# US 11,441,843 B2 · Refractory container made of a ceramic material, green body for such a container, and method for the manufacture of a refractory container made of a ceramic material, and of a green body provided for this purpose

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- Number: US 11,441,843 B2
- Document ID: US11441843B2
- Status: Granted
- Kind: B2
- Application number: 16/170,173
- Filed: 2018-10-25
- Published: 2019-04-25
- Granted: 2022-09-13
- Earliest claimed: 2017-10-25
- Assignees: WPX Faserkeramik GmbH
- Applicants: WPX Faserkeramik GmbH
- Inventors: Mathias Kunz
- Web page: https://patentgrep.com/patent/US11441843B2

## CPC

- F27D 5/0006: {Composite supporting structures}
- C04B 35/111: Fine ceramics
- C04B 35/62655: {Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying}
- C04B 35/62852: {Alumina or aluminates}
- C04B 35/62894: {with more than one coating layer}
- C04B 35/64: Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F})
- C04B 35/66: Monolithic refractories or refractory mortars, including those whether or not containing clay {(making or repairing of linings F27D1/16)}
- C04B 35/71: Ceramic products containing macroscopic reinforcing agents (C04B35/66 takes precedence {; infiltration of a porous ceramic matrix with a material forming a non-ceramic phase C04B41/00, reaction infiltration with Si in order to form SiC C04B35/573, in order to form Si3N4 C04B35/591})
- C04B 35/80: Fibres, filaments, whiskers, platelets, or the like
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/5224: Alumina or aluminates
- C04B 2235/5228: Silica and alumina, including aluminosilicates, e.g. mullite
- C04B 2235/5236: Zirconia
- C04B 2235/5244: Silicon carbide
- C04B 2235/5248: Carbon, e.g. graphite
- C04B 2235/5256: Two-dimensional, e.g. woven structures
- C04B 2235/5264: characterised by the diameter of the fibers
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/5481: Monomodal
- C04B 2235/602: Making the green bodies or pre-forms by moulding
- C04B 2235/616: Liquid infiltration of green bodies or pre-forms
- C04B 2235/9607: Thermal properties, e.g. thermal expansion coefficient
- F27D: DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

The invention relates to a refractory container 1 for use in a furnace for heat treatment of workpieces, comprising a mat 5 of long fibers that are embedded in a ceramic shell, with the mat 5 being shaped into a container that forms a receiving space for workpieces, and to a green body of such a container 1. Furthermore, advantageous uses of the container 1 as well as a method for manufacturing a green body or container 1 according to the invention are specified.

## Claims

### Claim 1

A refractory container (1) for use in a furnace for heat treatment of workpieces, comprising a mat (5) of long fibers that are embedded in a ceramic shell, with the mat (5) being shaped into a container forming a receiving space for workpieces, characterized in that the mat (5) forms support structures and retaining structures, with the support structures having at least 50% greater flexural strength than the retaining structures, wherein the ceramic shell comprises an oxide ceramic material.

### Claim 2 (depends on 1)

The container (1) as set forth in claim 1, characterized in that the container (1) forms a plurality of openings (7) through which fluid can pass.

### Claim 3 (depends on 1)

The container (1) as set forth in claim 1, characterized in that the support structures form a grid with a first mesh size and the retaining structures form a grid with a second mesh size, with the first and the second mesh sizes being different from one another.

### Claim 4 (depends on 3)

The container (1) as set forth in claim 3, characterized in that the first mesh size is at least twice as large as the second mesh size.

### Claim 5 (depends on 1)

The container (1) as set forth in claim 1, characterized in that a first number of long fibers are embedded in a cross section of the support structures, and a second number of long fibers are embedded in a cross section of the retaining structures, with the first number being at least 50% greater.

### Claim 6 (depends on 1)

The container (1) as set forth in claim 1, characterized in that a first type of long fiber is embedded in a cross section of the support structures, and a second type of long fiber is embedded in a cross section of the retaining structures, with the tensile strength of the first type of long fiber being at least 20% greater.

### Claim 7 (depends on 1)

The container (1) as set forth in claim 1, characterized in that a first type of long fiber is embedded in a cross section of the support structures, and a second type of long fiber is embedded in a cross section of the retaining structures, with the fiber weight of the first type of fiber being greater than the fiber weight of the second type of fiber.

### Claim 8 (depends on 1)

The container (1) as set forth in claim 1, characterized in that the shell of the long fibers embedded in the support structures has different mechanical properties than the shell of the long fibers embedded in the retaining structures.

### Claim 9 (depends on 1)

The container (1) as set forth in claim 1, characterized in that the mat (5) forms at least one kink-free surface, with the support structures in this area extending in two crossed main directions A and A′ and the retaining structures in this area extending in two main directions B and B′.

### Claim 10 (depends on 9)

The container (1) as set forth in claim 9, characterized in that the main directions A and B as well as A′ and B′ coincide or are different.

### Claim 11 (depends on 1)

The container (1) as set forth in claim 1, characterized in that the mat (5) is embodied as a scrim of long fibers.

### Claim 12 (depends on 1)

The container (1) as set forth in claim 1, wherein the mat (5) forms an edge, characterized in that the container (1) forms a collar (6) that mechanically reinforces the edge.

### Claim 13 (depends on 12)

The container (1) as set forth in claim 12, characterized in that the collar (6) comprises a plurality of long fibers that are embedded in a ceramic shell.

### Claim 14 (depends on 13)

The container (1) as set forth in claim 13, characterized in that the fibers in the collar are oriented substantially along the edge of the mat (5).

### Claim 15 (depends on 13)

The container (1) as set forth in claim 13, characterized in that the long fibers in the collar (7) form a scrim.

### Claim 16 (depends on 1)

A green body (2) for a refractory container (1) as set forth in claim 1, comprising a mat (5) of long fibers that is infiltrated with a ceramic slurry.

### Claim 17 (depends on 1)

A method for using a container (1) as set forth in claim 1, characterized in that the container (1) is used in a sintering furnace or in a hardening furnace.

### Claim 18 (depends on 17)

The method as set forth in claim 17, characterized in that the container (1) receives one or more metallic workpieces.

### Claim 19 (depends on 18)

A method for manufacturing a refractory container (1) for use in a furnace for heat treatment of workpieces, comprising the following method steps:
a. manufacturing of a green body (2) as set forth in the method of claim 18, and
b. sintering of the green body (2).

### Claim 20 (depends on 1)

The container (1) as set forth in claim 1, wherein the oxide ceramic material is Al2O3.

### Claim 21 (depends on 20)

The container (1) as set forth in claim 20, wherein the weight proportion of Al2O3 in the matrix is greater than 70%.

### Claim 22 (depends on 20)

The container (1) as set forth in claim 20, wherein Al2O3 is further comprising a zirconium oxide with the weight proportion of ZrO2 in the matrix being greater than 5%.

### Claim 23 (depends on 20)

The container (1) as set forth in claim 20, wherein Al2O3 is further comprising a zirconium oxide dopant with the weight proportion of ZrO2 in the matrix being greater than 5%.