Chemical synthesis method for fabricating boron carbide powders

Patent metadata

Field	Value
Publication number	US-11465905-B2
Application number	US-201916658175-A
Country	US
Kind code	B2
Filing date	Oct 21, 2019
Priority date	Oct 21, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A chemical synthesis method to fabricate boron carbide to obtain boron carbide fine powders includes the steps of: (A) formulating a precursor solution including a boron source, a liquid organic carbon source and a catalyst; (B) subjecting the precursor solution to a pyrolytic reaction in the presence of electromagnetic radiation to obtain a boron carbide precursor; and (C) subjecting the boron carbide precursor to a thermal energy treatment in the presence of thermal energy to obtain boron carbide fine powders.

First claim

What is claimed is:

1. A chemical synthesis method to fabricate boron carbide powders, comprising:
(A) formulating a precursor solution comprising a boron source, a liquid organic carbon source and a catalyst;
(B) subjecting the precursor solution in the absence of a magnesium-containing material to a pyrolytic reaction in the presence of electromagnetic radiation to obtain a boron carbide precursor; and
(C) subjecting the boron carbide precursor to a thermal energy treatment in the presence of thermal energy to obtain boron carbide fine powders.

2. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron source is selected from a group consisting of ammonia borane, a borane, metaboric acid, a boron oxide, boric acid and a boron halide.

3. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the liquid organic carbon source is selected from a group consisting of an organic acid and an alcohol.

4. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the catalyst is selected from a group consisting of nano-carbon, graphene, graphite powder, nano-boron oxide and a quaternary ammonium compound and the catalyst has a D50 particle size not greater than 0.1 μm.

5. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein a weight of the catalyst is not greater than 5% of a total weight of the precursor solution.

6. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the electromagnetic radiation is microwave vacuum radiation of a power in a range of 800 W-1000 W at a temperature of 350° C.-700° C. for 10 minutes to 50 minutes.

7. The chemical synthesis method to fabricate boron carbide powders according to claim 6 , wherein the microwave vacuum radiation is performed in a first step at a first temperature followed by a second step at a second temperature not lower than the first temperature.

8. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the thermal energy treatment is selected from a group consisting of atmosphere calcination, high-frequency calcination and microwave calcination.

9. The chemical synthesis method to fabricate boron carbide powders according to claim 8 , wherein the atmosphere calcination is carried out in the presence of an inert gas at a temperature of 1200° C.-1600° C. for 1 hour to 5 hours.

10. The chemical synthesis method to fabricate boron carbide powders according to claim 8 , wherein the high-frequency calcination is carried out in the presence of an inert gas and of oscillation frequency not less than 100 kHz at a temperature of 1200° C.-1600° C. for 1 hour to 5 hours.

11. The chemical synthesis method to fabricate boron carbide powders according to claim 8 , wherein the microwave calcination is carried out in the presence of a protective gas and of a power in a range of 1500 W-2200 W at a temperature of 1200° C.-1600° C. for 1 hour to 5 hours.

12. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron carbide fine powders have a D50 particle size not greater than 0.5 μm.

13. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron carbide fine powders have a mean particle size not greater than 100 nm.

14. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron carbide fine powders have purity not less than 95%.

15. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron carbide fine powders have an oxygen atomic content less than 3%.

16. The chemical synthesis method to fabricate boron carbide powders according to claim 1 , wherein the boron carbide fine powders have a magnesium atomic content less than 1%.

Assignees

• Nat Chung Shan Inst Science & Tech

Inventors

• Hsu Wei-Ting
• Chen Yen-Chung
• Wang Hui-Chun
• Huang Ker-Jer

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• B01J27/20

  Carbon compounds · CPC title

• B01J21/18

  Carbon · CPC title

• B01J21/02

  Boron or aluminium; Oxides or hydroxides thereof · CPC title