JP6364374B2 - Honeycomb structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a honeycomb structure and a manufacturing method thereof. More specifically, the honeycomb structure that is a catalyst carrier and functions as a heater by applying a voltage, in particular, has excellent thermal shock resistance and current-carrying characteristics of the electrode part, and can be manufactured by a simple manufacturing method, and its It relates to a manufacturing method.

  Conventionally, a catalyst supported on a cordierite honeycomb structure has been used to treat harmful substances in exhaust gas discharged from an automobile engine. It is also known to use a honeycomb structure formed of a silicon carbide sintered body for purification of exhaust gas (see, for example, Patent Document 1).

  When the exhaust gas is treated with the catalyst supported on the honeycomb structure, it is necessary to raise the temperature of the catalyst to a predetermined temperature. However, when the engine is started, there is a problem that the exhaust gas is not sufficiently purified because the catalyst temperature is low.

  Therefore, it has been proposed to use a ceramic honeycomb structure as a “heatable catalyst carrier” (see, for example, Patent Document 2). Since such a honeycomb structure generates heat due to Joule heat when an electric current flows, use of the honeycomb structure as, for example, an electric heating catalytic converter (EHC) for exhaust gas purification has been studied. For example, a honeycomb structure described in Patent Document 2 includes a honeycomb structure portion having a porous partition wall and an outer peripheral wall located at the outermost periphery, and a pair of electrode portions disposed on the side surfaces of the honeycomb structure portion, It is equipped with. As a material of the honeycomb structure part and the electrode part, for example, conductive ceramics such as silicon carbide (SiC) and silicon-silicon carbide composite material (Si-SiC) are used.

In addition, as a material for the honeycomb structure, for example, a composite material composed of at least one of Si and SiC and MoSi ₂ and a material for forming a component of an electrically heated catalytic converter has been proposed. (For example, see Patent Document 3).

Japanese Patent No. 4136319 International Publication No. 2011-125815 JP 2014-62476 A

Since the composite material described in Patent Document 3 contains MoSi ₂ in the composite material, the electrical resistivity is lower than that of SiC, SiC-Si, or the like, and the temperature dependence of the electrical resistivity is small. I have it. However, when a composite material containing MoSi ₂ is used as the electrode part of the honeycomb structure, the honeycomb structure part and the electrode part cannot be manufactured by the same firing process, and the manufacturing process of the honeycomb structure is complicated. There was a problem of becoming.

That is, when manufacturing a honeycomb structure provided with an electrode portion made of a composite material containing MoSi ₂ , it is necessary to take the following manufacturing process. First, a honeycomb formed body is manufactured using a raw material for forming a honeycomb structure. Next, the honeycomb formed body is dried to obtain honeycomb dried, and the obtained honeycomb dried body is degreased and fired to obtain a honeycomb structure part (hereinafter also referred to as “honeycomb fired body”). Is made. Then, the electrode part forming raw material containing MoSi ₂ is applied to the side surface of the obtained honeycomb structure part, and the honeycomb structure is manufactured through the drying process, the degreasing process, and the firing process again. Here, when the honeycomb formed body or the honeycomb dried body described above is coated with an electrode part forming raw material containing MoSi ₂ and a honeycomb structure is manufactured by a single degreasing step and a firing step, the degreasing step However, a pulverization phenomenon occurs in the electrode part containing MoSi _2, and it becomes difficult to form an appropriate electrode part. For this reason, in order to manufacture a honeycomb structure having an electrode portion made of a composite material containing MoSi ₂ , the degreasing process and the firing process must be performed twice in the manufacturing process of one honeycomb structure. However, the manufacturing process becomes very complicated, and the manufacturing cost of the honeycomb structure is greatly increased. For these reasons, there is a demand for the development of a honeycomb structure that is excellent in thermal shock resistance and current-carrying characteristics of the electrode part and that can be manufactured by a simple manufacturing method. In particular, there is a strong demand for development of a honeycomb structure capable of manufacturing a honeycomb structure portion and an electrode portion by a single degreasing process and a firing process.

  The present invention has been made in view of the above-described problems. The present invention serves as a catalyst carrier and also functions as a heater by applying a voltage, in particular, a honeycomb structure excellent in the thermal shock resistance and current-carrying characteristics of the electrode part and manufactured by a simple manufacturing method, and its A manufacturing method is provided.

  In order to solve the above-described problems, the present invention provides the following honeycomb structure and a manufacturing method thereof.

[1] A columnar honeycomb structure portion and a pair of electrode portions disposed on a side surface of the honeycomb structure portion, the honeycomb structure portion including a porous partition wall and an outer periphery disposed at an outermost periphery A plurality of cells extending from the first end surface to the second end surface of the honeycomb structure portion by the partition walls, and the honeycomb structure portion is formed of silicon carbide. And a honeycomb structure in which at least a part of the pair of electrode portions is made of a composite material containing TaSi ₂ and silicon.

[2] The honeycomb structure according to [1], wherein the composite material constituting at least a part of the electrode portion further includes silicon carbide.

[3] The honeycomb structure according to [1] or [2], wherein the electrode portion has a thermal expansion coefficient of 5.0 to 8.0 × 10 ⁻⁶ (/ K).

[4] The honeycomb structure according to any one of [1] to [3], wherein the electrode part has an electrical resistivity of 0.001 to 10.0 Ωcm.

[5] The honeycomb structure according to any one of [1] to [4], wherein the electrode portion has a strength of 5 to 30 MPa.

[6] The honeycomb structure portion has a porosity of 30 to 60%, an average pore diameter of 2 to 15 μm, a thickness of the partition wall of 50 to 300 μm, a cell density of 40 to 150 cells / cm ² , and The honeycomb structure according to any one of [1] to [5], wherein an electrical resistance between the pair of electrode portions is 2 to 100Ω.

[7] The honeycomb structure according to any one of [1] to [6], wherein a content ratio of the TaSi _{2 in} the composite material constituting the electrode part is 15 to 78% by volume.

[8] The honeycomb structure according to any one of [1] to [7], wherein a content ratio of the silicon in the composite material constituting the electrode portion is 5 to 43% by volume.

[9] The honeycomb structure according to [2], wherein a content ratio of the silicon carbide in the composite material constituting the electrode portion is 57.5% by volume or less.

[10] A columnar honeycomb formed body having porous partition walls and an outer peripheral wall disposed on the outermost periphery, or a first region and a first region on a side surface of a honeycomb fired body obtained by firing the honeycomb formed body The electrode body forming raw material is applied to each of the two regions, and the applied electrode portion forming raw material is dried and fired to form a pair of electrode portions. A plurality of cells extending from the first end face to the second end face of the honeycomb formed body are partitioned by the partition walls, and the electrode part forming step uses the electrode formed raw material as the honeycomb formed body or the honeycomb. In a cross section orthogonal to the cell extending direction of the fired body, the first region is positioned on the opposite side of the second region with the center of the honeycomb formed body or the honeycomb fired body interposed therebetween. And coating A method for manufacturing a honeycomb structure using a raw material containing at least TaSi ₂ powder and silicon powder as the electrode part forming raw material.

[11] The above [10], wherein the electrode part forming step is a step of applying the electrode part forming raw material to the first region and the second region on the side surface of the honeycomb formed body, respectively. Method for manufacturing the honeycomb structure.

[12] Prior to the firing in the electrode part forming step, the honeycomb formed body or the honeycomb fired body coated with the electrode part forming raw material is degreased at 400 to 550 ° C. in an air atmosphere. ] Or the manufacturing method of the honeycomb structure according to [11].

[13] In the electrode part forming step, the honeycomb formed body or the honeycomb fired body coated with the electrode part forming raw material is fired at 1400 to 1500 ° C. in an Ar atmosphere. [10] to [12] A method for manufacturing a honeycomb structure according to any one of the above.

[14] Any of the above [10] to [13], wherein after the firing in the electrode portion forming step, the fired honeycomb formed body or the honeycomb fired body is oxidized at 1000 to 1350 ° C. in an oxidizing atmosphere. A method for manufacturing a honeycomb structure according to claim 1.

[15] At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ and silicon, and the content ratio of TaSi _{2 in} the composite material is 15 to 78 volumes. %. The method for manufacturing a honeycomb structured body according to any one of the above [10] to [14].

[16] At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ and silicon, and a silicon content ratio of the composite material is 5 to 43% by volume. The method for manufacturing a honeycomb structured body according to any one of [10] to [15].

[17] The method for manufacturing a honeycomb structured body according to any one of [10] to [16], wherein the raw material further containing silicon carbide powder is used as the electrode part forming raw material.

[18] At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ , silicon and silicon carbide, and the silicon carbide content ratio of the composite material is 57. The method for manufacturing a honeycomb structured body according to the above [17], which is 5% by volume or less.

[19] The above-mentioned [10] to [18], wherein the electrode part obtained by firing the electrode part forming raw material has a thermal expansion coefficient of 5.0 to 8.0 × 10 ⁻⁶ (/ K). The manufacturing method of the honeycomb structure in any one.

[20] The honeycomb structure according to any one of [10] to [19], wherein the electrode part obtained by firing the electrode part forming raw material has an electrical resistivity of 0.001 to 10.0 Ωcm. Manufacturing method.

[21] The method for manufacturing a honeycomb structure according to any one of [10] to [20], wherein the electrode part obtained by firing the electrode part forming raw material has a strength of 5 to 30 MPa.

[22] The honeycomb fired body has a porosity of 30 to 60%, an average pore diameter of 2 to 15 μm, a thickness of the partition wall of 50 to 300 μm, a cell density of 40 to 150 cells / cm ² , and The method for manufacturing a honeycomb structure according to any one of [10] to [21], wherein an electrical resistance between the pair of electrode portions is 2 to 100Ω.

