TW202210414A - Refractory material - Google Patents

Abstract

This refractory material is a Si-SiC material with SiC particles as the main aggregate and metallic Si contained between the SiC particles. Furthermore, the average particle size of the SiC particles, which are the aggregate, is 15 [mu]m or less, and when the cross section of the refractory material is observed, 100 or more pores in the range of 0.05-25 [mu]m are present in the range of 100*100 [mu]m.

Description

Refractory

This application claims priority based on Japanese Patent Application No. 2020-150060 filed on September 7, 2020. The entire contents of this application are incorporated herein by reference. This specification discloses the technology related to refractory materials. In particular, a technique for a Si—SiC based refractory material containing metallic Si between SiC particles has been disclosed.

Japanese Patent Laying-Open No. 2004-18332 (hereinafter referred to as Patent Document 1) discloses a technique concerning a Si—SiC based refractory material (silicon/silicon carbide composite material). The refractory material of Patent Document 1 is composed of SiC particles having an average particle diameter of 0.01 to 2 µm, SiC particles having an average particle diameter of 0.1 to 10 µm, and metal Si dispersed among the SiC particles.

[The problem to be solved by the invention]

SiC-SiC-based (Si-impregnated SiC) disperses metallic Si among SiC particles serving as aggregates, thereby improving properties such as toughness and mechanical strength of the refractory. However, in order to reduce the thickness of the refractory material or increase the durability (longer life), it is necessary to further improve the properties. The purpose of this specification is to provide a high-strength refractory among Si-SiC-based refractories. [means to solve the problem]

The refractory material disclosed in the present specification may be a Si—SiC material in which SiC particles are mainly used as aggregates, and metal Si is contained between the SiC particles. In addition, the average particle diameter of SiC particles serving as aggregates is 10 μm or less, and when the cross section of the refractory material is observed, there are 100 or more pores of 0.05 μm to 25 μm in the range of 100 μm×100 μm. In addition, this refractory material can be formed into a roll, a setter for firing, and a beam for a heating furnace.

The refractory material disclosed in this specification can be used as a constituent member of a heating furnace or a member for use in a heating furnace. Specifically, it can be utilized as a wall material of a heating furnace, a beam, a roll of a continuous heating furnace, a carrier for firing on which an object to be fired (object to be heated) is placed, and the like.

The refractory may be a Si—SiC refractory in which SiC particles are used as aggregates, and metal Si is contained between the SiC particles. The heat resistance of the refractory material can be improved by using SiC particles with excellent heat resistance as the main body of the aggregate. In addition, "using SiC particles as the main body of the aggregate" means that the ratio of the SiC particles in the total mass of the aggregate is 50 mass % or more. That is, the aggregate constituting the refractory material may contain particles other than SiC particles. In addition, the proportion of the SiC particles in the aggregate may be 60 mass % or more, 70 mass % or more, 80 mass % or more, 90 mass % or more, or 95 mass % or more. In addition, the refractory material may contain, for example, B ₄ C particles and C particles in addition to the SiC particles as aggregates.

The average particle diameter of the SiC particles may be 15 μm or less. Thereby, the structure (structural structure) of the refractory material can be densified, and the mechanical strength of the refractory material can be improved. The average particle size of the aggregates (SiC particles) may be 10 μm or less, 7 μm or less, 5 μm or less, 3 μm or less, or 1 μm or less. In addition, the minimum particle diameter of the aggregate may be 0.05 μm or more. Agglomeration of aggregates (particles) can be suppressed during the production of refractory materials. In addition, the maximum particle diameter of the aggregate may be 15 μm or less. It is possible to prevent the aggregate itself from becoming a defect in the structural structure of the refractory, and to suppress the decrease in the mechanical strength of the refractory. The particle diameters (average particle diameter, minimum particle diameter, and maximum particle diameter) of the SiC particles can be confirmed by observing the cross section of the refractory material with a scanning electron microscope (SEM) or the like.

The refractory material may have 100 or more pores of 0.05 μm or more and 25 μm or less in the range of 100 μm×100 μm in the cross section of the refractory material. In other words, small-sized pores (pores of 0.05 μm or more and 25 μm or less) can be dispersed in the inside of the refractory material. The presence of large-sized pores (eg, pores larger than 50 μm) in the interior of the refractory can be suppressed, and the mechanical strength of the refractory can be improved. That is, the mechanical strength of the refractory material is improved by suppressing the presence of large-sized pores that may become the origin of failure in the interior of the refractory material. In addition, the size of the pores is the same as the particle size of the aggregate, which can be confirmed by observing the cross section of the refractory material with a scanning electron microscope or the like. Specifically, the size of the pores can be confirmed by observing the range of 100×100 μm in the cross section of the refractory material, and measuring the maximum diameter of the pores appearing in this range.

