JP2011212577A - Honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure that functions as a heater as well as being a catalyst carrier.SOLUTION: The honeycomb structure 100 includes: a cylindrical honeycomb structure part 4 that has a porous partition wall 1 and an outer peripheral wall 3 situated in the outermost circumference and that is composed of a ceramics material containing silicon carbide particles as an aggregate and silicon as a binder for combining the silicon carbide particles; a pair of electrodes 21, 21 arranged on the side face of the honeycomb structure part 4; electrode terminal projections 22, 22 arranged on each surface of the pair of electrodes 21, 21; and metallic terminals 23, 23 made of a metallic material electrically connected to the electrode terminal projection 22. In the honeycomb structure, the pair of electrodes 21, 21 and the electrode terminal projections 22, 22 are made of electrically conductive ceramics material essentially consisting of silicon carbide and silicon. Also, the electrode terminal projection 22 and the metallic terminal 23 are joined in a state electrically connected through a brazing filler metal 24.

Description

  The present invention relates to a honeycomb structure, and more particularly to a honeycomb structure that functions as both a catalyst carrier and a heater.

  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.

  For this reason, a method of raising the temperature of exhaust gas by installing a metal heater upstream of the honeycomb structure on which the catalyst is supported has been studied (for example, see Patent Document 2).

  In addition, a self-heating type diesel particulate filter in which an electrode layer is formed around both ends of the filter main body made of porous conductive ceramics except for the central portion has been proposed (for example, see Patent Document 3). .

Japanese Patent No. 4136319 Japanese Patent No. 2931362 JP 2000-297625 A

  When a heater as shown in Patent Document 2 is mounted on a vehicle and used, a power source used for the electrical system of the vehicle is commonly used, and a power source having a high voltage of, for example, 200V is used. However, since the metal heater has a low electrical resistance, there is a problem in that when a power supply having a high voltage of 200 V is used, an excessive current flows and the power supply circuit may be damaged. In addition, there is a problem that power is wasted because current flows excessively in addition to the heater portion.

  Further, if the heater is made of metal, it is difficult to integrate the heater and the catalyst because it is difficult to support the catalyst even if the heater is processed into a honeycomb structure.

  Further, the particulate filter described in Patent Document 3 is used in a high temperature and corrosive gas atmosphere, and when it is mounted on a vehicle such as an automobile, a severe vibration is always applied during traveling. It is important that the filter body and the electrode layer are firmly connected so that the layer does not peel from the filter body. In the above-mentioned patent document 3, it is described that the electrode layers disposed on both end faces of the filter body are formed of a metal material or a conductive ceramic material.

  Originally, the bonding between the ceramic material and the metal material has a low bonding strength at the bonding surface, and the wettability between the ceramic material and the metal material is low. For example, the electrode layer is formed of the metal material, and the ceramic material In order to ensure electrical connection with the filter body, a special forming method such as physical vapor deposition or chemical vapor deposition is required. However, such a method requires a very complicated manufacturing process and a low manufacturing cost. There was a problem of increasing.

  On the other hand, when the electrode layer is formed of a ceramic material, the filter body and the electrode layer are both ceramic materials, so that the formation of the electrode layer is easier than when a metal material is used. In addition, a metallic terminal for supplying power must be connected separately to the electrode layer made of such a ceramic material, and the ceramic material and the metal material can be easily and sufficiently bonded with sufficient strength. The problem of joining is still not solved.

  In particular, in particulate filters (honeycomb structures) used in an exhaust gas atmosphere discharged from engines such as automobiles, electrical connection excellent in heat resistance, thermal shock resistance, etc. is desired. No method has been proposed for joining a ceramic material and a metal material that satisfies the various characteristics described above.

  In addition, the particulate filter described in Patent Document 3 simply heats the filter main body by energizing the electrodes and improves the regeneration efficiency of the filter, and therefore excludes the center of both end faces of the filter main body. The electrode layer is formed only around the periphery. However, in such a configuration, the filter body cannot be heated to a uniform temperature. For example, when the catalyst is supported on the filter body and used as a catalyst carrier, it is supported. It is extremely difficult to control the filter body at a uniform temperature so that all of the catalyst that has been used works well.

