General Electric Company

Robert C De Vries

Minyoung Lee

Lawrence E Szala

Francis P Bundy

Robert H Wentorf, Jr

Extensive development of deformation bands in diamond crystals results from subjecting diamond material properly confined to reduce or eliminate brittle fracture thereof to the simultaneous application of high pressure and temperature in a defined region on the carbon phase diagram, the pressures and temperatures being incapable of bringing about significant crystal-to-crystal bonding of diamond. Plastic deformation resulting in work-hardening of these diamonds can be made to occur at temperatures as low as 900.degree. C. at pressures of about 60 kb. A work-hardened diamond for use in a single-point diamond tool would, for example, be prepared by embedding the diamond in diamond powder to fill the volume thereby inhibiting brittle fracture of the diamond being work-hardened.

Method for the work-hardening of diamonds and product thereof

A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy and a silicon nitride ceramic substrate are disposed in a container and placed within a pressure transmitting powder medium. Pressure is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents sufficient to dimensionally stabilize the container and its contents. The resulting shaped substantially isostatic system of powder-enveloped container is hot-pressed whereby fluid eutectiferous silicon-rich alloy is produced and infiltrated through the interstices between the diamond crystals and contacts the contacting face of the silicon nitride substrate sufficiently producing, upon cooling, an adherently bonded integral composite.

Process for preparing a polycrystalline diamond body/silicon nitride

A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy and a silicon carbide ceramic substrate are disposed in a container and placed within a pressure transmitting powder medium. Pressure is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents sufficient to dimensionally stabilize the container and its contents. The resulting shaped substantially isostatic system of powder-enveloped container is hot-pressed whereby fluid eutectiferous silicon-rich alloy is produced and infiltrated through the interstices between the diamond crystals and contacts the contacting face of the silicon carbide substrate sufficiently producing, upon cooling, an adherently bonded integral composite.

Process for preparing a polycrystalline diamond body/silicon carbide

A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy are disposed in a container and placed within a pressure transmitting powder medium. Pressure is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents sufficient to dimensionally stabilize the container and its contents. The resulting shaped substantially isostatic system of powder-enveloped container is hot-pressed whereby fluid eutectiferous silicon-rich alloy is produced and infiltrated through the interstices between the diamond crystals producing, upon cooling, an adherently bonded integral body.

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Burnt Hills, NY, United States of America

Robert C De Vries