High-yield synthesis of nanostructured boron phosphide by a pyrotechnic method

Patent metadata

Field	Value
Publication number	US-9790093-B2
Application number	US-201615000593-A
Country	US
Kind code	B2
Filing date	Jan 19, 2016
Priority date	Jan 19, 2016
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A simplified method for synthesizing boron phosphide at high yields. The method requires mixing of boron phosphate and magnesium metal without diluents into a homogenous mixture, loosely packing the mixture at less than 20,000 psi and igniting the mixture using an energy input that is not greater than 20% of the reaction energy output to create a self-propagating high-temperature reaction wherein the boron phosphate and magnesium metal is completely burned during the reaction to synthesize boron phosphide at high yields.

First claim

What is claimed is:

1. A process for producing high yield crystalline boron phosphide comprising:
a. mixing a composition consisting essentially of boron phosphate and magnesium metal into a homogenous mixture;
b. loading the homogenous mixture into a column structure;
c. packing the homogenous mixture at a pressure of 0 psi to 20,000 psi to form a pellet;
d. igniting the pellet using a pyrotechnic igniter wherein said pyrotechnic igniter provides an energy input that is no greater than 218 calories/gram of the pellet to initiate a self-propagating high-temperature synthesis reaction of the pellet; and
c. recovering the crystalline boron phosphide.

2. The process of claim 1 , wherein the mass ratio of the magnesium and boron phosphate is about 1:1.

3. The process of claim 1 , wherein the pyrotechnic igniter provides an energy input at about 2.3 calories to about 11.5 calories.

4. The process of claim 1 , wherein the pyrotechnic igniter provides an energy input is at about 0.025% to about 20% of the heat output of the homogenous mixture.

5. The process of claim 1 , wherein the homogenous mixture is packed at a pressure of up to about 10,000 psi.

6. The process of claim 1 , wherein the homogenous mixture is packed into a powderous column or self-standing pellet form.

7. The process of claim 1 , wherein the column structure consists essentially of a combustible material.

8. The process of claim 1 , wherein the column structure comprises a material that can maintain structural integrity of the column structure at temperatures above 1000° C.

9. The process of claim 1 , wherein the column structure is a tubular structure comprised of cardboard, ceramic, or steel.

10. The process of claim 1 , wherein the homogenous mixture is coated with an ignition composition.

11. The process of claim 1 , wherein the homogenous mixture is packed into the column without any pressure.

12. The process of claim 1 , wherein the particle size of the magnesium metal is less than 74 microns.

13. The process of claim 1 , wherein said pyrotechnic igniter provides an energy input at a rate of 0.9 in/sec to 20 in/sec.

14. A process for increasing the yield of crystalline boron phosphide comprising of:
a. Mixing a composition comprising boron phosphate and magnesium metal into a homogenous mixture, wherein the mass ratio of boron phosphate and magnesium is about 1:1
b. loading the homogenous mixture into a column structure;
c. packing the homogenous mixture at a pressure of 0 psi to 10,000 psi to form a pellet;
d. igniting the pellet using a pyrotechnic igniter wherein said pyrotechnic igniter provides an energy input that is no greater than 218 calories/gram of the pellet at a rate of 0.9 in/sec to 20 in/sec to the pellet to initiate a self-sustaining high temperature synthesis reaction of the pellet; and
e. recovering the crystalline boron phosphide.

Assignees

• Us Army

Inventors

• Luan Zhaohua
• Morris Lauren A
• Shaw Anthony P
• Haines Christopher D
• Poret Jay C

Classifications

• C01B25/084 Primary

  of boron · CPC title