929,432; 5,024,680; 5,062,865; and 5,232,469, systems generally involve the vapor-phase deposition of an inner layer of a thin, 0.05 to 15 micron thick carbide-forming metal, and an outer layer of a more corrosion resistant metal, such as Ni or Cu for protecting the inner layer from oxidation.
BRIEF SUMMARY OF THE INVENTION
Diamond particles are coated with a Ti metal to form Ti metal coated diamond particles product by contacting the diamond particles with an alloy of the following composition, Ti
(1−x)
Cr
x
, where x ranges from about 0.05 to about 0.5, at a temperature of less than about 850° C. and for a time sufficient for the alloy to coat the diamond particles. The resulting coated diamond particles have an average particle size ranging from about 5 to 800 &mgr;m and are coated with metal coating composed of an inner carbide layer enriched in Cr content and an outer layer depleted in Cr content. The total Cr content in the coating layer usually is no greater than about 10 wt-%.
REFERENCES:
patent: Re. 34133 (1992-11-01), Thorne
patent: 3465916 (1969-09-01), Hibbard et al.
patent: 3650714 (1972-03-01), Farkas
patent: 3879901 (1975-04-01), Caveney
patent: 3929432 (1975-12-01), Caveney
patent: 4063907 (1977-12-01), Lee et al.
patent: 4378975 (1983-04-01), Tomlinson et al.
patent: 4399167 (1983-08-01), Pipkin
patent: 4738689 (1988-04-01), Gigl
patent: 5024680 (1991-06-01), Chen et al.
patent: 5062865 (1991-11-01), Chen et al.
patent: 5232469 (1993-08-01), McEachron et al.
patent: A79/300337.7 (1979-09-01), None
Dey Nishit
Meng Yue
General Electric Company
Kiliman Leszek
Mueller and Smith LPA
LandOfFree
Titanium chromium alloy coated diamond crystals for use in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Titanium chromium alloy coated diamond crystals for use in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Titanium chromium alloy coated diamond crystals for use in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617997