High-throughput powder synthesis system

• US 20060266216A1
• Filed: 05/24/2005
• Published: 11/30/2006
• Est. Priority Date: 05/24/2005
• Status: Abandoned Application

• Current Assignee: Cabot Corporation
• Original Assignee: Cabot Corporation
• Inventors: Dericotte, David E.
• Application Number:
  US11/136,277
• Publication Number:
  US 20060266216A1
• Time in Patent Office: Days
• US Class Current: 95/273
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 9/026 Spray drying of solutions or suspensions
• CPC Class Codes: B22F 9/24 starting from liquid metal compounds, e.g. solutions

Abstract

The powder synthesis system integrates “on-the-fly” precursor formulation and delivery, control of carrier gas flow rate and temperatures of a multi-zone reactor (to control time-temperature history of the particles in the reactor), with rapid filtering/collection equipment into a powder synthesis process that is representative of actual manufacturing time-temperature conditions. A control system provides automatic operation and data acquisition, while requiring minimal operator involvement. The system includes a delivery stage, a production stage, and a collection stage. The collection stage uses a camera style filter apparatus to collect the powder with minimal loss and isolates each sample to prevent contamination.

Claims

1. A collector for a powder synthesis system, comprising:

a filter assembly including a feed zone, a collection zone, and a storage zone, and an elongated porous filter extending from the feed zone to the storage zone through the collection zone along a feed path, wherein the filter has a surface that is exposed when positioned in the collection zone;

a driver connected to the filter assembly that indexes the filter to positions along the feed path to progressively expose different areas of the surface of the filter in the collection zone for powder collection and advance the exposed areas of the surface of the filter toward the storage zone;

a film supply adjacent the storage zone that applies film to the surface of the filter in the storage zone to cover the previously exposed areas of the surface of the filter for retaining collected powder; and

an inert gas source in communication with the feed zone and the storage zone that provides a continuous flow of inert gas from the feed zone toward the collection zone and from the storage zone toward the collection zone thereby creating a barrier around the collection zone and an oxygen free environment around at least the storage zone.

2. The collector of claim 1, further comprising a controller connected to the filter assembly and the driver to control the positioning of the filter.

3. The collector of claim 2, wherein the controller drives the filter to predetermined discrete positions along the feed path for powder collection.

4. The collector of claim 2, wherein the controller drives the filter in a continuous manner for powder collection.

5. The collector of claim 1, further comprising a compound supplier that supplies powder in a stream of carrier gas, wherein the collection zone is exposed to the stream of carrier gas so that the powder is collected on the exposed surface of the filter.

6. The collector of claim 5, wherein the compound supplier includes an injection assembly and a manifold, wherein a combination of compounds are selected and individually injected into the manifold for mixing.

7. The collector of claim 6, wherein the injection assembly includes a coordinated syringe and valve system.

8. The collector of claim 6, wherein the compound supplier further includes a mixer downstream of the manifold.

9. The collector of claim 8, wherein the mixer is an in-line mixer.

10. The collector of claim 8, wherein the mixer is a non-contact ultrasonic mixer.

11. The collector of claim 1, wherein the film applied to the surface of the filter is a polyimide film.

12. The collector of claim 1, wherein the inert gas includes nitrogen.

13. The collector of claim 1, wherein the feed zone comprises a spool of unexposed filter, the storage zone comprises a spool of exposed filter, and the feed path includes a porous grid that supports the filter during exposure.

14. A method of collecting samples in a powder synthesis system having a filter assembly with a feed zone, a collection zone and a storage zone, the method comprising:

providing a flow of powder carried in a carrier gas;

providing an elongated porous filter that extends from the feed zone through the collection zone and to the storage zone;

exposing a portion of the filter to the flow of powder carried in the carrier gas in the collection zone to separate the powder from the carrier gas and accumulate powder on a surface of the exposed portion of the filter;

delivering a continuous flow of inert gas to the feed zone and the storage zone to create a barrier that inhibits powder from leaving the collection zone;

actuating the filter assembly to advance the exposed portion of the filter toward the storage zone and position an unexposed portion of the filter in the collection zone;

applying a film to cover the exposed portion of the filter and the accumulated powder in the storage zone; and

removing the exposed portions of the filter from the storage zone for analysis.

15. The method of claim 14, wherein delivering a continuous flow of inert gas to the storage zone further comprises creating an oxygen free environment around the storage zone.

16. The method of claim 14, wherein actuating the filter assembly includes advancing the exposed portion of the filter to discrete locations in the collection zone.

17. The method of claim 14, wherein actuating the filter assembly includes advancing the exposed portion of the filter in a continuous manner so that powder accumulates along an extended length of the filter.

18. The method of claim 14, further comprising maintaining the filter in a taut condition in the collection zone.

19. A method of synthesizing a high throughput of powder, comprising:

providing an accessible database of operating conditions, including physical data relating to precursor solutions, precursor feed rates, elemental composition of target materials, processing temperatures, carrier gas flow rates, filter specifications, and other system parameters;

calculating variable control values based on the operating conditions;

determining a precursor formulation by selecting from individually stored chemical components;

mixing controlled amounts of the selected chemical components according to the calculated control values;

atomizing the mixture into droplets and entraining the droplets in a carrier gas;

processing the aerosol droplets by heating at a calculated processing temperature and converting the droplets into a fine powder entrained in the carrier gas;

cooling the carrier gas and powder to a calculated cooled temperature;

causing the carrier gas and powder to flow past a porous filter at a calculated rate to separate the powder from the carrier gas;

collecting and storing the powder on a surface of the porous filter; and

automatically monitoring and controlling the variable system parameters and automatically collecting data representative of actual operating conditions.

20. The method of claim 19, further comprising delivering a continuous flow of inert gas toward the collection zone during collection of the powder to inhibit powder from leaving the filter in the collection zone.

21. The method of claim 19, further comprising applying a film to cover the surface of the porous filter after the powder is collected and prior to storage.

22. The method of claim 19, further comprising receiving a signal representative of a condition of the filter to detect discontinuities in the filter.

23. The method of claim 19, wherein mixing controlled amounts of the selected chemical components includes varying the composition in a time dependent manner.

24. The method of claim 19, wherein collecting and storing the powder includes advancing the porous filter each time a different precursor is formulated so that individual powder samples are collected for each precursor formulation.

25. The method of claim 24, further comprising determining the location of a particular powder deposited on the filter based on time dependent mixing of the selected chemical components.