# US 5,700,518 A · Fabrication method for diamond-coated cemented carbide cutting tool

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- Number: US 5,700,518 A
- Document ID: US5700518A
- Status: Granted
- Kind: A
- Application number: 08/712,707
- Filed: 1996-09-12
- Granted: 1997-12-23
- Earliest claimed: 1996-04-26
- Assignees: Korea Institute of Science and Technology
- Inventors: Wook-Seong Lee; Young-Joon Baik; Kwang Yong Eun
- Web page: https://patentgrep.com/patent/US5700518A

## CPC

- C23C 16/0227: {by cleaning or etching}
- C23C 16/27: Diamond only
- C25F 3/02: Etching
- Y10T 407/27: comprising tool of specific chemical composition
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A fabrication method for a diamond-coated cemented carbide cutting tool includes electrolytically etching the surface of a cemented carbide cutting tool with a NaOH or KOH aqueous solution or chemically etching the surface of the cemented carbide cutting tool with a KMnO.sub.4 +KOH aqueous solution, and depositing a diamond film on the cemented carbide cutting tool. A stronger etching effect than by using a Murakami solution can be achieved, and no poisonous material is included in the etchant. In addition, disposal of the waste etchant is made simpler, and the adhesion between the diamond film coating and the cemented carbide cutting tool can be strengthened.

## Claims

### Claim 1

A fabrication method for a diamond-coated cemented carbide cutting tool, comprising;
electrolytically etching a cemented carbide cutting tool with an etchant selected from the group consisting of a NaOH aqueous solution and a KOH aqueous solution;
etching a cobalt binder phase of the electrolytically etched cemented carbide cutting tool with a mixed solution of sulfuric acid and hydrogen peroxide;
seeding the etched cemented carbide cutting tool with a diamond powder slurry; and
depositing a diamond film on the seeded cemented carbide cutting tool.

### Claim 2 (depends on 1)

The fabrication method of claim 1, wherein the concentration of the NaOH aqueous solution is 1.about.70 wt %.

### Claim 3 (depends on 1)

The fabrication method of claim 1, wherein the concentration of the KOH aqueous solution is 1.about.60 wt %.

### Claim 4

A fabrication method for a diamond-coated cemented carbide cutting tool, comprising;
chemically etching a cemented carbide cutting tool with a KMnO.sub.4 +KOH aqueous solution;
etching a cobalt binder phase of the chemically etched cemented carbide cutting tool with a mixed solution of sulfuric acid and hydrogen peroxide;
seeding the etched cemented carbide cutting tool with a diamond powder slurry; and
depositing a diamond film on the seeded cemented carbide cutting tool.

### Claim 5 (depends on 4)

The fabrication method of claim 4, wherein said KMnO.sub.4 +KOH aqueous solution is composed of 1.about.20 wt % KMnO.sub.4, 1.about.60 wt % KOH and balance H.sub.2 O.