The honeycomb structure of the present invention includes a columnar honeycomb structure and a pair of electrode portions disposed on the side surface of the honeycomb structure portion. In the honeycomb structure of the present invention, the honeycomb structure portion is made of a material containing at least one kind of silicon carbide and silicon, and at least a part of the pair of electrode portions is a composite containing at least TaSi ₂ and silicon. Consists of materials. The honeycomb structure of the present invention thus configured is a catalyst carrier and also functions as a heater when a voltage is applied. In particular, the honeycomb structure has an effect of being excellent in thermal shock resistance and current-carrying characteristics of the electrode portion. Moreover, the honeycomb structure of the present invention can be manufactured by a simple manufacturing method. In particular, the honeycomb structure part and the electrode part can be manufactured by a single degreasing process and a firing process, and the manufacturing process can be simplified and the manufacturing cost of the honeycomb structure can be reduced. .

  Moreover, the manufacturing method of the honeycomb structure of the present invention is a manufacturing method for manufacturing the above-described honeycomb structure of the present invention, which can simplify the manufacturing process and reduce the manufacturing cost of the honeycomb structure. can do.

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. 1 is a schematic diagram showing a cross section parallel to a cell extending direction of an embodiment of a honeycomb structure of the present invention. FIG. 1 is a schematic diagram showing a cross section orthogonal to a cell extending direction of an embodiment of a honeycomb structure of the present invention. It is a perspective view which shows typically other embodiment of the honeycomb structure of this invention. It is a schematic diagram which shows the cross section parallel to the cell extending direction of other embodiment of the honeycomb structure of this invention. FIG. 6 is a front view schematically showing still another embodiment of the honeycomb structure of the present invention. FIG. 6 is a front view schematically showing still another embodiment of the honeycomb structure of the present invention. It is a schematic diagram which shows the A-A 'cross section in FIG. FIG. 6 is a side view schematically showing still another embodiment of the honeycomb structure of the present invention.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it is understood that design changes, improvements, and the like can be added as appropriate based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should.

(1) Honeycomb structure:
As shown in FIGS. 1 to 3, an embodiment of the honeycomb structure of the present invention includes a columnar honeycomb structure portion 4, and a pair of electrode portions 21 and 21 disposed on a side surface of the honeycomb structure portion 4. The honeycomb structure 100 is provided. The honeycomb structure part 4 has a porous partition wall 1 and an outer peripheral wall 3 located at the outermost periphery. A plurality of cells 2 extending from the first end surface 11 as one end surface of the honeycomb structure portion 4 to the second end surface 12 as the other end surface are defined in the honeycomb structure portion 4 as fluid flow paths. . In the honeycomb structure 100 of the present embodiment, the honeycomb structure 4 is made of a material containing at least one of silicon carbide and silicon. In the honeycomb structure 100 of the present embodiment, at least a part of the pair of electrode portions 21 and 21 is made of a composite material containing at least TaSi ₂ and silicon. Hereinafter, the “composite material including at least TaSi ₂ and silicon” constituting at least a part of the pair of electrode portions 21 and 21 may be referred to as “TaSi ₂ -containing composite material”.

  The honeycomb structure 100 of the present embodiment configured as described above is a catalyst carrier and also functions as a heater by applying a voltage. In particular, the thermal shock resistance and energization characteristics of the pair of electrode portions 21 and 21 are achieved. The effect is excellent. Moreover, the honeycomb structure 100 of the present embodiment can be manufactured by a simple manufacturing method. In particular, the honeycomb structure part 4 and the electrode parts 21 and 21 can be manufactured by a single degreasing process and a firing process, the manufacturing process can be simplified, and the manufacturing cost of the honeycomb structure 100 can be reduced. Can be reduced. Of course, the honeycomb structure 100 of the present embodiment performs a degreasing process and a firing process on the honeycomb structure part 4, and then further degreases the pair of electrode parts 21 and 21 and the honeycomb structure part 4. What was manufactured by performing a process and a baking process may be used.

  Here, FIG. 1 is a perspective view schematically showing one embodiment of the honeycomb structure of the present invention. Fig. 2 is a schematic diagram showing a cross section parallel to the cell extending direction of one embodiment of the honeycomb structure of the present invention. FIG. 3 is a schematic view showing a cross section perpendicular to the cell extending direction of one embodiment of the honeycomb structure of the present invention. In FIG. 3, the partition walls are omitted.

In the honeycomb structure 100 of the present embodiment, it is only necessary that at least a part of the pair of electrode portions 21 and 21 is made of “TaSi ₂ -containing composite material”. For example, when one electrode part of the pair of electrode parts 21 and 21 is a “first electrode part” and the other electrode part of the pair of electrode parts 21 and 21 is a “second electrode part”, the first electrode part At least one of the part and the second electrode part may be composed of “TaSi ₂ -containing composite material”. Also, part of the first electrode portion, or the portion of the second electrode section may be constituted by "TaSi ₂ containing composite material".

In the honeycomb structure 100 of the present embodiment, the TaSi ₂ -containing composite material that constitutes at least a part of the electrode portion 21 may further contain silicon carbide. That is, the TaSi ₂ -containing composite material may be a composite material containing at least TaSi ₂ , silicon, and silicon carbide. By comprising in this way, it becomes possible to reduce the electrical resistivity of the electrode part 21 favorably.

Here, a part of the pair of electrode portions, in a case which is composed of TaSi ₂ containing composite material, TaSi ₂ containing electrode portions of the other parts other than a part made of a composite material, for example, TaSi ₂ In addition to the contained composite material, a conductive ceramic or metal, specifically, a material containing at least one of silicon carbide and silicon, a material containing a metal silicide, and a material containing at least one of Ni and Cr can be given.

Thermal expansion coefficient of the electrode portion is preferably ^{5.0~8.0 × 10 -6 (/ K)} , more preferably in a 5.5~8.0 × ¹⁰ -6 (/ K) , 6.0 to 8.0 × 10 ⁻⁶ (/ K) is particularly preferable. When the thermal expansion coefficient of the electrode part is 5.0 to 8.0 × 10 ⁻⁶ (/ K) or less, the thermal expansion coefficient is slightly higher than that of the honeycomb structure part. The thermal expansion of the structure portion and the electrode portion is almost equal, and there is an advantage that the thermal shock resistance is improved. For example, if the thermal expansion coefficient of the electrode part is less than 5.0 × 10 ⁻⁶ (/ K), a difference occurs in the thermal expansion between the honeycomb structure part and the electrode part when high-temperature exhaust gas flows in, which is not preferable. . Further, even when the thermal expansion coefficient of the electrode portion is more than 8.0 × 10 ⁻⁶ (/ K), it is not preferable because a difference occurs in the thermal expansion between the honeycomb structure portion and the electrode portion.

  The thermal expansion coefficient of an electrode part means the thermal expansion coefficient in 25-800 degreeC. In this specification, unless otherwise specified, the thermal expansion coefficient is a thermal expansion coefficient at 25 to 800 ° C. The thermal expansion coefficient of the electrode part can be measured by the following method. First, a measurement sample (measurement sample for electrode part) measuring 0.2 mm long × 4 mm wide × 50 mm long is prepared from the electrode part. Hereinafter, the direction from one end to the other end of the part where the length of each measurement sample is 50 mm may be referred to as “the length direction of the measurement sample”. The measurement sample is produced by cutting out from the electrode part of the honeycomb structure so that the cell extending direction of the honeycomb structure is the length direction of the measurement sample. Specifically, the direction (length direction) in which the length of the measurement sample is 50 mm corresponds to the cell extending direction of the honeycomb structure. A direction (lateral direction) of 4 mm in the measurement sample corresponds to the circumferential direction of the side surface of the honeycomb structure. A direction (longitudinal direction) of 0.2 mm in length of the measurement sample corresponds to a direction from the side surface of the honeycomb structure to the inside. If the electrode part is smaller than the measurement sample size described above (length 0.2 mm x width 4 mm x length 50 mm) and the electrode part measurement sample cannot be collected, a smaller measurement sample is prepared and the thermal expansion coefficient is measured. It is a measurement sample for this purpose. If it is smaller and difficult to distinguish from the honeycomb structure part, measure the coefficient of thermal expansion of the outer peripheral wall of the honeycomb structure part. The thermal expansion coefficient of the measurement sample is calculated from the thermal expansion coefficient of the wall. When it is difficult to collect a measurement sample due to the size and shape of the electrode part of the honeycomb structure, a test piece may be made of the same material as the electrode part and used for measurement of the thermal expansion coefficient. . About the produced measurement part for electrode parts, the linear thermal expansion coefficient of 25-800 degreeC is measured by the method based on JISR1618. The linear thermal expansion coefficient of 25 to 800 ° C. is measured in the length direction of each measurement sample. As the thermal dilatometer, “TD5000S (trade name)” manufactured by Bruker AXS can be used. The thermal expansion coefficient of the electrode portion measurement sample measured by the above method is “the thermal expansion coefficient of the electrode portion of 25 to 800 ° C.”.

  The electrical resistivity of the electrode portion means the electrical resistivity at 25 ° C. In this specification, the electrical resistivity of the electrode part is an electrical resistivity at 25 ° C. unless otherwise specified. The electrical resistivity of the electrode part can be measured by the following method. First, from the electrode part, a measurement sample (measurement sample for electrode part) measuring 0.2 mm long × 4 mm wide × 40 mm long is prepared. Next, a silver paste is applied to the entire surface of both ends of the measurement sample, and wiring is performed so that current can be supplied. Next, a voltage application current measuring device is connected to the measurement sample, and a voltage is applied to the measurement sample. 10 to 200 V is applied, the current value and the voltage value in a state of 25 ° C. are measured, and the electrical resistivity is calculated from the obtained current value and voltage value and the measurement sample size. Further, when the electrode part is smaller than the size of the measurement sample described above (length 0.2 mm × width 4 mm × length 40 mm) and the measurement sample cannot be collected, a smaller measurement sample is prepared and the electrical resistivity is measured. A measurement sample for this purpose. If it is smaller and difficult to distinguish from the honeycomb structure part, the electrical resistivity is measured for the outer peripheral wall of the honeycomb structure part, the ratio of the thickness of the outer peripheral wall of the measurement sample and the honeycomb structure part, and the outer periphery of the honeycomb structure part. The electrical resistivity of the measurement sample is calculated from the electrical resistivity of the wall. When it is difficult to collect a measurement sample due to the size and shape of the electrode part of the honeycomb structure, a test piece may be made of the same material as the electrode part and used for measurement of electrical resistivity.

