A diamond abrasive article preferably in the form of a grinding wheel, the work-contacting portion of which has a resinoid body containing metal coated diamond particles and also containing powdered metal of two kinds, one of the powdered metals having a relatively low melting point and the other having a substantially higher melting point, such as tin and copper, respectively.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 337,876, filed in the UNITED STATES PATENT OFFICE Mar. 5, 1973 and now abandoned.
Multiple metal coated diamond grit for improved retention in a tool matrix comprises a first layer coating of a metal carbide of a strong carbide former, preferably chromium, titanium or zirconium, chemically bonded to the diamond and a second metal coating of an oxidation resistant carbide former, preferably tungsten or tantalum, chemically bonded to the first metal layer. A third metal layer coating of an alloying metal, preferably nickel, can also be added. In accordance with the method of the present invention, the first layer metal can be applied by metal vapor deposition. The second layer metal can be applied by chemical vapor deposition. The third layer of an alloying metal can be applied by electroless or electrolytic plating.
Disclosed is an improved polycrystalline compact of self-bonded diamond particles having a network of interconnected empty pores dispersed throughout. The improved porous polycrystalline diamond compact possesses enhanced oxidation resistance and comprises all of the exterior surfaces of the porous compact being enveloped with a continuous coating which is effective under metal bond fabrication conditions so that oxidation of the diamond in the compact does not exceed a threshold level whereat loss of diamond properties of the compact occurs. Metal bond fabrication conditions comprehend an atmosphere containing oxygen or water vapor. Metal coatings are preferred, especially in coating thicknesses in excess of about 8 microns, and applied by a chemical vapor deposition process.
A vitreous bonded abrasive tool comprises 12 to 50% bond, 5 to 50% metal coated superabrasive, at least 10% porosity and 2 to 20% solid lubricant. The abrasive tool containing titanium or nickel coated diamond is particularly effective in grinding ceramic material, such as sapphire.
Co-molded articles such as abrasive grinding wheel structures having a polyimide resin-bonded phase and a metal-bonded phase are provided. A process also is provided for co-molding such structures by the simultaneous application of heat and pressure to an abrasive-containing rim of polyimide resin and a core of metal powder.
Disclosed is an improvement in method for both dry grinding and wet grinding a workpiece selected from cemented tungsten carbide and combinations of cemented tungsten carbide and steel with a single resin bonded grinding element having metal-coated diamond particles embedded in the grinding surface thereof. Such improved method comprises providing coated diamond particles useful for both dry grinding and wet grinding operations which comprises diamond coated particles coated with two layers of metal, the inner layer consisting of between about 40% and 130% by weight of said diamond particle of nickel and the outer layer consisting of between about 20% and 70% by weight of said diamond particle of silver, wherein the total weight of both said silver and nickel coatings does not exceed above about 200% by weight of the uncoated diamond particle.