  The present invention has been made in view of the above-described problems, and provides a honeycomb structure that functions as both a catalyst carrier and a heater. In particular, a honeycomb structure in which a component made of a ceramic material constituting the honeycomb structure and a metal terminal portion made of a metal material are electrically joined by a connection method that is simple and excellent in heat resistance and thermal shock resistance. I will provide a.

  In order to solve the above-described problems, the present invention provides the following honeycomb structure.

[1] Silicon carbide particles as an aggregate having a porous partition wall that partitions and forms a plurality of cells extending from one end surface to the other end surface serving as a fluid flow path, and an outer peripheral wall located at the outermost periphery And a cylindrical honeycomb structure part made of a ceramic material containing silicon as a binder for bonding the silicon carbide particles, a pair of electrode parts disposed on the side surface of the honeycomb structure part, and the pair of electrodes Electrode terminal protrusions disposed on respective surfaces of the parts, and metal terminal parts made of a metal material electrically connected to the electrode terminal protrusions, the pair of electrode parts, and the electrode terminals The protrusion is made of a conductive ceramic material mainly composed of silicon carbide and silicon, and the electrode terminal protrusion and the metal terminal are joined in a state of being electrically connected via a brazing material. Honeycomb structure

[2] The electrode terminal protrusion is formed in a convex shape or a concave shape, and the metal terminal portion is a concave shape or a convex shape in which the shape at the joint portion with the electrode terminal protrusion is a complementary shape. The honeycomb structure according to [1], wherein the honeycomb structure is formed.

[3] The electrode terminal protrusion and the metal terminal part have a gap between a convex-shaped tip of a concavo-convex shape which is a complementary shape and a concave recess, and the electrode terminal protrusion and the metal terminal portion The honeycomb structure according to [2], wherein the uneven side surface portion into which the metal terminal portion is fitted is joined in a state of being electrically connected via the brazing material.

[4] The electrode terminal protrusion is formed in a convex shape, the metal terminal portion is formed in a concave shape, and the metal terminal portion has a thickness of a wall portion forming the concave shape. The honeycomb structure according to [2] or [3], which is 0.1 to 5 mm.

[5] The electrode terminal protrusion is formed in a convex shape, the metal terminal portion is formed in a concave shape, and the metal terminal portion has an end surface shape of a wall portion forming the concave shape. The honeycomb structure according to any one of [2] to [4], wherein the honeycomb structure has a tapered shape such that a concave inner peripheral side protrudes.

[6] Any of the above [1] to [5], wherein the brazing material contains at least one metal selected from the group consisting of nickel, chromium, titanium, manganese, iron, copper, and silver. The honeycomb structure according to 1.

[7] The honeycomb structure according to any one of [1] to [6], wherein the metal terminal portion is made of Kovar, stainless steel, or Inconel.

[8] A metal coating is disposed on at least a part of the surface of the electrode terminal projection, and the metal coating on the surface of the electrode terminal projection and the metal terminal are electrically connected via the brazing material. The honeycomb structure according to any one of [1] to [7], wherein the honeycomb structures are joined in a state of being connected.

[9] The honeycomb structure according to any one of [1] to [8], wherein a part of a connection portion between the electrode terminal protrusion and the metal terminal is joined via crystallized glass.

[10] Each of the pair of electrode portions extends in the cell extending direction of the honeycomb structure portion and is formed in a band shape between both end portions, and in the cross section orthogonal to the cell extending direction, the pair of electrode portions Any one of the above [1] to [9], wherein one of the electrode portions is disposed on the opposite side of the center portion of the honeycomb structure portion with respect to the other electrode portion of the pair of electrode portions. A honeycomb structure according to any one of the above.

  In the honeycomb structure of the present invention, since the honeycomb structure portion is made of a ceramic material containing silicon carbide particles as an aggregate and silicon as a binder for bonding the silicon carbide particles, the honeycomb structure portion is arranged on a side surface of the honeycomb structure portion. By passing an electric current between a pair of provided electrode portions, the honeycomb structure portion generates heat, and can be suitably used as a heater.

