Nanostructured silicon nitride synthesis from agriculture waste

Patent metadata

Field	Value
Publication number	US-10239757-B2
Application number	US-201715606425-A
Country	US
Kind code	B2
Filing date	May 26, 2017
Priority date	Jun 16, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A method of making Si 3 N 4 nanotubes and nanorods comprising adding agricultural husk material powder to a container, wherein the container is a covered boron nitride crucible, creating an inert atmosphere of nitrogen inside the container, applying heat, heating the agricultural husk material, and reacting the agricultural husk material and forming silicon nitride, wherein the silicon nitride is nanotubes and nanorods.

First claim

What we claim is:

1. A method of making Si 3 N 4 nanotubes and nanorods comprising:
adding agricultural husk material powder to a container;
wherein the container is a covered boron nitride crucible;
creating an inert atmosphere of nitrogen inside the container;
applying heat;
heating the agricultural husk material; and
reacting the agricultural husk material and forming silicon nitride;
wherein the silicon nitride is nanotubes and nanorods,
cooling the silicon nitride nanotubes and nanorods to room temperature;
transferring the silicon nitride nanotubes and nanorods to an Al 2 O 3 crucible; and
heating the silicon nitride nanotubes and nanorods in the Al 2 O 3 crucible in a furnace;
wherein the step of heating the silicon nitride nanotubes and nanorods in the Al 2 O 3 crucible in a furnace is at 700° C. in O 2 .

2. The method of making Si 3 N 4 nanotubes and nanorods of claim 1 further comprising the step of:
heating the agricultural husk material to a temperature of about 1300-1500° C.

3. The method of making Si 3 N 4 nanotubes and nanorods of claim 2 wherein said step of heating is for 2-10 hours.

4. The method of making Si 3 N 4 nanotubes and nanorods of claim 3 wherein the step of heating the silicon nitride nanotubes and nanorods in the Al 2 O 3 crucible in a furnace at 700° C. in O 2 is for 4 hours.

5. The method of making Si 3 N 4 nanotubes and nanorods of claim 3 wherein the step of heating the silicon nitride nanotubes and nanorods in the Al 2 O 3 crucible in a furnace at 700° C. in O 2 eliminates excess carbon via O 2 purification.

6. The method of making Si 3 N 4 nanotubes and nanorods of claim claim 3 wherein the silicon nitride nanotubes and nanorods are pure α-Si 3 N 4 formed by carbothermal reduction of SiO 2 .

7. A method of producing nanorods and nanoparticles of silicon nitride comprising:
washing husks in distilled water;
pulverizing husks into fine husk powder using high energy mill with stainless steel milling media;
pressing the fine husk powder into pellets;
heating the pellets;
heating the pellet to a temperature of about 1300-1500° C.;
maintaining the temperature of the pellets at about 1300-1500° C.; and
cooling the pellets comprising nanorods and nanoparticles of silicon nitride;
wherein the nanotubes and nanorods of silicon nitride are pure α-Si 3 N 4 formed by carbothermal reduction of SiO 2 .

Assignees

• Us Navy

Inventors

• Qadri Syed B
• Rath Bhakta B
• Gorzkowski Iii Edward P

Classifications

• C01B21/0685 Primary

  Preparation by carboreductive nitridation · CPC title

• C01P2004/13

  Nanotubes · CPC title

• C01P2004/16

  Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title