Silicon nitride ceramic tool comprising diamond film and method of preparing the same

Patent metadata

Field	Value
Publication number	US-2021237168-A1
Application number	US-202117214979-A
Country	US
Kind code	A1
Filing date	Mar 29, 2021
Priority date	Sep 28, 2018
Publication date	Aug 5, 2021
Grant date	—

Abstract

A cutting tool, including a silicon nitride (Si 3 N 4 ) ceramic substrate, and a diamond film coated on the surface of the Si 3 N 4 ceramic substrate. The diamond film has a thickness of 7-12 μm. The cutting tool includes a tool nose, a blade, and a handle. The blade has a rake angle γ of 5-15°, a clearance angle α of 10-14°, and a helix angle of 15-45°. The blade includes four cutting edges.

First claim

What is claimed is:

1 . A cutting tool, comprising:
a silicon nitride (Si 3 N 4 ) ceramic substrate; and a diamond film coated on a surface of the Si 3 N 4 ceramic substrate, and the diamond film having a thickness of 7-12 μm.

2 . The cutting tool of claim 1 , wherein the cutting tool comprises a tool nose, a blade, and a handle; the blade has a rake angle γ of 5-15°, a clearance angle α of 10-14°, and a helix angle β of 15-45°; and the blade comprises four cutting edges.

3 . The cutting tool of claim 2 , wherein a radius R of the tool nose is 0.18-0.22 mm.

4 . The cutting tool of claim 2 , wherein the blade has a length H1 of 4.7-5.3 mm.

5 . The cutting tool of claim 2 , wherein the cutting tool has a length H2 of 49.5-50.5 mm.

6 . A method of preparing the cutting tool of claim 1 , the method comprising:
1) putting silicon nitride (Si 3 N 4 ) ceramic substrate in a hexane suspension mixed with diamond powders, and ultrasonically vibrating the hexane suspension, to grow diamond seeds on the Si 3 N 4 ceramic substrate; and 2) ultrasonically cleaning the Si 3 N 4 ceramic substrate in acetone for 3-8 min, and then in 92-98% anhydrous alcohol for 2-4 min; drying the Si 3 N 4 ceramic substrate and placing in a hot-wire chemical vapor deposition (CVD) vessel.

7 . The method of claim 6 , wherein prior to 1), a rake face of the silicon nitride (Si 3 N 4 ) ceramic substrate is grinded in diamond slurry on a cast iron grinding plate, and then the rake face is roughened in a nano size by CF4 plasma dry etching.

8 . The method of claim 6 , wherein in 2), the hot-wire chemical vapor deposition (CVD) vessel operates with the following parameters: a filament temperature of 2000-2400° C., a substrate temperature of 750-800° C., a total pressure of 3.0-5.0 kPa, a total flow of 300-350 sccm, a volume ratio of CH 4 /H 2 of 1-3%, and a deposition time of 6-10 h.

9 . The method of claim 6 , wherein a particle size of the diamond powders is 0.5-1 μm.

10 . A method of machining a graphite mold for hot bending of glass for a curved surface mobile phone, the method comprising machining the graphite mold using the cutting tool of claim 1 .

Assignees

• Univ Guangdong Technology

Inventors

• Wang Chengyong
• Zhou Yuhai
• Zheng Lijuan

Classifications

• C04B41/89

  for obtaining at least two superposed coatings having different compositions · CPC title

• C04B41/85

  with inorganic materials · CPC title

• C04B41/5002

  Diamond · CPC title

• C04B41/52

  Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation} · CPC title

• C04B41/009

  characterised by the material treated · CPC title