Method for manufacturing ceramic product containing silicon carbide

Patent metadata

Field	Value
Publication number	US-12553667-B2
Application number	US-202016826381-A
Country	US
Kind code	B2
Filing date	Mar 23, 2020
Priority date	Mar 28, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A method for manufacturing a ceramic product containing silicon carbide, including a step of firing a formed body of a green body containing silicon carbide by transporting the formed body from an inlet to an outlet of a continuous furnace, wherein the continuous furnace includes the inlet, a heating zone, a cooling zone, and the outlet in this order, and a furnace atmosphere in both the heating zone and the cooling zone is an inert gas having an oxygen concentration of 100 ppm by volume or less.

First claim

The invention claimed is:

1 . A method for manufacturing a ceramic product containing silicon carbide, comprising a step of firing a formed body of a green body containing silicon carbide by transporting the formed body from an inlet to an outlet of a continuous furnace, wherein the continuous furnace comprises the inlet, a heating zone, a cooling zone, and the outlet in this order, and a furnace atmosphere in both the entire heating zone and the entire cooling zone is an inert gas having an oxygen concentration of 1 ppm by volume or more and 100 ppm by volume or less,
wherein the cooling zone refers to a range in a traveling direction of the formed body from immediately after a heater provided closest to the outlet to the outlet of the continuous furnace, and the formed body is cooled to at least 530° C. in the cooling zone.

2 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein a flow rate of the inert gas supplied to the continuous furnace is 1 Nm 3 /hr or less per 1 m 3 of a furnace volume.

3 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the cooling zone comprises
at least one through hole formed in a furnace wall and connecting an outside of the furnace and an inside of the furnace; and at least one cooling pipe inserted into the through hole, a gap between the through hole and the cooling pipe being sealed by at least one rubber ring.

4 . The method for manufacturing a ceramic product containing silicon carbide according to claim 3 , wherein the rubber ring is made of fluoro rubber or silicone rubber.

5 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the heating zone comprises
at least one through hole formed in a furnace wall and connecting an outside of the furnace and an inside of the furnace and at least one rod-shaped heater inserted into the through hole, a gap between the through hole and the rod-shaped heater being sealed by at least one rubber ring.

6 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the formed body of the green body further comprises silicon.

7 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the formed body of the green body comprises a pillar-shaped honeycomb structure having an outer peripheral side wall and partition walls disposed inside the outer peripheral side wall, the partition walls defining a plurality of cells which form flow paths for a fluid from one end face to another end face of the pillar-shaped honeycomb structure.

8 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein a porosity of the ceramic product containing silicon carbide is 45% or more.

9 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein a furnace pressure in the heating zone and the cooling zone is higher than an atmospheric pressure outside the furnace.

10 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the oxygen concentration of the inert gas is 3 ppm by volume or more and 100 ppm by volume or less.

11 . The method for manufacturing a ceramic product containing silicon carbide according to claim 1 , wherein the oxygen concentration of the inert gas is 5 ppm by volume or more and 100 ppm by volume or less.

12 . A sealing method for reducing an oxygen concentration in a furnace, comprising:
preliminarily, a step of inspecting a leak of an inert gas in a continuous furnace from a furnace wall with a leak detector, and when the leak of the inert gas is detected by the leak detector, a step of performing a seal to prevent air from an outside of the furnace from flowing into an inside of the furnace at a leak location; and thereafter, performing a method for manufacturing a ceramic product containing silicon carbide, comprising a step of firing a formed body of a green body containing silicon carbide by transporting the formed body from an inlet to an outlet of the continuous furnace, wherein the continuous furnace comprises the inlet, a heating zone, a cooling zone, and the outlet in this order, and a furnace atmosphere in both the entire heating zone and the entire cooling zone is an inert gas having an oxygen concentration of 1 ppm by volume or more and 100 ppm by volume or less, wherein the cooling zone refers to a range in a traveling direction of the formed body from immediately after a heater provided closest to the outlet to the outlet of the continuous furnace, and the formed body is cooled to at least 530° C. in the cooling zone, and wherein the step of inspecting the leak of the inert gas in the furnace from the furnace wall with the leak detector is at least performed on a location where there is a component inserted into a through hole formed on the furnace wall and connecting the outside and inside of the furnace in the cooling zone.

13 . The sealing method for reducing an oxygen concentration in a furnace according to claim 12 , wherein the step of inspecting the leak of the inert gas in the furnace from the furnace wall with the leak detector is also performed on a location where there is a component inserted into a through hole formed on the furnace wall and connecting the outside and inside of the furnace in the heating zone.

14 . The sealing method for reducing an oxygen concentration in a furnace according to claim 12 , wherein the step of performing the seal comprises using a rubber ring.

Assignees

• Ngk Insulators Ltd

Inventors

• Kamei Yoshiyuki
• Ihara Chikashi
• Shimada Masato
• Matsumoto Kazuhi

Classifications

• C04B35/645

  Pressure sintering · CPC title

• F27D2009/0078

  in indirect contact with the charge · CPC title

• F27D2019/0006

  Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value · CPC title

• F27B2007/025

  with different chambers, e.g. treatment zones · CPC title

• C04B35/64 Primary

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title