  In addition, since the electrode portion and the electrode terminal protrusion are made of a conductive ceramic material mainly composed of silicon carbide and silicon, the bonding strength with the honeycomb structure portion is high, and the electrode portion to the side surface of the honeycomb structure portion Can be arranged very simply. Furthermore, the electrode terminal protrusion and the metal terminal are joined in a state of being electrically connected via a brazing material, and the joined portion of the ceramic material and the metal material has excellent heat resistance and high heat resistance. Joined in a state of impact.

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. FIG. 2 is a side view showing a state in which the metal terminal portion is not joined to the electrode terminal protrusion in the honeycomb structure shown in FIG. 1. Fig. 4 is a schematic view showing an A-A 'cross section of the honeycomb structure shown in Fig. 3. FIG. 3 is an enlarged cross-sectional view showing an enlarged electrode terminal protrusion and a metal terminal portion of the honeycomb structure shown in FIG. 2. It is an expanded sectional view which expands and shows the electrode terminal protrusion part and the metal terminal part in the cross section orthogonal to the cell extending direction of other embodiment of the honeycomb structure of this invention. [Fig. 10] Fig. 10 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. [Fig. 10] Fig. 10 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. [Fig. 10] Fig. 10 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. [Fig. 10] Fig. 10 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. Fig. 3 is a schematic diagram showing a state in which an electrode portion is disposed on an outer peripheral wall in a cross section orthogonal to a cell extending direction in an embodiment of a honeycomb structure of the present invention. FIG. 6 is a schematic diagram showing a state in which an electrode portion is disposed on an outer peripheral wall in a cross section orthogonal to a cell extending direction in still another embodiment of a honeycomb structure of the present invention. FIG. 6 is a schematic diagram showing a state in which an electrode portion is disposed on an outer peripheral wall in a cross section orthogonal to a cell extending direction in still another embodiment of a honeycomb structure of the present invention. FIG. 6 is a schematic diagram showing a state in which an electrode portion is disposed on an outer peripheral wall in a cross section orthogonal to a cell extending direction in still another embodiment of a honeycomb structure of the present invention. It is a top view which shows the measuring method of the intensity | strength of an electrode terminal protrusion part, a metal terminal part, and a junction part. It is a top view which shows the measuring method of the resistance value of an electrode terminal protrusion part, a metal terminal part, and a junction part.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and those skilled in the art do not depart from the spirit of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge.

(1) Honeycomb structure:
As shown in FIGS. 1 to 5, one embodiment of the honeycomb structure of the present invention is a porous body that partitions and forms a plurality of cells 2 extending from one end face 11 to the other end face 12 serving as a fluid flow path. 1 and an outer peripheral wall 3 located at the outermost periphery (disposed so as to surround the outer periphery of the entire partition wall 1), and a silicon carbide particle as an aggregate and a bond for bonding the silicon carbide particle A cylindrical honeycomb structure portion 4 made of a ceramic material containing silicon as a material, a pair of electrode portions 21 and 21 disposed on the side surface of the honeycomb structure portion 4, and a pair of electrode portions 21 and 21, respectively. The honeycomb structure 100 includes electrode terminal protrusions 22 and 22 disposed on the surface of the metal terminal and metal terminal parts 23 and 23 made of a metal material electrically connected to the electrode terminal protrusion 22. Here, FIG. 1 is a perspective view schematically showing one embodiment of the honeycomb structure of the present invention, and FIG. 2 shows the cell extension direction of one embodiment of the honeycomb structure of the present invention. It is a schematic diagram which shows a parallel cross section. FIG. 3 is a side view showing a state in which the metal terminal portion is not joined to the electrode terminal protrusion in the honeycomb structure shown in FIG. 1, and FIG. 4 is a side view of the honeycomb structure shown in FIG. It is a schematic diagram which shows A 'cross section. FIG. 5 is an enlarged cross-sectional view showing the electrode terminal protrusion and the metal terminal of the honeycomb structure shown in FIG. 2 in an enlarged manner.

