# US 8,147,573 B2 · Bonding structure and bonding method for cemented carbide element and diamond element, cutting tip and cutting element for drilling tool, and drilling tool

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- Number: US 8,147,573 B2
- Document ID: US8147573B2
- Status: Granted
- Kind: B2
- Application number: 12/575,074
- Filed: 2009-10-07
- Published: 2010-01-28
- Granted: 2012-04-03
- Earliest claimed: 2002-07-26
- Assignees: Mitsubishi Materials Corporation
- Inventors: Kazuo Yamamoto; Tadakazu Ohashi; Akhmadi Wardoyo
- Web page: https://patentgrep.com/patent/US8147573B2

## CPC

- C04B 35/645: Pressure sintering
- B22F 7/06: of composite workpieces or articles from parts, e.g. to form tipped tools {(B22F7/002 takes precedence)}
- C04B 35/52: based on carbon, e.g. graphite
- C04B 35/5626: {based on tungsten carbides}
- C04B 37/006: {consisting of metals or metal salts}
- C04B 37/026: {consisting of metals or metal salts}
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- B23K 35/3006: {Ag as the principal constituent}
- B23K 35/302: {Cu as the principal constituent}
- B23K 2101/002: {Drill-bits}
- B23K 2103/16: Composite materials
- B23K 2103/172: {wherein at least one of the layers is non-metallic}
- B32B 2311/30: Iron, e.g. steel
- B32B 2315/02: Ceramics
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3213: Strontium oxides or oxide-forming salts thereof
- C04B 2235/3215: Barium oxides or oxide-forming salts thereof
- C04B 2235/3275: Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
- C04B 2235/3839: Refractory metal carbides
- C04B 2235/405: Iron group metals
- C04B 2235/427: Diamond
- C04B 2235/442: Carbonates
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/604: Pressing at temperatures other than sintering temperatures
- C04B 2235/6581: Total pressure below 1 atmosphere, e.g. vacuum
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2237/086: Carbon interlayers
- C04B 2237/122: based on refractory metals
- C04B 2237/123: based on iron group metals, e.g. steel
- C04B 2237/124: based on copper
- C04B 2237/30: Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B 2237/36: Non-oxidic
- C04B 2237/363: Carbon
- C04B 2237/40: Metallic
- C04B 2237/406: Iron, e.g. steel
- Y10T 407/25: including cut off tool
- Y10T 407/27: comprising tool of specific chemical composition
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A cutting tip for a drilling tool includes a cemented carbide cutting base, a diamond element supported by the cutting base, and a bonding layer formed between the cutting base and the diamond element in order to bond them. The bonding layer includes diffusion layers and in which one or two or more metals selected from a group consisting of Fe, Ni, Co, Ti, Zr, W, V, Nb, Ta, Cr, Mo, and Hf diffuses into at least one of the diamond or the cement carbide.

## Claims

### Claim 1

A method of producing a cutting tip, comprising:
fabricating a cemented carbide cutting base having a predetermined shape;
fabricating a diamond element by processing a sintered diamond into a predetermined shape;
interposing a metal material including one or two or more metals selected from a group consisting of Fe, Ni, Co, Ti, Zr, W, V, Nb, Ta, Cr, Mo, and Hf between the cemented carbide cutting base and the diamond element; and
performing bonding of said cemented carbide cutting base and said diamond element comprising the steps of:
heating said cemented carbide cutting base, said diamond element, and said metal material;
forming a diffusion layer in which said metal diffuses into at least one of said cemented carbide cutting base or said diamond element; and
bonding said cemented carbide cutting base and said diamond element,
wherein said heating is carried out under conditions A (K) and B(GPa) that satisfy the following two equations simultaneously:
A>1175
B>0.0027×A+0.81,
such that the maximum content of said metals in said diffusion layer of said cemented carbide cutting base is 20 times or greater than the average content of said metals outside the diffusion layer, and 100 times or greater than an average content of said metals in said diamond element than an average content outside the diffusion layer, wherein the measurement is in a cross-section in a transverse direction of said diffusion layer and is made by line analysis using EPMA.

### Claim 2 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said metal material includes at a total of 70% by mass, at least one of Fe and Ni, and said diffusion layer is formed by at least one of Fe and Ni diffusing into the diamond.

### Claim 3 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said metal material includes Co at 70% by mass or greater, and in the step of bonding said cemented carbide cutting base and said diamond element, said diffusion layer is formed by Co diffusing into said cemented carbide while remaining a Co layer.

### Claim 4 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said metal material includes at 70% by mass or greater one or more of the metals selected from the group consisting of Ti, Zr, W, V, Nb, Ta, Cr, Mo, or Hf, and in the step of bonding said cemented carbide cutting base and said diamond element, said diffusion layer is formed by said metal diffusing into at least one of said cemented carbide or said diamond.

### Claim 5 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said diamond is a high heat resistant sintered diamond including a binder phase of 0.1 to 15% by volume, where said binder phase is formed by one or two or more selected from the group consisting of carbonates of Mg, Ca, Sr, and Ba, oxides of Mg, Ca, Sr, and Ba, complex carbonates and complex oxide containing two or more thereof.

### Claim 6 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said metal material has a first layer and a third layer that include Ni at 70% by mass or greater and a second layer interposed between said first layer and said third layer; and said second layer includes at 70% by mass or greater graphite and/or diamond; and in the step of bonding cemented carbide cutting base and said diamond element, said diffusion layer is formed by the Ni diffusing into the diamond of said diamond element.

### Claim 7 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said metal material includes as a whole Ni at 55 to 80% by mass and carbon in total at 20 to 45% by mass.

### Claim 8 (depends on 1)

A method of producing a cutting tip according to claim 1, wherein said heating is carried out while controlling said conditions A (K) and B(GPa) within a region encompassed by the following four coordinates: (1550K, 5.0 GPa), (1550K, 8.0 GPa), (2000K, 8.0 GPa), and (2000K, 6.2 GPa).