  The electrical resistivity of the electrode part is preferably 0.001 to 10.0 Ωcm, more preferably 0.001 to 2 Ωcm, and particularly preferably 0.001 to 0.1 Ωcm. The electrical resistivity of the electrode part is a value at 25 ° C. When the electric resistivity of the electrode part is 0.001 to 10.0 Ωcm, there is an advantage that the honeycomb structure part can be heated uniformly. For example, if the electrical resistivity of the electrode portion is less than 0.001 Ωcm, it is not preferable in that heat generation near both ends of the electrode portion becomes strong. Moreover, since it becomes difficult for an electric current to flow that the electrical resistivity of an electrode part exceeds 10.0 ohm-cm, it is unpreferable at the point which does not play the role as an electrode.

  The strength of the electrode part (4-point bending strength) is preferably 5 to 30 MPa, more preferably 10 to 30 MPa, and particularly preferably 15 to 30 MPa. For example, if the strength of the electrode portion is less than 5 MPa, it is not preferable because it breaks from the electrode portion when the high temperature exhaust gas flows. The strength of the electrode part can be measured by the following method. First, a measurement sample (electrode portion sample) measuring 0.2 mm long × 4 mm wide × 40 mm long is prepared from the electrode portion. Using such a measurement sample, the 4-point bending strength at room temperature is measured. The 4-point bending strength can be measured according to JIS R 1601. In addition, when the electrode part is smaller than the size of the measurement sample described above (length 0.2 mm × width 4 mm × length 40 mm) and the measurement sample cannot be collected, a smaller measurement sample is prepared and the four-point bending strength is measured. It is a measurement sample for this purpose. If it is smaller and difficult to distinguish from the honeycomb structure part, the four-point bending strength is measured for each outer peripheral wall of the honeycomb structure part, and the ratio of the thickness of the outer peripheral wall of the measurement sample and the honeycomb structure part is determined. From the 4-point bending strength of the outer peripheral wall, the 4-point bending strength of the measurement sample is calculated. If it is difficult to collect a measurement sample due to the size and shape of the electrode part of the honeycomb structure, a test piece may be made of the same material as that of the electrode part and used for measurement of four-point bending strength.

The content ratio (volume ratio) of TaSi _{2 in} the TaSi ₂ -containing composite material is preferably 15 to 78% by volume, more preferably 31 to 78% by volume, and 37 to 78% by volume. It is particularly preferred. When the content ratio of TaSi ₂ is less than 15% by volume, it is not preferable in that the effect of improving the thermal shock resistance due to the high thermal expansion coefficient cannot be obtained. When the content ratio of TaSi ₂ is more than 78% by volume, it is not preferable in that the difference in thermal expansion from the honeycomb structure portion becomes too large.

The content ratio (volume ratio) of silicon in the TaSi ₂ -containing composite material is preferably 5 to 43% by volume, and more preferably 15 to 43% by volume. When the content ratio of silicon is less than 5% by volume, the TaSi ₂ -containing composite material is pulverized in the oxidation treatment step, which is not preferable in that the thermal shock resistance is lowered. When the content ratio of silicon is more than 43% by volume, it is not preferable in the TaSi ₂ -containing composite material that granular Si precipitates on the surface of the TaSi ₂ -containing composite material and does not become a uniform material.

In the case where TaSi ₂ containing composite carbide in is further included, the content ratio of silicon carbide TaSi ₂ containing the composite material (volume ratio) is preferable than 57.5% by volume. The content ratio of silicon carbide is too large, the content ratio of TaSi ₂ and silicon will be relatively reduced.

The content ratio of TaSi ₂ , silicon, and silicon carbide in the TaSi ₂ -containing composite material can be measured from an image obtained by imaging the cross section of the electrode portion of the honeycomb structure with a scanning electron microscope (SEM). . About the cross section of an electrode part, the unevenness | corrugation of a cross section is filled with resin, it grind | polishes further, and the grinding | polishing surface is observed. The polished surface can be observed by energy dispersive X-ray analysis (EDX analysis). Discrimination between TaSi ₂ , silicon, and silicon carbide is performed as follows. The position where the carbon element and the silicon element are detected by energy dispersive X-ray analysis (EDX analysis) is determined as “silicon carbide”. Further, the position where the silicon element is detected without detecting the carbon element is determined as “silicon”. Further, when Ta element is detected by EDX analysis, it is confirmed that all Ta components of the detected Ta element are TaSi ₂ , and the position where Ta element is detected is determined as “TaSi ₂ ”. To do. Then, the SEM is observed so that the three components are shaded. From the observation results of six fields of view (magnification 200 times), the ratio of the three components is measured by image processing software, and the occupation ratio (area%) of TaSi ₂ , silicon carbide, and silicon in the SEM image is obtained. The volume ratio (volume%) of each component of “TaSi ₂ ”, “silicon” and “silicon carbide” is used. ImagePro (manufactured by Nippon Visual Science Co., Ltd.) can be used as image processing software. Moreover, the ratio (mass%) of the mass of each component is the ratio (volume%) and density (TaSi2: 9.1 g / cc, silicon) of each component of “TaSi ₂ ”, “silicon” and “silicon carbide”. : 2.32 g / cc, SiC: 3.2 g / cc).

A preferred embodiment of the TaSi ₂ -containing composite material is a state in which particles made of TaSi ₂ are connected and connected in silicon (Si). For example, in this embodiment, TaSi ₂ exists as particles (TaSi ₂ particles), and silicon functions as a binder that bonds the TaSi ₂ particles together.

  There is no particular limitation on the thickness of the electrode part. For example, the thickness of the electrode part is preferably 50 to 500 μm, more preferably 100 to 300 μm, and particularly preferably 100 to 250 μm. When the thickness of the electrode part is 50 to 500 μm, the honeycomb structure part is likely to generate heat uniformly, and the thermal shock resistance of the electrode part is also good. For example, if the thickness of the electrode part is less than 50 μm, the electrode part may be too thin and it may be difficult to generate heat uniformly in the honeycomb structure part. On the other hand, if the thickness of the electrode part exceeds 500 μm, cracks are likely to occur in the outer wall of the honeycomb structure near the electrode part, and the thermal shock resistance may be lowered. The thickness of the electrode portion can be measured from an image obtained by imaging a cross section perpendicular to the cell extending direction of the honeycomb structure with a scanning electron microscope (SEM).

  The porosity of the electrode part is preferably 30 to 60%, more preferably 30 to 55%, and particularly preferably 35 to 45%. The porosity of the electrode part is a value measured by image processing software by observing a cross section of the electrode part with an SEM. ImagePro (manufactured by Nippon Visual Science Co., Ltd.) can be used as image processing software. Specifically, for example, first, a sample for observing the “cross section” is cut out from the electrode portion. About the cross section of an electrode part, the unevenness | corrugation of a cross section is filled with resin, it grind | polishes further, and the grinding | polishing surface is observed. And the total area of the pore part with respect to the whole is produced from the observation result of “cross section” 2 visual fields (magnification 500 times). When the porosity of the electrode portion is within such a range, the thermal shock resistance is excellent and the electrical resistivity of the electrode portion is also reduced. When the porosity of the electrode part is less than 30%, the heat capacity of the electrode part increases, and the thermal shock resistance may decrease. When the porosity of the electrode portion exceeds 60%, the electrical resistivity of the electrode portion is difficult to decrease.

  As shown in FIGS. 1 to 3, in the honeycomb structure 100 of the present embodiment, each of the pair of electrode portions 21 and 21 is formed in a strip shape extending in the extending direction of the cells 2 of the honeycomb structure portion 4. It is preferable. In a cross section orthogonal to the extending direction of the cell 2, 0.5 times the central angle α of each of the electrode portions 21 and 21 (angle θ which is 0.5 times the central angle α) is 15 to 65 °. Preferably, the angle is 30 to 60 °. With this configuration, it is possible to more effectively suppress the bias of the current flowing in the honeycomb structure portion 4 when a voltage is applied between the pair of electrode portions 21 and 21. That is, the current flowing through the honeycomb structure portion 4 can be made to flow more uniformly. Thereby, the bias of the heat generation in the honeycomb structure part 4 can be suppressed. As shown in FIG. 3, “the central angle α of the electrode portion 21” is two lines connecting the both ends of the electrode portion 21 and the center O of the honeycomb structure portion 4 in a cross section orthogonal to the extending direction of the cell 2. There is an angle formed by minutes. In other words, “the central angle α of the electrode part 21” is “the electrode part 21”, “the line segment connecting one end part of the electrode part 21 and the center O”, and “the other part of the electrode part 21”. This is the inner angle of the portion of the center O in the shape (for example, a fan shape) formed by the “line segment connecting the end and the center O”.

  In addition, “an angle θ that is 0.5 times the central angle α” of one electrode portion 21 is 0.8 to The size is preferably 1.2 times, and more preferably 1.0 times the size (the same size). Thereby, when a voltage is applied between the pair of electrode portions 21 and 21, the bias of the current flowing in the honeycomb structure portion 4 can be more effectively suppressed, and thereby heat generation in the honeycomb structure portion 4 can be suppressed. The bias can be more effectively suppressed.

  In the honeycomb structure 100 shown in FIGS. 1 to 3, each of the pair of electrode portions 21 and 21 is formed to extend in the cell extending direction of the honeycomb structure portion 4. In the honeycomb structure 100, each of the pair of electrode portions 21 and 21 may be formed in a strip shape “between both ends” in the cell extending direction of the honeycomb structure portion 4. As described above, the pair of electrode portions 21 and 21 are disposed so as to extend between both ends of the honeycomb structure portion 4, so that when a voltage is applied between the pair of electrode portions 21 and 21, the honeycomb structure The bias of the current flowing through the portion 4 can be more effectively suppressed. And in the honeycomb structure 100 configured as described above, it is possible to more effectively suppress the deviation of heat generation in the honeycomb structure portion 4. Here, “the electrode portion 21 is formed (arranged) so as to extend between both end portions of the honeycomb structure portion 4” means the following state. That is, one end portion of the electrode portion 21 is in contact with one end portion (one end surface) of the honeycomb structure portion 4, and the other end portion of the electrode portion 21 is the other end portion (the other end surface) of the honeycomb structure portion 4. ).