  In the honeycomb structure 100 of the present embodiment, the pair of electrode portions 21 and 21 and the electrode terminal protrusions 22 and 22 are made of a conductive ceramic material mainly composed of silicon carbide and silicon, and the electrodes The terminal protrusion 22 and the metal terminal 23 are joined in a state where they are electrically connected via the brazing material 24.

  In such a honeycomb structure of the present embodiment, the honeycomb structure portion 4 is made of a ceramic material containing silicon carbide particles as an aggregate and silicon as a binder for bonding the silicon carbide particles. When the current flows between the pair of electrode portions 21 and 21 disposed on the side surfaces of the honeycomb structure 4, the honeycomb structure portion 4 generates heat and can be suitably used as a heater. In the honeycomb structure 100 of the present embodiment, a plurality of silicon carbide particles constituting the honeycomb structure portion 4 are bonded by silicon so as to form pores between the silicon carbide particles.

  In addition, since the electrode portion 21 and the electrode terminal protrusion 22 are made of a conductive ceramic material mainly composed of silicon carbide and silicon, the bonding strength with the honeycomb structure portion 4 is high, and the side surface of the honeycomb structure portion 4 The electrode part 21 can be disposed very simply. Furthermore, the electrode terminal protrusion 22 and the metal terminal 23 are joined in a state of being electrically connected via the brazing material 24, and the joined portion between the ceramic material and the metal material has excellent heat resistance, And bonded in a state having high thermal shock resistance.

  In the honeycomb structure 100 of the present embodiment, a pair of electrode portions 21 and 21 are disposed on the side surface of the honeycomb structure portion 4. The electrode terminal protrusions 22 and 22 of the respective electrode portions 21 and 21, and metal terminals Since the parts 23 and 23 are electrically connected via the brazing material 24, when a voltage is applied between the metal terminal parts 23 and 23, the honeycomb structure part 4 becomes a resistor and generates heat.

  Conventionally, when exhaust gas is treated with a catalyst supported on a honeycomb structure, it is necessary to raise the temperature of the catalyst to a predetermined temperature. For example, when starting an engine, the catalyst temperature is low and the exhaust gas is not sufficiently purified. However, in the honeycomb structure of the present embodiment, a voltage can be applied to the honeycomb structure portion to generate heat, so that the honeycomb structure is appropriately set as required regardless of the operating state of the engine. The temperature can be raised to a temperature.

  The electrode terminal protrusion described above is a terminal on the honeycomb structure side for ensuring electrical connection with an electric wiring or the like for applying a voltage to the honeycomb structure, and the electrode terminal protrusion and the wiring from the power source Is electrically connected to the metal terminal portion to which is connected. That is, in order to apply a voltage to a honeycomb structure made of a ceramic material (that is, to energize), a metal material that constitutes wiring and terminals from a power source and a ceramic that constitutes at least a part of the honeycomb structure At least one place (a pair) is required to be joined to the material. In the conventional honeycomb structure, when bonding a ceramic material and a metal material, extremely complicated bonding such as physical vapor deposition or chemical vapor deposition has been required. However, the honeycomb structure of the present embodiment is a ceramic material. Since the electrode terminal protrusions made of and the metal terminal made of a metal material are joined in a state of being electrically connected via a brazing material, excellent heat resistance and high heat resistance can be obtained by a simple method. Bonding with impact has been realized.

  Note that the voltage applied between the pair of electrode parts (in other words, the respective metal terminal parts joined to the electrode terminal protrusions) is appropriately determined depending on the temperature at which the honeycomb structure is heated, the material of the honeycomb structure part, and the like. For example, 50 to 300V is preferable, and 100 to 200V is more preferable. For example, when a power supply with a voltage of 200 V is used in an electric system of an automobile, it is preferable to apply the voltage of 200 V.

  In the honeycomb structure of the present embodiment, the electrode terminal projection is formed in a convex shape or a concave shape, and the metal terminal portion is a concave shape in which the shape at the joint portion with the electrode terminal projection is a complementary shape. It is preferably formed in a shape or a convex shape. 1 to 5 show an example in which the electrode terminal protrusion 22 is formed in a convex shape and the metal terminal portion is formed in a concave shape. In addition, as shown in FIG. 6, the pole terminal protrusion part 22 may be formed in a concave shape, and the metal terminal part may be formed in a convex shape. Here, FIG. 6 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of another embodiment of the honeycomb structure of the present embodiment. .

