Apparatus and methods for sintering

Patent metadata

Field	Value
Publication number	US-12257629-B2
Application number	US-202017315607-A
Country	US
Kind code	B2
Filing date	Dec 7, 2020
Priority date	Jan 9, 2020
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

Disclosed is an apparatus and methods for sintering particulate to make a workpiece.

First claim

We claim:

1. A furnace for sintering a workpiece, the furnace comprising:
a) at least one inductor coil;
b) at least one hollow cylindrical susceptor enclosing a process tube and an infrared heating zone containing a reducing atmosphere, the susceptor comprising a material capable of absorbing electromagnetic energy from the coil to generate radiant infrared heat and to shield the heating zone from incident RF heat;
c) at least one insulating layer surrounding the susceptor; and
d) a supply of power for said coil;
wherein the process tube in the furnace is horizontally configured to maintain a flow of the reducing atmosphere to aid in sintering and remove volatiles from the furnace; the inductor coils are energized sufficiently to progressively raise the temperature of the susceptor to heat the heating zone by radiant infrared heat to an effective temperature of 800 to 1500° C. and the sintering temperature within the heating zone comprises a uniform heat distribution.

2. The furnace of claim 1 wherein the incident RF heating mechanism is a current induced in the susceptor producing IR heating in the substantial absence of an eddy current heating in the workpiece.

3. The furnace of claim 1 wherein the susceptor cylinder has a wall thickness of 0.5 to 2 centimeters.

4. The furnace of claim 3 wherein the ratio of the outside diameter of the susceptor to the susceptor wall thickness is greater than 4 but less than 12.

5. The furnace of claim 1 wherein the heating of the heat zone is by infrared heat and not by a current induced by radio frequency energy.

6. The furnace of claim 1 wherein the furnace has a construction consisting essentially of the inductor coil, the insulation layer, the susceptor and the process tube with heating zone therein.

7. The furnace of claim 6 wherein the insulating layer is a ceramic insulator.

8. The furnace of claim 1 wherein the coil is water cooled.

9. The furnace of claim 1 wherein the process tube comprises a silicon carbide coating.

10. The furnace of claim 1 wherein the susceptor comprises graphite.

Assignees

• Tundra Composites Llc
• Tundra Compoistes Llc

Inventors

• Heikkila Kurt
• Williams Rodney

Classifications

• F27D11/06

  Induction heating, i.e. in which the material being heated, or its container or elements embodied therein, form the secondary of a transformer · CPC title

• F27B9/36

  Arrangements of heating devices · CPC title

• F27D11/12

  with electromagnetic fields acting directly on the material being heated · CPC title

• F27D2099/0015

  Induction heating · CPC title

• F27D2099/0028

  Microwave heating · CPC title