  Here, another aspect of the electrode portion of the honeycomb structure of the present embodiment will be described. In the honeycomb structure of the present embodiment, the both end portions of the electrode portion in the “cell extending direction of the honeycomb structure portion” are not in contact (not reached) with the first end surface and the second end surface of the honeycomb structure portion. Is also a preferred embodiment. For example, as shown in FIGS. 4 and 5, both end portions 21a and 21b of the electrode portion 21 in the “extending direction of the cells 2 of the honeycomb structure portion 4” are both end portions (first end face 11 and The second end face 12) may not be in contact (not reached). FIG. 4 is a perspective view schematically showing another embodiment (honeycomb structure 200) of the honeycomb structure of the present invention. FIG. 5 is a schematic view showing a cross section of another embodiment (honeycomb structure 200) of the present invention parallel to the cell extending direction. In the honeycomb structure 200 shown in FIGS. 4 and 5, the same components as those in the honeycomb structure 100 shown in FIGS. 1 to 3 are denoted by the same reference numerals and description thereof is omitted. In addition, one end portion of the electrode portion 21 is in contact with (reaches), for example, the first end surface 11 of the honeycomb structure portion 4, and the other end portion of the electrode portion 21 is in contact with the second end surface 12 of the honeycomb structure portion 4. A state of not contacting (not reaching) is also a preferable mode. As described above, when the electrode part 21 has a structure in which at least one end of the electrode part 21 is not in contact with (has reached) either the first end face 11 or the second end face 12 of the honeycomb structure part 4, Thermal shock resistance can be improved. That is, each of the pair of electrode portions 21 and 21 has at least one end portion of the first end surface 11 or the second end surface of the honeycomb structure portion 4 from the viewpoint of “improving the thermal shock resistance of the honeycomb structure”. A structure that is not in contact with (has reached) 12 is preferable. From the above, when emphasizing the viewpoint of “more effectively suppressing the bias of heat generation by effectively suppressing the bias of current in the honeycomb structure portion 4”, the pair of electrode portions 21, It is preferable that 21 is formed so as to extend between both end portions of the honeycomb structure portion 4. On the other hand, when emphasizing the viewpoint of “improving the thermal shock resistance of the honeycomb structure”, at least one end portion of each of the pair of electrode portions 21 and 21 is the first end surface 11 of the honeycomb structure portion 4 or It is preferable that the second end face 12 is not touched (not reached).

  In the honeycomb structure 100 shown in FIGS. 1 to 3, the electrode portion 21 has a shape in which a planar rectangular member is curved along a cylindrical outer periphery. Here, the shape when the curved electrode portion 21 is deformed so as to be a flat member that is not curved is referred to as a “planar shape” of the electrode portion 21. The “planar shape” of the electrode portion 21 shown in FIGS. 1 to 3 is a rectangle. And “the outer peripheral shape of the electrode part” means “the outer peripheral shape in the planar shape of the electrode part”.

  As shown in FIGS. 1 to 3, the outer peripheral shape of the band-shaped electrode portion 21 may be rectangular, but the outer peripheral shape of the band-shaped electrode portion 21 is “a shape in which rectangular corners are formed in a curved shape. Is also a preferred embodiment. Moreover, it is also a preferable aspect that the outer peripheral shape of the strip-shaped electrode portion 21 is “a shape in which rectangular corner portions are linearly chamfered”. A combined application of “curved” and “linear” is also preferred. “Curve” and “straight” combined application means, for example, that in a rectangle, at least one corner is “curved” and at least one corner is “straight” It means a shape that is a “chamfered shape”.

  The outer peripheral shape of the electrode part 21 is “a shape in which rectangular corners are formed in a curved shape” or “a shape in which rectangular corners are chamfered in a straight line”. The property can be further improved. When the corner portion of the electrode portion 21 is a right angle, the stress in the vicinity of the “corner portion of the electrode portion 21” in the honeycomb structure portion 4 tends to be relatively higher than the other portions. On the other hand, when the corner portion of the electrode portion 21 is curved or is chamfered linearly, the stress in the vicinity of the “corner portion of the electrode portion 21” in the honeycomb structure portion 4 can be reduced.

  As for the honeycomb structure part 4 used in the honeycomb structure 100 of the present embodiment, the honeycomb structure part 4 used in the conventional honeycomb structure that functions as a heater by applying a voltage as well as a catalyst carrier is used. it can. Hereinafter, although the structure of the honeycomb structure part 4 is demonstrated, the honeycomb structure 100 of this embodiment is not restrict | limited to such a honeycomb structure part 4. FIG.

  In the honeycomb structure 100 of the present embodiment, the honeycomb structure 4 is made of a material containing at least one of silicon carbide and silicon. For example, the material of the partition wall 1 and the outer peripheral wall 3 of the honeycomb structure portion 4 is preferably a silicon-silicon carbide composite material or silicon carbide as a main component, and is a silicon-silicon carbide composite material or silicon carbide. Is more preferable. When “the material of the partition wall 1 and the outer peripheral wall 3 is mainly composed of silicon carbide particles and silicon”, the partition wall 1 and the outer peripheral wall 3 are made of silicon carbide particles and silicon (total mass) as a whole. It means containing 90 mass% or more. By using such a material, the electrical resistivity of the honeycomb structure part 4 can be set to 2 to 100 Ωcm. Here, the silicon-silicon carbide composite material contains silicon carbide particles as an aggregate and silicon as a binder for bonding silicon carbide particles, and a plurality of silicon carbide particles are interposed between silicon carbide particles. It is preferable to be bonded by silicon so as to form pores. Silicon carbide is obtained by sintering silicon carbide. The electrical resistivity of the honeycomb structure part 4 is a value at 25 ° C.

  The porosity of the partition walls 1 of the honeycomb structure portion 4 is preferably 30 to 60%, and more preferably 35 to 45%. If the porosity is less than 30%, deformation during firing may increase. When the porosity exceeds 60%, the strength of the honeycomb structure may be lowered. The porosity is a value measured with a mercury porosimeter.

  The average pore diameter of the partition walls 1 of the honeycomb structure portion 4 is preferably 2 to 15 μm, and more preferably 5 to 12 μm. If the average pore diameter is smaller than 2 μm, the electrical resistivity may become too large. If the average pore diameter is larger than 15 μm, the electrical resistivity may be too small. The average pore diameter is a value measured with a mercury porosimeter.

  In the honeycomb structure part 4, the partition wall 1 preferably has a thickness of 50 to 300 μm, and more preferably 100 to 200 μm. By setting the thickness of the partition wall 1 in such a range, even when the honeycomb structure 100 is used as a catalyst carrier and a catalyst is supported, it is possible to suppress an excessive increase in pressure loss when exhaust gas flows. When the thickness of the partition wall 1 is less than 50 μm, the strength of the honeycomb structure 100 may be lowered. When the partition wall 1 is thicker than 300 μm, when the catalyst is supported using the honeycomb structure 100 as a catalyst carrier, pressure loss when exhaust gas flows may increase.

The honeycomb structure portion 4 preferably has a cell density of 40 to 150 cells / cm ² , and more preferably 70 to 100 cells / cm ² . By setting the cell density in such a range, the purification performance of the catalyst can be enhanced while reducing the pressure loss when the exhaust gas is flowed. When the cell density is lower than 40 cells / cm ² , the catalyst supporting area may be reduced. When the cell density is higher than 150 cells / cm ² , when the honeycomb structure 100 is used as a catalyst carrier and a catalyst is supported, the pressure loss when the exhaust gas flows may increase.

  The electrical resistivity of the honeycomb structure part 4 is preferably 1 to 200 Ωcm, and more preferably 10 to 100 Ωcm. When the electrical resistivity is less than 1 Ωcm, for example, when the honeycomb structure 100 is energized by a high-voltage power supply of 200 V or higher (the voltage is not limited to 200 V), an excessive current may flow. When the electrical resistivity is greater than 200 Ωcm, for example, when the honeycomb structure 100 is energized by a high-voltage power supply of 200 V or higher (the voltage is not limited to 200 V), current does not flow easily and heat may not be sufficiently generated. is there. The electrical resistivity of the honeycomb structure part 4 is a value measured by a four-terminal method.

  The electrical resistivity of the electrode portion 21 is preferably lower than the electrical resistivity of the honeycomb structure portion 4, and the electrical resistivity of the electrode portion 21 is 20% or less of the electrical resistivity of the honeycomb structure portion 4. More preferably, it is 0.001 to 10%. By setting the electrical resistivity of the electrode part 21 to 20% or less of the electrical resistivity of the honeycomb structure part 4, the electrode part 21 functions more effectively as an electrode.

  When the material of the honeycomb structure portion 4 is a silicon-silicon carbide composite material, the honeycomb structure portion 4 is preferably configured as follows. Ratio of “mass of silicon” contained in honeycomb structure portion 4 to the total of “mass of silicon carbide particles” contained in honeycomb structure portion 4 and “mass of silicon” contained in honeycomb structure portion 4 Is preferably 10 to 40% by mass, and more preferably 15 to 35% by mass. When this ratio is lower than 10% by mass, the strength of the honeycomb structure may be lowered. If it is higher than 40% by mass, the shape may not be maintained during firing.

The honeycomb structure portion has a porosity of 30 to 60%, an average pore diameter of 2 to 20 μm, a partition wall thickness of 50 to 300 μm, a cell density of 40 to 150 cells / cm ² , and between a pair of electrode portions It is more preferable that the electrical resistance at 2 to 100Ω. The honeycomb structure configured in this way is a catalyst carrier and also functions as a heater by applying a voltage. When the electric resistance between the pair of electrode portions is 2 to 100Ω, the honeycomb structure portion 4 generates heat well by applying a voltage to the honeycomb structure portion 4. In particular, even if an electric current is passed through the honeycomb structure portion 4 using a high voltage power source, an excessive current does not flow through the honeycomb structure portion 4 and can be suitably used as a heater.

  Moreover, it is preferable that the thickness of the outer peripheral wall 3 which comprises the outermost periphery of the honeycomb structure part 4 is 0.1-2 mm. If it is thinner than 0.1 mm, the strength of the honeycomb structure 100 may be lowered. If it is thicker than 2 mm, the area of the partition wall 1 supporting the catalyst may be reduced.