  As shown in FIG. 7, the electrode terminal protrusion 22 and the metal terminal 23 have a gap 25 between the convex tip of the concavo-convex shape which is a complementary shape and the concave recess, and It is preferable that the electrode terminal protrusion portion 22 and the metal terminal portion 23 are joined together in a state where they are electrically connected via a brazing filler metal 24 at the concave and convex side portions. By constituting in this way, the stress caused by the difference in coefficient of thermal expansion between the electrode terminal protrusion 22 and the metal terminal 23 at a high temperature can be relaxed by the gap 25. Here, FIG. 7 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. is there.

  For example, as shown in FIG. 5, when the electrode terminal protrusion 22 is formed in a convex shape and the metal terminal portion 23 is formed in a concave shape, the metal terminal portion 23 is The thickness of the wall portion forming the concave shape is preferably 0.1 to 5 mm, more preferably 0.2 to 3 mm, and particularly preferably 0.3 to 1 mm. With this configuration, the thermal expansion of the metal terminal portion is reduced, the stress on the convex electrode terminal projection (specifically, the clamping pressure of the electrode terminal projection due to thermal expansion) is reduced, and the high temperature It is possible to effectively prevent breakage of the electrode terminal protrusion and the metal terminal portion and peeling of the joint portion due to the brazing material. In addition, since the thickness of the wall part which forms above-mentioned concave shape changes with the magnitude | sizes of an electrode terminal protrusion part and a metal terminal part, it is not limited to an above-described range.

  Further, in the honeycomb structure of the present embodiment, for example, as illustrated in FIG. 8, the electrode terminal protrusion 22 is formed in a convex shape, and the metal terminal portion 23 is formed in a concave shape, It is preferable that the metal terminal part 23 is a taper shape in which the end surface shape of the wall part which forms a concave shape protrudes the inner peripheral side of a concave shape. By comprising in this way, the compressive and tensile stress in the end surface of the wall part which forms the concave shape of the metal terminal part 23 can be made small. Here, FIG. 8 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. is there.

  For example, as shown in FIG. 5, when the end surface of the wall portion forming the concave shape of the metal terminal portion 23 is flat, the wall portion forming the concave shape and the protruding portion of the convex shape (specifically, , Compressive stress is generated on the surface of the brazing material disposed on the convex protrusion surface), near the tip of the wall portion forming the concave shape (that is, near the tip portion where the end surface of the wall portion is opened), There is a case where a phenomenon in which the compressive stress generated on the joint surface changes to a very large tensile stress may be confirmed. Therefore, as shown in FIG. 8, the end face shape of the wall portion forming the concave shape is tapered so that the inner peripheral side of the concave shape protrudes, thereby reducing the tensile stress in the vicinity of the tip portion. It is possible to effectively prevent the electrode terminal protrusion 22 and the metal terminal portion 23 from being peeled off. For example, the angle of the tapered tip portion (edge) is preferably 10 to 60 °, and more preferably 20 to 50 °. If the angle is less than 10 °, the strength of the tip of the concave wall portion may be reduced. On the other hand, if the angle exceeds 60 °, the effect of reducing the tensile stress may be reduced.

  The brazing material for joining the electrode terminal protrusion and the metal terminal part may contain at least one metal selected from the group consisting of nickel, chromium, titanium, manganese, iron, copper, and silver. preferable. In particular, it is more preferable that the brazing material contains at least two metals selected from the above group. The brazing material configured in this manner has a high strength at the joint portion and can realize a joint with excellent thermal shock resistance, and has a low resistance value at the joint portion, so that a good electrical connection is also possible.

  For example, specific types of brazing materials include brazing materials containing nickel and chromium, brazing materials containing titanium and copper, brazing materials containing manganese and copper, brazing materials containing silver and titanium, iron and Examples thereof include a brazing material containing chromium.

