# US 10,246,334 B2 · Method of producing heterophase graphite

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- Number: US 10,246,334 B2
- Document ID: US10246334B2
- Status: Granted
- Kind: B2
- Application number: 15/434,088
- Filed: 2017-02-16
- Published: 2018-06-28
- Granted: 2019-04-02
- Earliest claimed: 2016-12-22
- Assignees: National Chung Shan Institute of Science and Technology
- Applicants: National Chung Shan Institute of Science and Technology
- Inventors: Dai-Liang Ma; Cheng-Jung Ko; Bang-Ying Yu; Tsao-Chun Peng
- Web page: https://patentgrep.com/patent/US10246334B2

## CPC

- C01B 32/21: After-treatment
- C01B 32/205: Preparation
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}

## Abstract

A method of producing a heterophase graphite, including the steps of (A) providing a silicon carbide single-crystal substrate; (B) placing the silicon carbide single-crystal substrate in a graphite crucible and then in a reactor to undergo an air extraction process; and (C) performing a desilicification reaction on the silicon carbide single-crystal substrate in an inert gas atmosphere to obtain 2H graphite and 3R graphite, so as to directly produce lumpy (sheetlike, crushed, particulate, and powderlike) 2H graphite and 3R graphite, and preclude secondary contamination of raw materials which might otherwise occur because of a crushing step, an oxidation step, and an acid rinsing step.

## Claims

### Claim 1

A method of producing a heterophase graphite, comprising the steps of:
(A) providing a silicon carbide single-crystal substrate;
(B) placing the silicon carbide single-crystal substrate in a graphite crucible and then in a reactor to undergo an air extraction process; and
(C) performing a desilicification reaction on the silicon carbide single-crystal substrate in an inert gas atmosphere to obtain 2H graphite and 3R graphite;
wherein the air extraction process entails creating a vacuum in the synthesis furnace to remove nitrogen and oxygen therefrom and raising the temperature of the synthesis furnace to 900° C.˜1400° C.

### Claim 2 (depends on 1)

The method of claim 1, wherein the silicon carbide single-crystal substrate is 10 μm˜10000 μm thick and is one of a silicon carbide wafer, a silicon carbide ingot, a silicon carbide chip, and a silicon carbide block.

### Claim 3 (depends on 1)

The method of claim 1, wherein the silicon carbide single-crystal substrate is divided by a hermetic seal material into a reactive monocrystalline crystal surface and a non-desilicified surface.

### Claim 4 (depends on 1)

The method of claim 1, wherein the desilicification reaction occurs to the reactive monocrystalline crystal surface of the carbon phase to produce 2H graphite.

### Claim 5 (depends on 1)

The method of claim 1, wherein the desilicification reaction occurs to the reactive monocrystalline crystal surface of the silicon phase to produce 3R graphite.

### Claim 6 (depends on 3)

The method of claim 3, wherein the hermetic seal material comprises one selected from the group consisting of colloidal graphite, graphite film, TaC film, WC film, and metal carbide.

### Claim 7 (depends on 1)

The method of claim 1, wherein the desilicification reaction occurs at a reaction temperature of 1800° C.˜2200° C. and a reaction pressure of 0.001 torr˜100 torr.

### Claim 8 (depends on 1)

The method of claim 1, wherein the silicon carbide single-crystal substrate has a diameter of 2˜6 inches.

### Claim 9 (depends on 5)

The method of claim 5, wherein the 3R graphite is applicable to diamond substrate precursors.

### Claim 10

A method of producing a heterophase graphite, comprising the steps of:
(A) providing a silicon carbide single-crystal substrate;
(B) placing the silicon carbide single-crystal substrate in a graphite crucible and then in a reactor to undergo an air extraction process; and
(C) performing a desilicification reaction on the silicon carbide single-crystal substrate in an inert gas atmosphere to obtain 2H graphite and 3R graphite;
wherein the silicon carbide single-crystal substrate is divided by a hermetic seal material into a reactive monocrystalline crystal surface and a non-desilicified surface.