  In the honeycomb structure portion 4, the shape of the cell 2 in the cross section orthogonal to the extending direction of the cell 2 is preferably a square, a hexagon, an octagon, or a combination thereof. The shape of the cell 2 is preferably a square or a hexagon. By making the cell shape in this way, the pressure loss when exhaust gas flows through the honeycomb structure 100 is reduced, and the purification performance of the catalyst is excellent.

There is no restriction | limiting in particular about the whole shape of the honeycomb structure part 4. FIG. Examples of the shape of the honeycomb structure portion 4 include a columnar shape with a circular bottom surface, a columnar shape with an oval bottom surface, and a columnar shape with a polygonal bottom surface (square, pentagon, hexagon, heptagon, octagon, etc.). be able to. The honeycomb structure 4 has a bottom area of preferably 2000 to 20000 mm ² , and more preferably 4000 to 10000 mm ² . Further, the length of the honeycomb structure portion 4 in the central axis direction is preferably 50 to 200 mm, and more preferably 75 to 150 mm.

  The honeycomb structure 100 of the present embodiment preferably supports a catalyst and is used as a catalyst body.

Next, still another embodiment of the honeycomb structure of the present invention will be described. The honeycomb structure of the present embodiment is a honeycomb structure 300 as shown in FIG. The honeycomb structure 300 has an electrical resistivity lower than that of the electrode portion 21 in the above-described embodiment of the honeycomb structure of the present invention (honeycomb structure 100 (see FIGS. 1 to 3)). A conductive material (second electrode portion) is provided on the surface of the electrode portion 21. That is, as shown in FIG. 6, in the honeycomb structure 300, the electrode portion 21 is composed of the first electrode portion 23 and the second electrode portion 24 installed on the surface of the first electrode portion 23. It is preferable that at least one of the first electrode part 23 and the second electrode part 24 is made of a TaSi ₂ composite material. In addition, the second electrode portion 24 shown in FIG. 6 is not installed on the surface of the first electrode portion 23, but is a first electrode portion manufactured with a gap in the middle portion (that is, the first electrode portion divided into two). It is also possible to arrange the electrodes in contact with the first electrode parts divided in two. Except that the electrode part 21 is composed of the first electrode part 23 and the second electrode part 24, it is preferable that the electrode part 21 is configured similarly to the honeycomb structure 100 shown in FIGS. 1 to 3. FIG. 6 is a front view schematically showing still another embodiment of the honeycomb structure of the present invention.

  In the honeycomb structure 300, since the second electrode portion 24 having an electrical resistivity lower than that of the first electrode portion 23 is disposed on the surface of the first electrode portion 23, the second electrode portion By applying a voltage to 24, it becomes possible to flow a current more uniformly through the entire honeycomb structure portion 4.

  Although the shape (peripheral shape) of the second electrode portion 24 is not particularly limited, as shown in FIG. 6, the second electrode portion 24 is a rectangle extending from one end portion 21 a of the electrode portion 21 to the other end portion 21 b of the electrode portion 21. Preferably there is. The second electrode portion 24 may not extend between both end portions of the electrode portion 21. That is, there may be a gap between the end portion of the second electrode portion 24 and the end portion of the first electrode portion 23. The length of the second electrode portion 24 is preferably 50% or more of the length of the first electrode portion 23, more preferably 80% or more, and particularly preferably 100%. If the length of the second electrode portion 24 is shorter than 50%, the effect of flowing a current more uniformly through the entire honeycomb structure portion may be reduced when a voltage is applied. The length of the second electrode portion 24 and the length of the first electrode portion 23 are the lengths in the extending direction of the “cells of the honeycomb structure portion”.

In the honeycomb structure 300, the second electrode portion 24 is preferably made of the TaSi ₂ -containing composite material described so far. By comprising in this way, it becomes possible to flow an electric current more uniformly to the whole honeycomb structure part 4. FIG.

  Further, the length in the circumferential direction of the second electrode portion 24 (the circumferential direction on the outer periphery (side surface) of the honeycomb structure portion) may be a length equal to or shorter than the length in the circumferential direction of the first electrode portion 23. Here, the “circumferential direction” means the circumferential direction on the outer periphery (side surface) of the honeycomb structure portion. The circumferential length of the second electrode part 24 is preferably 5 to 75% of the circumferential length of the first electrode part 23, and more preferably 10 to 60%. If it is longer than 75%, the temperature of the honeycomb structure part 4 in the vicinity of both ends of the first electrode part 23 may easily rise in the cross section orthogonal to the cell extending direction. If it is shorter than 5%, when a voltage is applied, the effect of flowing a current more uniformly over the entire honeycomb structure 4 may be reduced.

  Moreover, 50-500 micrometers is preferable, as for the thickness of the 2nd electrode part 24, 100-300 micrometers is more preferable, and it is especially preferable that it is 100-250 micrometers. If it is thicker than 500 μm, cracks are likely to occur in the first electrode part, and the thermal shock resistance may be reduced. The thermal shock resistance of the honeycomb structure 300 may be reduced. If it is less than 50 μm, the electrode part may be too thin and it may be difficult to uniformly generate heat in the honeycomb structure part.

  Next, still another embodiment of the honeycomb structure of the present invention will be described. The honeycomb structure of the present embodiment is a honeycomb structure 400 as shown in FIGS. In the honeycomb structure 100 of the present invention (see FIGS. 1 to 3), the honeycomb structure 400 is a central portion of each electrode portion 21, 21 in a cross section perpendicular to the cell extending direction, and the cell structure. An electrode terminal protrusion 22 for connecting the electrical wiring is disposed at the center in the extending direction. That is, as shown in FIG. 7 to FIG. 9, in the honeycomb structure 400, the electrode terminal protrusions 22 for connecting the electrical wirings are disposed on the respective electrode portions 21 and 21. The electrode terminal protrusion 22 is a portion for connecting a wiring from a power source in order to apply a voltage between the electrode portions 21 and 21. As described above, the electrode terminal protrusions 22 are disposed in the respective electrode portions 21 and 21, so that when the voltage is applied to the respective electrode portions 21 and 21, the temperature distribution of the honeycomb structure portion 4 is biased. , Can be smaller. FIG. 7 is a front view schematically showing still another embodiment of the honeycomb structure of the present invention. FIG. 8 is a schematic diagram showing the A-A ′ cross section in FIG. 7. FIG. 9 is a side view schematically showing still another embodiment of the honeycomb structure of the present invention.

  The honeycomb structure 400 of the present embodiment is configured in the same manner as the honeycomb structure 100 shown in FIGS. 1 to 3 except that the electrode terminal protrusions 22 are disposed on the respective electrode portions 21 and 21. It is preferable.

  The shape of the electrode terminal protrusion 22 is not particularly limited as long as it can be bonded to the electrode 21 and can be connected to the electrical wiring. For example, as shown in FIGS. 7 to 9, the electrode terminal protrusion 22 preferably has a shape in which a columnar protrusion 22b is disposed on a rectangular plate-like substrate 22a. By adopting such a shape, the electrode terminal protrusion 22 can be firmly bonded to the electrode portion 21 by the substrate 22a, and the electric wiring can be reliably bonded by the protrusion 22b.

In the honeycomb structure 400, the electrode terminal protrusion 22 is preferably made of the TaSi ₂ -containing composite material described so far. In particular, the substrate 22a constituting the electrode terminal protrusion 22 is preferably made of the TaSi ₂ -containing composite material described so far. By comprising in this way, it becomes possible to flow an electric current more uniformly to the whole honeycomb structure part 4. FIG.

  In the electrode terminal protrusion 22, the thickness of the substrate 22a is preferably 0.05 to 2 mm. By setting it as such thickness, the electrode terminal protrusion part 22 can be joined to the electrode part 21 reliably. If the thickness is less than 0.05 mm, the substrate 22a becomes weak, and the protrusion 22b may be easily detached from the substrate 22a. If it is thicker than 2 mm, the space for arranging the honeycomb structure may become larger than necessary.

(2) Manufacturing method of honeycomb structure:
Next, an embodiment of a method for manufacturing a honeycomb structure of the present invention will be described. The method for manufacturing a honeycomb structure of the present embodiment includes an electrode part forming step for forming a pair of electrode parts. In the electrode part forming step, first, electrode part forming raw materials are respectively applied to the columnar honeycomb formed body or the first region and the second region of the side surface of the honeycomb fired body obtained by firing the honeycomb formed body. Work. Next, the applied electrode part forming raw material is dried and fired to form a pair of electrode parts. The columnar honeycomb molded body includes a partition wall that partitions and forms a plurality of cells extending from a first end surface that is one end surface serving as a fluid flow path to a second end surface that is the other end surface, and an outer peripheral wall positioned at the outermost periphery. It is what has. A method for manufacturing the columnar honeycomb formed body will be described later.

In this electrode portion forming step, the electrode region forming raw material is formed in the honeycomb molded body or the honeycomb fired body in a cross section perpendicular to the cell extending direction. It coats so that it may be located on the opposite side across the center of the honeycomb fired body. Then, in the method for manufacturing a honeycomb structure of the present embodiment, as the electrode portion forming raw material, using at least containing raw material TaSi ₂ powder and silicon powder. By performing an electrode part formation process using such an electrode part forming raw material, the honeycomb structure 100 as shown in FIGS. 1 to 3 described so far can be easily manufactured.

In the method for manufacturing a honeycomb structured body of the present embodiment, a raw material further containing silicon carbide powder may be used as the electrode part forming raw material. That is, a raw material containing TaSi ₂ , silicon, and silicon carbide powder may be used as the electrode part forming raw material.

In the electrode part forming step, it is preferable to use a powder having an average particle diameter of 3 to 20 μm as the TaSi ₂ powder contained in the electrode part forming raw material. When the average particle size of the TaSi ₂ powder is less than 3 μm, it tends to be easily pulverized in the oxidation treatment step. Further, when the average particle diameter of the TaSi ₂ powder is more than 20 μm, TaSi ₂ is not connected to each other and tends to have high resistance. The average particle diameter of various powders contained in the electrode part forming raw material is a value measured by a laser diffraction method.