  In addition, such a brazing material may contain (add) a specific element for the purpose of improving heat resistance and reducing the melting point of the brazing material. For example, a brazing material in which silicon (Si), boron (B), or the like is added to a brazing material containing nickel and chromium can improve the heat resistance of the brazing material. Moreover, in order to lower the melting point of the brazing material, phosphorus (P) may be added to the brazing material containing nickel and chromium. When such a brazing material is used, brazing can be performed at 1050 to 1090 ° C. in a vacuum.

  In addition, it is preferable that manganese (Mn), zirconium (Zr), or the like is added to the brazing material containing titanium and copper in order to improve the heat resistance of the brazing material. Such a brazing material can be brazed in vacuum at a temperature of about 1050 ° C.

  Similarly, it is preferable that nickel (Ni) or the like is added to the brazing material containing manganese and copper in order to improve the heat resistance of the brazing material. Such a brazing material can be brazed in a vacuum at 930 to 1090 ° C.

  Moreover, it is preferable that copper (Cu), indium (In), etc. are added to the brazing material containing silver and titanium in order to improve the heat resistance of the brazing material. Such a brazing material can be brazed in a vacuum at 840 to 930 ° C.

  Furthermore, it is preferable that nickel (Ni), silicon (Si), or the like is added to the brazing material containing iron and chromium in order to improve the heat resistance of the brazing material. Further, phosphorus (P) may be added to lower the melting point of the brazing material. When such a brazing material is used, it can be brazed in a vacuum at a temperature of about 1090 ° C.

  The thickness of the layer made of the brazing material (hereinafter also referred to as “brazing material layer”) to be joined to the electrode terminal protrusion and the metal terminal is preferably 30 to 300 μm, and more preferably 40 to 200 μm. Preferably, it is 50-150 micrometers. If the thickness of the brazing material layer is less than 30 μm, the joint may be cracked by thermal cycling, while if it exceeds 300 μm, the mechanical strength of the joint may be reduced.

  In the embodiments described so far, an example in which a part of the electrode terminal protrusion and the metal terminal is joined only by the brazing material has been described. For example, as shown in FIG. A part of the connection portion between the electrode terminal protrusion 22 and the metal terminal portion 23 may be bonded via the crystallized glass 26. In FIG. 9, the electrode terminal protrusion 22 is formed in a concave shape, and the metal terminal portion 23 is formed in a convex shape. An example in which the brazing material 24 is disposed between the recesses and the crystallized glass 26 is disposed between the wall portion forming the concave shape and the side surface of the convex projection is illustrated. Yes. Here, FIG. 9 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. is there.

  By disposing such crystallized glass, the bonding strength can be improved. In addition, there is no restriction | limiting in particular about the arrangement position of crystallized glass, A part of electrode terminal projection part and a metal terminal part are joined by brazing material, and another part is joined by crystallized glass. That's fine. In addition, since the electroconductivity is not ensured, the joining part by crystallized glass is more preferably less than 70% of the area which joins an electrode terminal protrusion part and a metal terminal part.

Specific examples of the crystallized glass material include SiO ₂ and Al ₂ O ₃ . Such crystallized glass is excellent in bonding strength and heat resistance.

  Further, the pair of electrode portions and the electrode terminal protrusions constituting the honeycomb structure of the present embodiment are made of a conductive ceramic material mainly composed of silicon carbide and silicon, and are applied by the metal terminal portions. The honeycomb structure can be heated by the voltage. Here, when the phrase “the pair of electrode portions and the electrode terminal protrusions are mainly composed of silicon carbide and silicon” is used, the pair of electrode portions and the electrode terminal protrusions are composed of silicon carbide and silicon as a whole. It means containing 90 mass% or more. For this reason, a pair of electrode part and electrode terminal protrusion part may be formed only from silicon carbide and silicon, and a trace amount impurity of 10 mass% or less and another ceramic component may contain.

  The electrode portion and the electrode terminal protrusion may be made of a conductive ceramic material having the same ratio of silicon carbide and silicon, or may be made of a conductive ceramic material having a different ratio. Good. In addition, when the component of an electrode part and the component of an electrode terminal protrusion part are the same (or close) component, since the thermal expansion coefficient of an electrode part and an electrode terminal protrusion part becomes the same (or close) value, it is preferable. Further, since the materials are the same (or close), the bonding strength between the electrode portion and the electrode terminal protrusion is also increased. Therefore, even when a thermal stress is applied to the honeycomb structure, it is possible to satisfactorily prevent the electrode terminal protrusion from being peeled off from the electrode part or the joint between the electrode terminal protrusion and the electrode part being damaged. .