In addition, the porosity (apparent porosity) of the refractory material may be 1% or less. Thereby, the mechanical strength of a refractory material is improved. The porosity (apparent porosity) of the refractory material may be 0.8% or less, 0.6% or less, or 0.5% or less. In addition, the porosity of the refractory material can be measured according to JIS R2205-1992.

As described above, the refractory material disclosed in this specification contains metal Si between SiC particles. The ratio of metal Si in the refractory material may be 20 mass % or more and 60 mass % or less. If the ratio of metal Si in the refractory material is 60 mass % or less, the generation of internal cracks can be suppressed in the production process of the refractory material (mainly, the firing process). In addition, the ratio of metal Si in the refractory material may be 55 mass % or less, 50 mass % or less, 45 mass % or less, 40 mass % or less, or 35 mass % or less. In addition, if the proportion of metal Si in the refractory material is 20 mass % or more, the metal Si can sufficiently fill the gaps between the SiC particles (the increase in apparent porosity is suppressed). The ratio of metal Si in the refractory material may be 30 mass % or more or 40 mass % or more.

Figure 1 shows a roll 10 used in a heating furnace (not shown). The roller 10 has a cylindrical shape having a through hole 12 and is formed of Si—SiC. The roll 10 is an example of a refractory material. The roller 10 is formed of SiC particles having a particle diameter of 0.4 to 15 μm and an average particle diameter of 30 μm as aggregates. In addition, metal Si exists between the SiC particles. In addition, the particle diameter of the aggregate (SiC particle) was calculated by acquiring an SEM image of the cross section of the central portion of the roller 10 and measuring the shape of the aggregate existing in the range of 100 μm×100 μm in the image. In addition, the aggregates (SiC particles) and the substances between the aggregates (metal Si) were identified by elemental analysis of the acquired SEM images using EDS.

In the range of 100 μm×100 μm in the acquired SEM image, 722 pores of 0.05 μm or more and 25 μm or less were confirmed, and no pores larger than 15 μm were confirmed. The porosity (apparent porosity) of the roll 10 was 0.5%. As a result of the bending strength test of the roll 10 in accordance with JIS R1601-2008, it was 448 MPa. In addition, the roll 10 is manufactured by the extrusion molding method. Since the extrusion molding method is well known, its description is omitted.

Figure 2 shows the carrier 14 used in a heating furnace (not shown). The carrier 14 has the same characteristics as the roller 10 . The carrier 14 may be manufactured by a pressing method.

Figure 3 shows the beams 16 constituting the heating furnace (not shown). As shown in (a) and (b), the beam 16 is cylindrical and solid. The beam 16 can be manufactured by extrusion molding. [Example]

Refractory materials (Samples 1 to 9) having different particle diameters (average particle diameters) of aggregates (SiC particles) were produced, and the bending strength was measured. FIG. 4 shows the particle size of aggregates used in the production of each sample. As a specific manufacturing method of the refractory material, first, using the aggregate shown in Fig. 4, a cylindrical (roll-shaped) molded body with an outer diameter of 38 mm, an inner diameter of 25 mm, and a length of 1000 mm is manufactured by an extrusion molding machine, and the molded body is heated at a temperature of 1000 mm. Dry at 100°C for more than 24 hours. Next, after being impregnated with metal Si, it was fired at 1600° C. in an inert gas (Ar) atmosphere to obtain a roll-shaped refractory material of Si—SiC quality.

The bending strength of the obtained samples 1 to 9 was measured. The bending strength was measured according to JIS R1601-2008. FIG. 4 shows the measurement result of bending strength. In addition, in Fig. 4, together with the measurement results of flexural strength, samples with a flexural strength of 350 MPa or more are shown as "◎", samples of 300 MPa or more and less than 350 MPa are shown as "○", and samples of 200 MPa or more and less than 300 MPa are shown as "○". The samples with "△" and less than 200 MPa are indicated by "X". "◎" and "○" are pass grades. In addition to the bending strength of the samples 1 to 9, the particle diameters of the SiC particles (average particle diameter, minimum particle diameter, and maximum particle diameter), the number of pores in the cross-sectional observation in the range of 100 μm×100 μm, and the pores were also measured. Evaluation of rate, formability and shape retention.