In the electrode part forming step, it is preferable to use a powder having an average particle diameter of 1 to 35 μm as the silicon powder contained in the electrode part forming raw material. The silicon powder is melted when the electrode part forming raw material is fired, and becomes a binder for bonding the particles of the silicon carbide powder and the TaSi ₂ powder to each other. If the average particle size of the silicon powder is less than 1 μm, the particles tend to aggregate and become inhomogeneous when the electrode material is mixed. Moreover, when the average particle diameter of the silicon powder is more than 35 μm, the porosity tends to be high and the resistance tends to be high.

  In the electrode part forming step, it is preferable to use a powder having an average particle diameter of 3 to 50 μm as the silicon carbide powder contained in the electrode part forming raw material. When the average particle size of the silicon carbide powder is less than 3 μm, the interface tends to increase and the resistance tends to be high. Further, when the average particle diameter of the silicon carbide powder is more than 50 μm, the strength is low and the thermal shock resistance tends to be inferior.

  Hereinafter, the method for manufacturing a honeycomb structure according to the present embodiment will be described in more detail by taking the method for manufacturing the honeycomb structure shown in FIGS. 1 to 3 as an example.

  First, a honeycomb formed body is manufactured by the following method. Silicon powder (silicon), a binder, a surfactant, a pore former, water, and the like are added to silicon carbide powder (silicon carbide) to produce a honeycomb forming raw material. It is preferable that the mass of the silicon powder is 10 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the silicon powder. The average particle diameter of the silicon carbide particles in the silicon carbide powder is preferably 3 to 50 μm, and more preferably 3 to 40 μm. The average particle diameter of the silicon particles (silicon powder) is preferably 1 to 35 μm. The average particle diameter of the silicon carbide particles and the silicon particles is a value measured by a laser diffraction method. The silicon carbide particles are silicon carbide fine particles constituting the silicon carbide powder, and the silicon particles are silicon fine particles constituting the silicon powder. Note that this is a composition of a honeycomb forming raw material when the material of the honeycomb structure part is a silicon-silicon carbide based composite material, and no silicon is added when the material of the honeycomb structure part is silicon carbide. .

  Examples of the binder include methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The content of the binder is preferably 2.0 to 10.0 parts by mass when the total mass of the silicon carbide powder and the silicon powder is 100 parts by mass.

  The water content is preferably 20 to 60 parts by mass when the total mass of the silicon carbide powder and the silicon powder is 100 parts by mass.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type and may be used in combination of 2 or more type. The content of the surfactant is preferably 0.1 to 2.0 parts by mass when the total mass of the silicon carbide powder and the silicon powder is 100 parts by mass.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include graphite, starch, foamed resin, water absorbent resin, and silica gel. The content of the pore former is preferably 0.5 to 10.0 parts by mass when the total mass of the silicon carbide powder and the silicon powder is 100 parts by mass. The average particle diameter of the pore former is preferably 5 to 30 μm. If it is smaller than 5 μm, pores may not be formed sufficiently. If it is larger than 30 μm, the die may be clogged during molding. The average particle diameter of the pore former is a value measured by a laser diffraction method. When the pore former is a water absorbent resin, the average particle diameter of the pore former is the average particle diameter after water absorption.

  Next, the honeycomb forming raw material is kneaded to form a clay. The method for kneading the honeycomb forming raw material to form the clay is not particularly limited, and examples thereof include a method using a kneader, a vacuum kneader or the like.

  Next, the kneaded material is extruded to produce a honeycomb formed body. In extrusion molding, it is preferable to use a die having a desired overall shape, cell shape, partition wall thickness, cell density and the like. As the material of the die, a cemented carbide which does not easily wear is preferable. The honeycomb formed body has a structure having partition walls that form a plurality of cells that serve as fluid flow paths and an outer peripheral wall that is positioned on the outermost periphery.

  The partition wall thickness, cell density, outer peripheral wall thickness, and the like of the honeycomb formed body can be appropriately determined according to the structure of the honeycomb structure of the present invention to be manufactured in consideration of shrinkage during drying and firing.

  Next, it is preferable to dry the obtained honeycomb formed body. The honeycomb formed body after drying may be referred to as “honeycomb dry body”. The drying method is not particularly limited, and examples thereof include an electromagnetic heating method such as microwave heating drying and high-frequency dielectric heating drying, and an external heating method such as hot air drying and superheated steam drying. Among these, the entire molded body can be dried quickly and uniformly without cracks, and after drying a certain amount of moisture with an electromagnetic heating method, the remaining moisture is dried with an external heating method. It is preferable to make it. As drying conditions, it is preferable to remove moisture of 30 to 99% by mass with respect to the amount of moisture before drying by an electromagnetic heating method, and then to make the moisture to 3% by mass or less by an external heating method. As the electromagnetic heating method, dielectric heating drying is preferable, and as the external heating method, hot air drying is preferable.

  When the length in the central axis direction of the honeycomb formed body (honeycomb dried body) is not a desired length, it is preferable to cut both end surfaces (both end portions) to a desired length. The cutting method is not particularly limited, and examples thereof include a method using a circular saw cutting machine.

  In the method for manufacturing a honeycomb structured body of the present embodiment, the honeycomb dried body obtained in this manner may be degreased and fired to produce a honeycomb fired body. However, by performing the electrode part forming step described below on the honeycomb dried body, the degreasing and firing steps can be performed once in the process of manufacturing the honeycomb structure. In the electrode part forming step described below, a method for forming the electrode part without degreasing and firing the obtained honeycomb dried body without changing the honeycomb dried body will be described. At this stage, each condition when degreasing and firing the honeycomb dried body can be performed according to the degreasing and firing conditions described later.

Next, an electrode part forming raw material for forming the electrode part is prepared. For example, it is preferable to add a predetermined additive to TaSi ₂ powder and silicon powder and knead to prepare an electrode part forming raw material. When preparing the electrode part forming raw material, silicon carbide powder may be further added. Hereinafter, TaSi ₂ powder, silicon powder, and silicon carbide powder used as electrode part forming raw materials are collectively referred to as “raw material powder”.

  More specifically, a binder, a humectant, a dispersant, water, and the like are added to the above raw material powder, and the resulting mixture is kneaded to prepare a paste-like electrode part forming raw material. The method of kneading is not particularly limited, and for example, a vertical stirrer can be used.

Examples of the binder include methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, methyl cellulose and hydroxypropoxyl cellulose are preferable. The binder content is preferably 0.1 to 5.0 parts by mass when the total mass of TaSi ₂ powder, silicon powder, and silicon carbide powder is 100 parts by mass. An example of the humectant is glycerin.

As the dispersant, for example, glycerin, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used as a surfactant. These may be used individually by 1 type and may be used in combination of 2 or more type. The content of the surfactant is preferably 0.1 to 10.0 parts by mass when the total mass of TaSi ₂ powder, silicon powder, and silicon carbide powder is 100 parts by mass.

The water content is preferably 15 to 60 parts by mass when the total mass of TaSi ₂ powder, silicon powder and silicon carbide powder is 100 parts by mass.

  Next, it is preferable to apply the obtained electrode part forming raw material to the side surface of the dried honeycomb formed body. Hereinafter, the dried honeycomb formed body may be referred to as “honeycomb dry body”. There is no particular limitation on the method of applying the electrode part forming raw material to the side surface of the dried honeycomb body. For example, a printing method can be mentioned as a method of applying the electrode part forming raw material. In addition, the electrode part forming raw material is preferably applied to the side surface of the honeycomb dried body so as to have the shape of the electrode part in the honeycomb structure described so far. That is, when the region where the electrode part forming raw material is applied is the first region and the second region, the first region is the second region in the cross section perpendicular to the cell extending direction of the honeycomb dried body. It shall be located on the opposite side of the region with respect to the center of the dried honeycomb body. In addition, after the electrode part forming raw material is applied so as to have the shape of the electrode part (for example, a belt shape), for example, the electrode part forming raw material is further applied to the portion for connecting the electric wiring to the electrode part. May be. For example, the electrode part forming raw material may be further applied to the part for connecting the electrical wiring to the electrode part by thermal spraying.

  The thickness of the electrode part can be set to a desired thickness by adjusting the thickness when the electrode part forming raw material is applied. Thus, the electrode part can be formed very easily because the electrode part can be formed by simply applying the electrode part forming raw material to the side surface of the honeycomb dried body, drying and firing. Since the firing process is only required once, it is preferable to apply the electrode part forming raw material to the side surface of the dried honeycomb formed body (honeycomb dry body). However, the dried honeycomb formed body can be fired to prepare the honeycomb fired body first, and the electrode part forming raw material can be applied to the side surface of the honeycomb fired body.

  Next, it is preferable to dry the electrode part forming raw material coated on the side surface of the dried honeycomb body to produce a “honeycomb dried body with electrode part forming raw material”. The drying conditions are preferably 100 to 130 ° C.

  Next, degreasing is preferably performed in order to remove the honeycomb dried body and the binder and the like contained in the electrode part forming raw material coated on the side surface of the honeycomb dried body. Degreasing is preferably performed at 400 to 550 ° C. for 0.5 to 20 hours in an air atmosphere.

  Next, it is preferable to fire the honeycomb dried body with electrode part forming raw material to produce a honeycomb structure. As baking conditions, it is preferable to heat at 1400-1500 degreeC for 1 to 20 hours in inert atmosphere, such as argon. The temperature of the firing conditions in this specification is the temperature of the firing atmosphere.

  Moreover, after baking, it is preferable to perform an oxidation process at 1000-1350 degreeC for 1 to 10 hours for durability improvement. The oxidation treatment means heat treatment in an oxidizing atmosphere. As described above, the honeycomb structure 100 as shown in FIGS. 1 to 3 can be manufactured.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
TaSi ₂ powder, silicon powder, silicon carbide powder, methylcellulose, glycerin, polyacrylic acid-based dispersant, and water were mixed with a rotating and rotating stirrer to prepare an electrode part forming raw material. The TaSi ₂ powder had an average particle size of 7 μm. The silicon powder had an average particle size of 6 μm. The silicon carbide powder had an average particle size of 35 μm.