  In addition, as shown in FIGS. 1-5, it is preferable that the electrode terminal projection part 22 is comprised by the square-shaped board | substrate 22a and the cylindrical projection part 22b (convex-shaped part). 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 electrode terminal protrusion 22, the thickness of the substrate 22a is preferably 1 to 5 mm. By setting it as such thickness, the electrode terminal protrusion part 22 can be joined to the electrode part 21 reliably. If it is thinner than 1 mm, the substrate 22a becomes weak, and the protrusion 22b may be easily detached from the substrate 22a. If it is thicker than 5 mm, the space for arranging the honeycomb structure may become larger than necessary.

  In the electrode terminal protrusion 22, the length (width) of the substrate 22a in the “circumferential direction R of the honeycomb structure 4” is 20 times the length of the electrode 21 in the “circumferential direction R of the honeycomb structure 4”. It is preferably -100%, and more preferably 30-100%. By setting it as such a range, the electrode terminal protrusion part 22 becomes difficult to remove | deviate from the electrode part 21. FIG. If it is shorter than 20%, the electrode terminal protrusion 22 may be easily detached from the electrode portion 21. In the electrode terminal protrusion 22, the length of the substrate 22 a in the “cell 2 extending direction” is preferably 5 to 30% of the length of the honeycomb structure 4 in the cell extending direction. By setting the length of the substrate 22a in the “direction in which the cells 2 extend” within such a range, sufficient bonding strength can be obtained. If the length of the substrate 22 a in the “cell 2 extending direction” is shorter than 5% of the length of the honeycomb structure portion 4 in the cell extending direction, the substrate 22 a may be easily detached from the electrode portion 21. And if it is longer than 30%, the mass may increase.

  In the electrode terminal protrusion 22, the thickness of the protrusion 22b is preferably 3 to 20 mm. By setting it as such thickness, the projection part 22b and the metal terminal part 23 can be joined more firmly. If it is thinner than 3 mm, the protrusion 22b may be easily broken. If it is thicker than 20 mm, it may be difficult to connect to the metal terminal portion 23. Further, the length of the protrusion 22b is preferably 3 to 20 mm. With such a length, the metal terminal portion 23 can be satisfactorily bonded to the protruding portion 22b. If it is shorter than 3 mm, it may be difficult to join the metal terminal portion 23. If it is longer than 20 mm, the protrusion 22b may be easily broken.

  As shown in FIG. 2, the electrode terminal protrusion 22 is preferably disposed at the center of the electrode portion 21 in the “direction in which the cell 2 extends”. Thereby, it becomes easy to heat the whole honeycomb structure part 4 uniformly.

  The volume electrical resistance at 400 ° C. of the electrode terminal protrusion 22 is preferably 0.1 to 2.0 Ωcm, and more preferably 0.1 to 1.0 Ωcm. By setting the volume electrical resistance of the electrode terminal protrusion 22 at 400 ° C. in such a range, current can be efficiently supplied from the electrode terminal protrusion 22 to the electrode section 21 in a pipe through which high-temperature exhaust gas flows. Can do. If the volume electrical resistance at 400 ° C. of the electrode terminal protrusion 22 is smaller than 0.1 Ωcm, it may be deformed during manufacturing. If the volume electrical resistance at 400 ° C. of the electrode terminal protrusion 22 is larger than 2.0 Ωcm, it may be difficult to supply a current to the electrode portion 21 because the current hardly flows.

  The electrode terminal protrusion 22 preferably has a porosity of 30 to 45%, more preferably 30 to 40%. When the porosity of the electrode terminal protrusion 22 is within such a range, an appropriate volume electric resistance can be obtained. If the porosity of the electrode terminal protrusion 22 is lower than 30%, it may be deformed during manufacture. If the porosity of the electrode terminal protrusion 22 is higher than 45%, the strength of the electrode terminal protrusion 22 may be reduced. In particular, if the strength of the protrusion 22b is reduced, the protrusion 22b may be easily broken. The porosity is a value measured with a mercury porosimeter.

