Method for synthesizing extremely high-temperature melting materials

• US 6,967,011 B1
• Filed: 12/02/2002
• Issued: 11/22/2005
• Est. Priority Date: 12/02/2002
• Status: Expired due to Fees

• Current Assignee: US Department of Energy (Government of the United States of America)
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Saboungi, Marie-Louise, Glorieux, Benoit
• Primary Examiner(s): Langel, Wayne A.
• Application Number:
  US10/307,478
• Time in Patent Office: 1,086 Days
• Field of Search: 423/289, 423/297, 423/249, 423/250, 423/251, 423/252, 423/254, 423/263
• US Class Current: 423/249
• CPC Class Codes: C01B 35/04 Metal borides

Abstract

The invention relates to a method of synthesizing high-temperature melting materials. More specifically the invention relates to a containerless method of synthesizing very high temperature melting materials such as borides, carbides and transition-metal, lanthanide and actinide oxides, using an Aerodynamic Levitator and a laser. The object of the invention is to provide a method for synthesizing extremely high-temperature melting materials that are otherwise difficult to produce, without the use of containers, allowing the manipulation of the phase (amorphous/crystalline/metastable) and permitting changes of the environment such as different gaseous compositions.

Claims

1. A process for synthesizing a boride compound, comprising the steps of:

a) Mixing boron and at least one metal selected from the group consisting of transition, lanthanide and actinide metals in a stoichiometric ratio corresponding to the boride compound forming a feedstock, the feedstock having a spherical pellet shape capable of levitation;

b) Placing the feedstock on a nozzle of an aerodynamic levitator, the aerodynamic levitator having a levitation chamber, conical nozzle, a gas laser, a pyrometer, a camera, and a vacuum pump;

c) Clearing the levitation chamber of the aerodynamic levitator of any potential contaminant gas or materials using the levitator'"'"'s vacuum pump;

d) Filling the reaction chamber of the aerodynamic levitator with a first argon;

e) Levitating the feedstock using the aerodynamic levitator, the levitator using a second argon gas to levitate the feedstock, the flow of the second argon gas being increased or decreased to control the position of the feedstock, levitation being based on the rate of flow of the second argon gas;

f) Heating the levitating feedstock using the gas laser to a minimum of 200°

C. above the boride compound'"'"'s melting point;

g) When the elements/compounds of the feedstock begin to interact with each other and their surfaces begin to melt together, increasing the power of the laser by between 20–

70%, continuing to heat the feedstock until the feedstock is completely molten and the temperature begins to stabilize, the interaction between the feedstock forming a boride compound;

h) Cooling the resulting boride compound.

2. A process according to claim 1, wherein the boron and at least one metal are in powdered form.

3. A process according to claim 1, wherein the boron and at least one metal are compressed into a spherical pellet using a powder compressor.

4. A process according to claim 1, wherein the feedstock is placed on the nozzle of the aerodynamic levitator using a tweezers or pliers.

5. A process according to claim 1, wherein the pressure within the levitation chamber is maintained between 0.7 and 1.5 bar.

6. A process according to claim 1, wherein the laser is a CO₂ laser.

7. A process according to claim 1, wherein the cooling of the reactants is gradual, the power of the laser being slowly reduced, producing a crystalline material.

8. A process according to claim 1, wherein the cooling of the reactants is rapid, the power of the laser being completely shut off, producing an amorphous material.