In Example 1, the TaSi ₂ powder, the silicon powder, and the silicon carbide powder are such that the TaSi ₂ powder is 15.8% by volume, the silicon powder is 37.0% by volume, and the silicon carbide powder is 47.2% by volume. To prepare an electrode part forming raw material. In the column of “TaSi ₂ ” in Table 1, the volume ratio (volume%) and the mass ratio (mass%) of the TaSi ₂ powder are shown. In the column of “Si” in Table 1, the volume ratio (% by volume) and the mass ratio (% by mass) of the silicon powder are shown. In the column of “SiC” in Table 1, the volume ratio (volume%) and the mass ratio (mass%) of the silicon carbide powder are shown.

When the total of TaSi ₂ powder, silicon powder, and silicon carbide powder was 100 parts by mass, methyl cellulose was 0.5 part by mass, glycerin was 10 parts by mass, and water was 38 parts by mass. The average particle diameter of the silicon carbide powder was 52 μm, and the average particle diameter of the metal silicon powder was 6 μm. The average particle diameter of silicon carbide and metal silicon is a value measured by a laser diffraction method. The kneading was performed with a vertical stirrer.

  Moreover, a honeycomb forming raw material for producing a honeycomb structure part was prepared. The honeycomb forming raw material was prepared by mixing 6 kg of 5 μm metal silicon powder, 14 kg of 30 μm silicon carbide powder, 1 kg of cordierite powder, 1.6 kg of methylcellulose, and 8 kg of water, and kneader kneading.

  Next, the obtained honeycomb forming raw material was vacuum-kneaded to obtain a kneaded material, and the obtained kneaded material was extruded into a honeycomb shape to obtain a honeycomb formed body. Next, the obtained honeycomb formed body was dried at 120 ° C. to obtain a dried honeycomb body.

  Next, the electrode part forming raw material prepared in advance was applied to the side surface of the obtained dried honeycomb body and dried at 120 ° C. to obtain a dried honeycomb body with electrode part forming raw material. Next, the dried honeycomb body with electrode part forming raw material was degreased at 550 ° C. for 3 hours in an air atmosphere.

  Next, the dehydrated honeycomb dried body with the electrode part forming raw material was fired and oxidized to prepare a honeycomb structure. Firing was performed in an argon atmosphere at 1450 ° C. for 2 hours. The oxidation treatment was performed in the atmosphere at 1300 ° C. for 1 hour.

The honeycomb structure part of the obtained honeycomb structure had a partition wall thickness of 101.6 μm and a cell density of 93 cells / cm ² . The diameter of the end face of the honeycomb structure part was 100 mm, and the length in the cell extending direction was 100 mm.

  Regarding the electrode part of the honeycomb structure of Example 1, the thermal expansion coefficient, the four-point bending strength, and the electrical resistivity were measured by the following methods. The results are shown in Table 2. Moreover, about the electrode part, the thermal shock resistance, the electricity supply performance, and the external appearance were evaluated by the following methods. The results are shown in Table 2. Further, in the column of “Degreasing and firing” in Table 2, the number of degreasing and firing required for manufacturing the honeycomb structure is shown.

[Thermal expansion coefficient]
In the measurement of the thermal expansion coefficient of the electrode part, first, a measurement sample for measuring the thermal expansion coefficient was cut out from the electrode part of the honeycomb structure manufactured in each example and comparative example. The size of the measurement sample was 0.2 mm long × 4 mm wide × 50 mm long. About the produced measurement sample, the thermal expansion coefficient was measured using "TD5000S (brand name)" by BrukerAXS. The measured value was defined as the thermal expansion coefficient (× 10 ⁻⁶ (1 / K)) of the electrode part.

[4-point bending strength]
In the measurement of the four-point bending strength of the electrode part, first, a measurement sample for measuring the four-point bending strength was cut out from the electrode part of the honeycomb structure produced in each example and comparative example. The size of the measurement sample was 0.2 mm long × 4 mm wide × 40 mm long. The value obtained by measuring the four-point bending strength of the produced measurement sample was defined as the four-point bending strength (MPa) of the electrode part. The 4-point bending strength was performed by a method based on JIS R 1601.

[Electric resistivity]
In the measurement of the electrical resistivity of the electrode part, first, a measurement sample (test piece) for measuring the electrical resistivity was cut out from the electrode part of the honeycomb structure produced in each example and comparative example. . The size of the measurement sample (test piece) was 0.2 mm long × 4 mm wide × 40 mm long. About the produced test piece, silver paste was apply | coated to the whole surface of both ends, and it was made to be able to energize by wiring. A voltage application current measuring device was connected to the test piece and applied. 10-200V was applied, the current value and voltage value in the state of 25 degreeC were measured, and the electrical resistivity was computed from the obtained current value and voltage value, and a test piece dimension.

[Thermal shock resistance]
Conducted heating / cooling test of honeycomb structure using `` propane gas burner tester equipped with metal case housing honeycomb structure and propane gas burner capable of supplying heating gas into the metal case '' did. The heated gas was a combustion gas generated by burning propane gas with a gas burner (propane gas burner). And the thermal shock resistance was evaluated by confirming whether the honeycomb structure was cracked by the heating and cooling test. Specifically, first, the obtained honeycomb structure was housed (canned) in a metal case of a propane gas burner testing machine. Then, gas (combustion gas) heated by a propane gas burner was supplied into the metal case so that it passed through the honeycomb structure. The temperature condition of the heated gas flowing into the metal case (inlet gas temperature condition) was as follows. First, the temperature was raised to a specified temperature in 5 minutes, held at the specified temperature for 10 minutes, then cooled to 100 ° C. in 5 minutes, and held at 100 ° C. for 10 minutes. Such a series of operations of raising temperature, cooling and holding is referred to as “temperature raising and cooling operation”. Thereafter, cracks in the honeycomb structure were confirmed. Then, the above “temperature increase and cooling operation” was repeated while increasing the designated temperature from 825 ° C. by 25 ° C. Based on the following evaluation criteria, the thermal shock resistance of the electrode part was evaluated. In addition, evaluation AA has the best thermal shock resistance, and thermal shock resistance falls in order of evaluation A, evaluation B, and evaluation C.
Evaluation AA: No cracking at a specified temperature of 1000 ° C.
Evaluation A: A specified temperature of 950 ° C. to 975 ° C. with no cracks.
Evaluation B: No cracks occurred at a specified temperature of 900 ° C. to 925 ° C.
Evaluation C: A crack occurred at a specified temperature of 875 ° C. or lower.

[Energization performance]
Based on the following evaluation criteria, the energization performance of the electrode part was evaluated. In the honeycomb structure, the lower the resistance of the electrode portion, the wider the heat generation range of the honeycomb structure portion, and the honeycomb structure portion tends to have a uniform temperature. In the evaluation of the energization performance, the evaluation AA has the highest energization performance, and the energization performance decreases in the order of evaluation A, evaluation B, and evaluation C.
Evaluation AA: The electrode part has an electrical resistivity of 0.1 Ωcm or less and 10% or less with respect to the electrical resistivity of the honeycomb structure part.
Evaluation A: Not corresponding to evaluation AA, the electrode part having an electrical resistivity of more than 0.1 Ωcm and not more than 2.0 Ωcm, and not more than 10% with respect to the electrical resistivity of the honeycomb structure part.
Evaluation B: Not applicable to Evaluation AA and Evaluation A, and the electrical resistivity of the electrode part is more than 2.0 Ωcm and 10.0 Ωcm or less, and 20% or less with respect to the electrical resistivity of the honeycomb structure part. Alternatively, the electrode portion has an electrical resistivity of 2.0 Ωcm or less and more than 10% and 20% or less of the electrical resistivity of the honeycomb structure portion.
Evaluation C: Evaluation AA, Evaluation A, and Evaluation B are not applicable.

[appearance]
The appearance of the electrode part was visually confirmed to evaluate the appearance. First, in the formation of an electrode part, what the electrode part pulverized is described as "pulverization" in an evaluation result. Next, about the electrode part which could be formed without pulverizing, the external appearance was confirmed visually and the presence or absence of the crack was confirmed. The case where no crack occurred was evaluated as “good”. For those with cracks, the evaluation results indicate “cracks”.

(Examples 2 to 10 and 12 to 19)
In Examples 2 to 10 and 12 to 19, except for changing the blending ratio of TaSi ₂ powder, silicon powder, and silicon carbide powder as shown in Table 1, a honeycomb structure was obtained in the same manner as Example 1. Produced.

(Example 11)
In Example 11, the mixing ratio of TaSi ₂ powder, silicon powder, and silicon carbide powder was changed as shown in Table 1 to prepare an electrode part forming raw material. In Example 11, a honeycomb forming raw material for producing a honeycomb structure was prepared in the same manner as in Example 1, and the obtained honeycomb forming raw material was vacuum-kneaded to obtain a clay. The obtained clay was extruded into a honeycomb shape to obtain a honeycomb formed body. Next, the obtained honeycomb formed body was dried at 120 ° C. to obtain a dried honeycomb body.

  In Example 11, the honeycomb dried body was manufactured by degreasing and firing the honeycomb dried body alone without applying the electrode portion forming raw material to the dried honeycomb body. Specifically, the dried honeycomb body was degreased at 550 ° C. for 3 hours in an air atmosphere. In Example 11, an electrode part was formed on the honeycomb fired body using the previously prepared electrode part forming raw material in the same manner as in Example 1 to produce a honeycomb structure.

  With respect to the electrode portions of the honeycomb structures of Examples 2 to 19, the thermal expansion coefficient, the four-point bending strength, and the electrical resistivity were measured in the same manner as in Example 1. The results are shown in Table 2. In addition, the thermal shock resistance, current-carrying performance, and appearance were evaluated in the same manner as in Example 1. The results are shown in Table 2. Further, in the column of “Degreasing and firing” in Table 2, the number of degreasing and firing required for manufacturing the honeycomb structure is shown.

(Comparative Examples 1 and 2)
In Comparative Examples 1 and 2, a honeycomb structure was produced in the same manner as in Example 1 except that the blending ratio of TaSi ₂ powder, silicon powder, and silicon carbide powder was changed as shown in Table 1. In the column of “Degreasing and firing frequency” in Table 2, the number of degreasing and firing times required for manufacturing the honeycomb structure is shown.

