Systems and methods for making ceramic powders

Patent metadata

Field	Value
Publication number	US-2019135703-A1
Application number	US-201916241517-A
Country	US
Kind code	A1
Filing date	Jan 7, 2019
Priority date	Jul 8, 2016
Publication date	May 9, 2019
Grant date	—

Abstract

Systems and methods for making ceramic powders configured with consistent, tailored characteristics and/or properties are provided herein. In some embodiments a system for making ceramic powders, includes: a reactor body having a reaction chamber and configured with a heat source to provide a hot zone along the reaction chamber; a sweep gas inlet configured to direct a sweep gas into the reaction chamber and a sweep gas outlet configured to direct an exhaust gas from the reaction chamber; a plurality of containers, within the reactor body, configured to retain at least one preform, wherein each container is configured to permit the sweep gas to flow therethrough, wherein the preform is configured to permit the sweep gas to flow there through, such that the precursor mixture is reacted in the hot zone to form a ceramic powder product having uniform properties.

First claim

1 - 36 . (canceled)

37 . A method for carbothermically producing a ceramic powder, the method comprising:
a) preheating at least one container in a staging zone, wherein the at least one container comprises at least one preform, wherein the preform comprises carbon; b) moving the at least one container into a reactor body, wherein the reactor body comprises a reaction zone; c) carbothermically reacting the at least one preform in the reaction zone thereby producing a ceramic powder, wherein the carbothermically reacting comprises reducing, via the carbon of the preform, a metal compound of the preform to a metal carbide, a metal boride, or a metal nitride; and d) moving the at least one container from the reactor body to a receiving zone.

38 . The method of claim 37 , comprising flowing, during at least the carbothermically reacting step, a sweep gas into the at least one container.

39 . The method of claim 38 , wherein the at least one preform comprises a porosity, wherein the flowing comprises flowing the sweep gas through at least one pore of the at least one preform.

40 . The method of claim 37 , wherein the carbothermically reacting step comprises a reaction time, wherein the reaction time is from 0.5 to 12 hours.

41 . The method of claim 37 , wherein the ceramic powder is selected from the group consisting of titanium diboride, boron carbide, boron nitride, aluminum nitride, silicon aluminum nitride, zirconium diboride, silicon aluminum oxy-nitride, titanium carbide, silicon carbide, titanium nitride, aluminum carbide, and combinations thereof.

42 . A system comprising:
a) a staging area, wherein the staging area comprises at least one container, wherein the at least one container comprises at least one preform, and wherein the at least one preform comprises carbon and at least one of a metal oxide and boric acid; b) a reactor body adapted to receive the at least one container from the staging area; c) a receiving unit adapted to receive the at least one container from the reactor body; d) a heat source coupled to the reactor body, wherein the heat source is configured to produce carbothermic reaction temperatures relative to the at least one preform.

43 . The system of claim 42 , wherein the reactor body comprises a sweep gas inlet and a sweep gas outlet.

44 . The system of claim 42 , wherein at least the reactor body comprises a plurality of containers in sequential alignment.

45 . The system of claim 42 , wherein the staging area comprises a one-way valve or a two-way valve.

46 . The system of claim 42 , wherein the reactor body comprises a first seal, wherein the first seal is in fluid communication with the staging area.

47 . The system of claim 42 , wherein the reactor body comprises a second seal, wherein the second seal is in fluid communication with the receiving unit.

48 . The system of claim 42 , wherein the at least one container comprises a sidewall, wherein the sidewall comprises a mechanical device adapted to attach the at least one container to the reactor body.

49 . The system of claim 42 , wherein the at least one container comprises at least one aperture.

50 . The system of claim 42 , wherein the reactor body comprises a reaction chamber, wherein the at least one preform comprises a gas channel, and wherein the gas channel comprises an area fraction of from 0.05 to 0.8 of a cross-sectional area of the reaction chamber.

51 . A preform comprising:
a) carbon; and b) at least one of a metal oxide and boric acid;
wherein the carbon comprises from 10 wt. % to 35 wt. % of the preform, and wherein the balance of the preform consists essentially of metal oxide(s), boric acid and combinations thereof.

52 . The preform of claim 51 , wherein the preform at least comprises titanium dioxide and wherein the titanium dioxide comprises from 20 wt. % to 50 wt. % of the preform.

53 . The preform of claim 52 , wherein the preform at least comprises boric acid and wherein the boric acid comprises from 30 wt. % to 70 wt. % of the preform.

54 . The preform of claim 51 , wherein the preform comprises a plurality of granules, and wherein the preform comprises an inter-granular porosity and an intra-granular porosity.

55 . The perform of claim 51 , wherein the preform is a solid, predefined geometric shape.

Assignees

• Alcoa Usa Corp

Inventors

• Mcmillen James C
• Sworts Lance M
• Mosser Benjamin D
• Shanta Iii Charles Robert

Classifications

• C04B35/56

  based on carbides {or oxycarbides (containing free metal binder C22C29/00)} · CPC title

• B01J4/00 Primary

  Feed {or outlet} devices; Feed or outlet control devices (feed or outlet devices for pressure vessels B01J3/02 {; feeding of particles into and evacuation of particles out of the reactor B01J8/0015}) · CPC title

• B01J2219/1928

  hexagonal · CPC title

• B01J8/10

  moved by stirrers or by rotary drums or rotary receptacles {or endless belts} · CPC title

• C22C29/14

  based on borides · CPC title