Drill bit with a moissanite (silicon carbide) cutting element

Abstract

A cutting element for a rotary-type drill bit is disclosed comprising moissanite (silicon carbide) crystals impregnated within and/or coated on the surface of the cutting elements.

Description

RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60 / 509,966, filed on Oct. 9, 2003, the entirety of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Embodiments of the present invention relate to cutting elements for use in drill bits and dental burs. In particular, preferred embodiments of the present invention relate to a cutting element for use in drill bits and dental burs which include moissanite (silicon carbide) as an abrasive material. [0004] 2. Description of the Related Art [0005] Rotary drill bits with no moving elements on them are typically referred to as “drag” bits. Drag bits are often used to drill very hard or abrasive formations, or where high bit rotation speeds are required. [0006] Drag bits are typically made from a solid body of matrix material formed by a powder metallurgy process. The process of manufacturing such bits is known ...

AI Technical Summary

Benefits of technology

[0014] One preferred embodiment of the present invention comprises a rotary drill bit comprising a cutting element comprising moissanite (silicon carbide). In a preferred variation, the drill bit includes a cutting element comprising a continuous phase material impregnated and / or surface coated with moissanite (silicon carbide) crystals. Preferably, the continuous phase material includes a hard, erosion- and wear-resistant material, such as metal carbide, a refractory metal alloy, a ceramic, copper, a copper-based alloy, nickel, a nickel-based alloy, cobalt, a cobalt-based alloy, iron, or an iron-based alloy. In some embodiments, the impregnated and / or coated segment of the bit may include more than one type of crystalline abrasive material in addition to moissanite (silicon carbide), as well as one or more different sizes and structural configurations. The impregnated and / or coated segment may include a particulate mixture of moissanite (silicon carbide), diamond, cubic zirconium, carbonitride, amorphous carbon, and hydrogenated amorphous carbon or any other crystalline material having a hardness of greater than about 900 (Hv).

Problems solved by technology

However, surface set cutting elements also present a disadvantage because, once the cutting elements are worn or sheared from the matrix, the bit has to be replaced because of decreased performance, including decreased rate of penetration.

Although cutting elements having this configuration have significantly expanded the scope of formations for which drilling with diamond bits is economically viable, existing cutting elements are still prone to failure.

External loads due to contact tend to cause failures such as fracture, spalling, and chipping of the diamond layer.

Internal stresses for example, thermal residual stresses resulting from manufacturing process, tend to cause delamination of the diamond layer, by cracks initiating in the diamond layer surface and propagating along the interface.

Excessively high contact stress and high temperature are known to cause severe wear to the diamond layer of cutting elements in percussion bits.

Wear is not a typical failure mode in roller cone drill bits that utilize conventional diamond coated cutting elements.

Instead, fatigue and impact of the diamond coating typically result in spalling or delamination, depending upon the thermal-mechanical properties of the diamond or diamond-like coating.

Inherent in conventional efforts to make a sharp and durable dental instrument is that these materials tend to be brittle, and crack and break.

Breakage during a dental procedure represents danger to the patient.

A piece of the instrument may come loose and not be readily retrievable, or may jam in a tooth crevice, requiring sacrificing some of the tooth.