(Comparative Example 3)
In Comparative Example 3, in place of TaSi ₂ powder was used to prepare an electrode member forming raw material by using the MoSi ₂ powder. The MoSi ₂ powder had an average particle size of 6 μm. In Comparative Example 3, an electrode part forming raw material was prepared by blending so that the MoSi ₂ powder was 60.0% by volume, the silicon powder was 31.4% by volume, and the silicon carbide powder was 8.6% by volume. The column “MoSi ₂ ” in Table 3 shows the volume ratio (% by volume) and the mass ratio (% by mass) of the MoSi ₂ powder. In the column of “Si” in Table 3, the volume ratio (volume%) and the mass ratio (mass%) of the silicon powder are shown. In the column of “SiC” in Table 3, the volume ratio (volume%) and the mass ratio (mass%) of the silicon carbide powder are shown.

  Further, a honeycomb forming raw material for producing a honeycomb structure part was prepared by the same method as in Example 1, and the obtained honeycomb forming raw material was vacuum-kneaded to obtain a kneaded material. A honeycomb formed body was obtained by extrusion molding into a honeycomb shape. Next, the obtained honeycomb formed body was dried at 120 ° C. to obtain a dried honeycomb body.

In Comparative Example 3, a honeycomb fired body was manufactured by degreasing and firing the honeycomb dried body alone without applying the electrode part forming raw material to the dried honeycomb body. Specifically, the dried honeycomb body was degreased at 550 ° C. for 3 hours in an air atmosphere. The reason why the honeycomb dried body is defatted by such a method is as follows. When the dried honeycomb body coated with the electrode part forming raw material containing MoSi ₂ powder is degreased in an air atmosphere, the electrode part forming raw material (separately In other words, the electrode part) is pulverized and the electrode part cannot be formed.

  The degreased honeycomb dried body was fired in an argon atmosphere at 1450 ° C. for 2 hours to produce a honeycomb fired body.

Next, an electrode part forming raw material prepared in advance was applied to the side surface of the obtained honeycomb fired body and dried at 120 ° C. to obtain a honeycomb fired body with an electrode part forming raw material. Next, the honeycomb fired body with electrode part forming raw material was degreased under reduced pressure at 550 ° C. for 3 hours. The purpose of degreasing in a reduced pressure atmosphere is that the MoSi ₂ powder is oxidized and pulverized in the air atmosphere, making it impossible to form the electrode part.

  Next, the honeycomb fired body with the electrode part forming raw material degreased under reduced pressure was heat-treated in an argon atmosphere at 1450 ° C. for 2 hours, and further oxidized in air at 1300 ° C. for 1 hour to obtain a honeycomb structure. The body was made. In the column of “Degreasing and firing frequency” in Table 2, the number of degreasing and firing times required for manufacturing the honeycomb structure is shown.

(result)
As shown in Table 2, the honeycomb structures of Examples 1 to 19 were both excellent in thermal shock resistance and energization performance. Moreover, the honeycomb structures of Examples 1 to 10 and 12 to 17 were excellent in the appearance of the electrode portion even when the number of times of degreasing and firing was one. In addition, the honeycomb structures of Examples 18 and 19 were confirmed to be slightly powdered on the outermost surface of the electrode portion when the number of times of degreasing and firing was 1, but the actual use of the honeycomb structure was confirmed. However, there was no problem.

On the other hand, in the honeycomb structure of Comparative Example 1, the electrode portion was pulverized in the oxidation treatment process. It is considered that the cause of the powdered electrode part is that silicon cannot cover the TaSi ₂ surface and the TaSi ₂ oxidation protection function by silicon is not expressed. The honeycomb structure of Comparative Example 2 has a low coefficient of thermal expansion and poor thermal shock resistance.

  In addition, the honeycomb structure of Comparative Example 3 was excellent in current-carrying performance, but was inferior in thermal shock resistance as compared with Example 10. Moreover, it was necessary to perform degreasing and baking twice, and the manufacturing process was complicated.

  The honeycomb structure of the present invention can be suitably used as a catalyst carrier for an exhaust gas purifying apparatus that purifies exhaust gas from automobiles.

1: partition wall, 2: cell, 3: outer peripheral wall, 4: honeycomb structure part, 5: side face, 11: first end face, 12: second end face, 21: electrode part, 21a: end part (one of the electrode parts) End), 21b: end (the other end of the electrode), 22: electrode terminal protrusion, 22a: substrate, 22b: protrusion, 23: first electrode, 24: second electrode, 100, 200, 300, 400: honeycomb structure, O: center, α: center angle, θ: angle 0.5 times the center angle.

Claims (22)

A columnar honeycomb structure, and a pair of electrode parts disposed on the side surface of the honeycomb structure,
The honeycomb structure portion has a porous partition wall, and an outer peripheral wall disposed on the outermost periphery,
In the honeycomb structure portion, a plurality of cells extending from the first end surface of the honeycomb structure portion to the second end surface are partitioned by the partition walls,
The honeycomb structure part is made of a material containing at least one of silicon carbide and silicon, and
A honeycomb structure in which at least a part of the pair of electrode portions is made of a composite material containing TaSi ₂ and silicon.   The honeycomb structure according to claim 1, wherein the composite material constituting at least a part of the electrode portion further includes silicon carbide. The honeycomb structure according to claim 1 or 2, wherein the electrode portion has a thermal expansion coefficient of 5.0 to 8.0 x ^10-6 (/ K).   The honeycomb structure according to any one of claims 1 to 3, wherein the electric resistivity of the electrode portion is 0.001 to 10.0 Ωcm.   The honeycomb structure according to any one of claims 1 to 4, wherein the electrode portion has a strength of 5 to 30 MPa. The honeycomb structure portion has a porosity of 30 to 60%, an average pore diameter of 2 to 15 μm, a thickness of the partition wall of 50 to 300 μm, a cell density of 40 to 150 cells / cm ² , and a pair of the above The honeycomb structure according to any one of claims 1 to 5, wherein an electrical resistance between the electrode portions is 2 to 100Ω. The honeycomb structure according to any one of claims 1 to 6, wherein a content ratio of the TaSi _{2 in} the composite material constituting the electrode portion is 15 to 78% by volume.   The honeycomb structure according to any one of claims 1 to 7, wherein a content ratio of the silicon in the composite material constituting the electrode portion is 5 to 43% by volume.   The honeycomb structure according to claim 2, wherein a content ratio of the silicon carbide in the composite material constituting the electrode portion is 57.5% by volume or less. Columnar honeycomb molded body having porous partition walls and an outer peripheral wall disposed on the outermost periphery, or first and second regions on the side surface of the honeycomb fired body obtained by firing the honeycomb molded body In addition, each of the electrode part forming raw material is applied, and the applied electrode part forming raw material is dried and baked to form an electrode part forming step of forming a pair of electrode parts,
In the honeycomb formed body, a plurality of cells extending from the first end surface to the second end surface of the honeycomb formed body are partitioned and formed by the partition walls,
In the electrode part forming step, the first region is compared to the second region in the cross section orthogonal to the cell extending direction of the electrode body forming material or the honeycomb fired body. The coating is performed so as to be positioned on the opposite side across the center of the honeycomb formed body or the honeycomb fired body,
A method for manufacturing a honeycomb structure, wherein a raw material containing at least TaSi ₂ powder and silicon powder is used as the electrode part forming raw material.   The honeycomb structure according to claim 10, wherein the electrode part forming step is a step of applying the electrode part forming raw material to the first region and the second region on the side surface of the honeycomb formed body, respectively. Manufacturing method.   The honeycomb formed body or the honeycomb fired body coated with the electrode part forming raw material is degreased at 400 to 550 ° C. in an air atmosphere before the firing in the electrode part forming step. The manufacturing method of the honeycomb structure as described.   In the electrode part forming step, the honeycomb formed body or the honeycomb fired body coated with the electrode part forming raw material is fired at 1400 to 1500 ° C in an Ar atmosphere. The manufacturing method of the honeycomb structure as described.   14. The fired honeycomb formed body or the honeycomb fired body is oxidized at 1000 to 1350 ° C. in an oxidizing atmosphere after the firing in the electrode portion forming step. 14. A method for manufacturing a honeycomb structure. At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ and silicon, and the content ratio of TaSi _{2 in} the composite material is 15 to 78% by volume. The method for manufacturing a honeycomb structured body according to any one of claims 10 to 14. At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ and silicon, and the silicon content ratio of the composite material is 5 to 43% by volume, The method for manufacturing a honeycomb structured body according to any one of claims 10 to 15.   The method for manufacturing a honeycomb structure according to any one of claims 10 to 16, wherein the raw material further containing silicon carbide powder is used as the electrode part forming raw material. At least a part of the electrode part obtained by firing the electrode part forming raw material is composed of a composite material containing TaSi ₂ , silicon and silicon carbide, and the silicon carbide content ratio of the composite material is 57.5 volumes. The method for manufacturing a honeycomb structure according to claim 17, wherein the honeycomb structure is equal to or less than%. The thermal expansion coefficient of the said electrode part obtained by baking the said electrode part formation raw material is 5.0-8.0 * 10 < ^-6 > (/ K), It is any one of Claims 10-18. Method for manufacturing the honeycomb structure.   The method for manufacturing a honeycomb structure according to any one of claims 10 to 19, wherein an electrical resistivity of the electrode part obtained by firing the electrode part forming raw material is 0.001 to 10.0 Ωcm.   The manufacturing method of the honeycomb structure according to any one of claims 10 to 20, wherein the strength of the electrode part obtained by firing the electrode part forming raw material is 5 to 30 MPa. The honeycomb fired body has a porosity of 30 to 60%, an average pore diameter of 2 to 15 μm, a thickness of the partition wall of 50 to 300 μm, a cell density of 40 to 150 cells / cm ² , and a pair of the above-mentioned honeycomb fired bodies The method for manufacturing a honeycomb structured body according to any one of claims 10 to 21, wherein an electrical resistance between the electrode portions is 2 to 100Ω.

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