In addition, the processing of such coated diamonds, whether or not PCD components or natural, in an oxidizing atmosphere is not practical because any imperfection or dissolution of the outer nickel or copper coating, for example, by the motion of the liquid binder, would outcome within the oxidation and destruction of the underlying titanium and titanium carbide layer. Since subsequent processing in an oxidizing environment would result in the formation of an oxide that isn’t simply wetted by different materials, the covered herbal diamond particles are overcoated with either nickel or copper with a movie thickness of between 0.002 and zero.0.5 of an inch between 50.Eight and 127 microns thick. It is also recognized in the sintering of synthetic diamond to use a skinny coating of between three hundred and six 000 angstroms of a robust carbide former, with a second coating of copper with subsequent processing at 5 Kbar at a temperature of 600 to 700 degrees C. in an inert environment, see the U.S.
The coated diamond grit is formed into numerous shapes by drilling tools a hot, urgent procedure or infiltration at an elevated temperature. An essential issue with the above procedure and the resulting product is that the carbide-containing coating is sort of thin, substantially lower than one micron, with the result that below certain kinds of subsequent processing comparable to with the use of liquid binders in infiltration, as in the formation of an infiltrated matrix for earth uninteresting bits, the liquid binder penetrates the protecting coating and the comparatively skinny carbide containing coating. Thin coatings equivalent to those described in Farkas would contain substantial imperfections and voids that may permit the liquid infiltrating binder to assault the carbide interface between the pad and the coating and separate the coating from the PCD.
This outer coating is said to serve as a protecting coating to stop oxidation of the titanium or zirconium or their carbides throughout subsequent processing beneath oxidizing situations. No. 3,879,901 describes the vacuum deposition of steel such as molybdenum or titanium on diamond substances with subsequent processing at 60 Kbar and between 1,200 and 1 and four hundred degrees C. to kind a diamond product. The green physique is then sintered at 950 levels C. with a diamond volume of between 10% and 40% by volume. The processed tungsten powder is then balled and milled for about 24 hours using tungsten rods because the milling media is sieved and screened to 200 mesh seventy-four microns. Pat. Nos. 3,871,840 and 3,841,852. The products there described are about 25% by the quantity of diamond grit of particle dimension from forty to 100 mesh and represent an improved impregnated product compared to an improved giant diamond product.