The particle diameters (average particle diameter, minimum particle diameter, and maximum particle diameter) of SiC particles were calculated by observing the cross section of the refractory material with SEM and measuring all SiC particles appearing in the range of 100 μm×100 μm. The number of pores is obtained by observing the cross section of the refractory material with SEM, and counting pores (pores of 0.05 μm or more and 25 μm or less) within a range of 100 μm×100 μm. In addition, the porosity (apparent porosity) is measured according to JIS R2205-1992. In addition, the SEM observation of the cross section was performed using TM4000 manufactured by Hitachi High-Technologies Corporation. The results of the number of pores and the porosity are shown in FIG. 4 .

Regarding the formability, the samples after extrusion molding were visually observed, and the samples with no abnormality were evaluated as "⊚", the samples with deformation were evaluated as "○", and the samples with deformation and segmentation (fragments) were evaluated as "○". "△", and a sample that could not be formed due to frequent fragmentation during extrusion was evaluated as "X".

Regarding the shape retention, the samples after extrusion were visually observed, and the samples within the design tolerance range were evaluated as "◎", the samples deviated from the design tolerance by less than 2 mm were evaluated as "○", and the samples deviated from the design tolerance by more than 2 mm were evaluated. It is "△", and the sample which cannot be measured substantially (the shape is not maintained) is evaluated as "X".

As shown in FIG. 4 , it was confirmed that the samples (Samples 1 to 6) in which the average particle diameter of SiC particles was 15 μm or less and the number of pores of 0.05 μm or more and 25 μm or less were 100 or more could obtain good strength (300 MPa or more). In addition, it was confirmed that samples with a maximum particle diameter of SiC particles of 30 μm or less (Samples 1 to 5) obtained particularly good strength (350 MPa or more). In addition, it was confirmed that the samples in which the maximum particle diameter of SiC particles was 15 μm or less (Samples 1 to 3) obtained extremely good strength (400 MPa or more). In addition, the samples (samples 1 to 6) showing good strength all had a minimum particle diameter of 0.05 μm or more and an apparent porosity of 1% or less. In addition, it was confirmed that Samples 1 to 6 were better than Samples 7 to 9 in both formability and shape retention.

As described above, it was confirmed that samples 1 to 3 can obtain extremely high strength refractories. Comparing the samples 1 to 3 and the samples 4 to 6, the samples 1 to 3 are characterized in that the apparent porosity is 0.5% or less. From this result, it was confirmed that the strength of the refractory can be further improved by reducing the apparent porosity of the refractory to 0.5% or less.

In the above-mentioned embodiments, examples of rolls, carriers, and beams using refractory materials are shown, but the refractory materials disclosed in this specification can also be used as components (products) other than those in the above-mentioned examples. parts used. In addition, in the said embodiment, although the example of the column-shaped beam was shown, the beam may be a corner column shape.

The specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the scope of the patent claim includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in this specification or the attached drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or the accompanying drawings can simultaneously achieve a plurality of objectives, and achievement of one of the objectives is itself technically useful.

10: Roller 12: Through hole 14: Firing vehicle 16: Beam for heating furnace

[FIG. 1] shows an example (roll) of a refractory material. [Fig. 2] shows an example of a refractory material (a firing carrier). [FIG. 3] shows an example of a refractory material (a beam for a heating furnace), (a) shows the appearance of the beam for a heating furnace, and (b) shows a cross section of the beam for a heating furnace. [Fig. 4] shows the results of the example.

10: Roller

12: Through hole

Claims (8)

A refractory material, the refractory material is a Si-SiC refractory material with SiC particles as the main body of the aggregate, and metal Si is contained between the SiC particles, the average particle diameter of the SiC particles is 15 µm or less, and when a cross section is observed, it is 100 µm There are more than 100 pores of 0.05µm to 25µm in the range of ×100µm. The refractory material according to claim 1, wherein within the range of 100µm×100µm, the maximum particle size of the SiC particles is 30µm or less. The refractory material according to claim 1 or 2, wherein within the range of 100µm×100µm, the minimum particle diameter of the SiC particles is 0.05µm or more. The refractory material according to any one of claims 1 to 3, wherein the apparent porosity of the refractory material is 1% or less. The refractory material according to any one of claims 1 to 4, wherein the ratio of the metal Si is 20 mass % or more and 60 mass % or less. A roll formed of the refractory material according to any one of claims 1 to 5. A firing carrier formed of the refractory material according to any one of claims 1 to 5. A beam for a heating furnace formed of the refractory material according to any one of claims 1 to 5.

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