Coated diamonds for use in impregnated diamond bits

Abstract

An insert for an impreg bit that includes coated diamond particles disposed in a matrix material, wherein the coated diamond particles include a boride, a nitride, and a carbide of a group IVA, VA, VI transition metal or silicon disposed on synthetic, natural, TSP diamonds, or combinations thereof is disclosed. A method of forming a diamond-impregnated insert, including coating a plurality of diamond particles with a coating formed from a boride, a nitride, and a carbide of a group IVA, VA, VI transition metal or silicon or mixtures thereof, and forming a diamond impregnated insert body is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119 to U.S. Provisional Application Ser. No. 60 / 498,543, filed Aug. 28, 2003. This provisional application is hereby incorporated by reference in its entirety.BACKGROUND OF INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to drill bits used in the oil and gas industry and more particularly, to drill bits having diamond-impregnated cutting surfaces. Still more particularly, the present invention relates to drag bits in which the diamond particles imbedded in the cutting surface have a coating to improve diamond bonding and / or reduce diamond degradation. [0004] 2. Background Art [0005] In the drilling industry, it is well known that different types of bits work more efficiently with different formations. Rotary drill bits with no moving elements on them, referred to as “drag” bits, may be used to drill very hard or soft formations depending on the t...

AI Technical Summary

Benefits of technology

The present invention is about a new type of insert for drilling that includes coated diamond particles. These particles are coated with a material like boride, nitride, or carbide of a group IVA, VA, or VI transition metal. The coated diamond particles are then embedded in a matrix material, which is then infiltrated with a binder alloy. The result is a drill bit with improved performance. The invention also includes a method for making the diamond-impregnated insert. The technical effect of this invention is to provide a drill bit with better performance and durability.

Problems solved by technology

It has been found, however, that the life of both natural and synthetic diamond is shortened by the lifetime thermal exposure experienced in the furnace during the infiltration process.

For example, diamonds imbedded according to methods disclosed in the '202 patent have a total thermal exposure of less than 40 minutes, and more typically less than 20 minutes (and more generally about 5 minutes), above 1500° F. This limited thermal exposure is due to the shortened hot pressing period and the use of the brazing process.

The diamonds are also subjected to a number of different forces that may cause the diamonds to be lost from the bit.

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