  The electrode terminal protrusion 22 preferably has an average pore diameter of 5 to 20 μm, and more preferably 7 to 15 μm. When the average pore diameter of the electrode terminal protrusion 22 is within such a range, an appropriate volume electric resistance can be obtained. If the average pore diameter of the electrode terminal protrusion 22 is smaller than 5 μm, it may be deformed during manufacture. When the average pore diameter of the electrode terminal protrusion 22 is larger than 20 μm, the strength of the electrode terminal protrusion 22 may be reduced. In particular, when the strength of the protrusion 22b is reduced, the protrusion 22b may be easily broken. The average pore diameter is a value measured with a mercury porosimeter.

  The average particle diameter of the silicon carbide particles contained in the electrode terminal protrusion 22 is preferably 10 to 60 μm, and more preferably 20 to 60 μm. By setting the average particle diameter of the silicon carbide particles contained in the electrode terminal protrusion 22 within such a range, the volume electrical resistance at 400 ° C. of the electrode terminal protrusion 22 is set to 0.1 to 2.0 Ωcm. Can do. If the average pore diameter of the silicon carbide particles contained in the electrode terminal protrusion 22 is smaller than 10 μm, the volume electrical resistance at 400 ° C. of the electrode terminal protrusion 22 may become too large. If the average pore diameter of the silicon carbide particles contained in the electrode terminal protrusion 22 is larger than 60 μm, the volume electrical resistance of the electrode terminal protrusion 22 at 400 ° C. may be too small. The average particle diameter of the silicon carbide particles contained in the electrode terminal protrusion 22 is a value measured by a laser diffraction method.

  It is preferable that the ratio of the mass of silicon contained in the electrode terminal protrusion 22 to the “total mass of silicon carbide and silicon” contained in the electrode terminal protrusion 22 is 20 to 40% by mass, More preferably, it is 25-35 mass%. When the ratio of the mass of silicon to the total mass of silicon carbide and silicon contained in the electrode terminal protrusion 22 is within such a range, an appropriate volume electric resistance can be obtained. When the ratio of the mass of silicon to the total mass of silicon carbide and silicon contained in the electrode terminal protrusion 22 is smaller than 20% by mass, the volume electrical resistance may be excessively increased. And when larger than 40 mass%, it may deform | transform at the time of manufacture.

  In the honeycomb structure 100 of the present embodiment, the electrode terminal protrusion 22 has a porosity of 30 to 45%, the electrode terminal protrusion 22 has an average pore diameter of 5 to 20 μm, and is contained in the electrode terminal protrusion 22. The ratio of the “mass of silicon” contained in the electrode terminal projection 22 to the “total of the respective masses of silicon carbide and silicon” is 20 to 40% by mass, and is contained in the electrode terminal projection 22. It is preferable that the average particle diameter of the silicon carbide particles (silicon carbide particles) is 10 to 60 μm and the volume electric resistance of the electrode terminal protrusion 22 is 0.1 to 2.0 Ωcm. Thereby, in particular, the honeycomb structure can be uniformly energized.

  In addition, the electrical resistance at 400 ° C. of the honeycomb structure 100 of the present embodiment measured at “between the electrode terminal protrusions disposed on each of the pair of electrode portions 21 and 21” is 1 to 20Ω. Is preferable, and it is still more preferable that it is 3-10 (ohm). If the electrical resistance at 400 ° C. is smaller than 1Ω, it is not preferable because an excessive current flows when the honeycomb structure 100 is energized by a 200 V power source. When the electrical resistance at 400 ° C. is greater than 20Ω, it is not preferable because current hardly flows when the honeycomb structure 100 is energized by a 200 V power source. The electrical resistance at 400 ° C. of the honeycomb structure is a value measured by the two-terminal method.

  Further, in the honeycomb structure of the present embodiment, as shown in FIG. 10, a metal coating 27 is disposed on at least a part of the surface of the electrode terminal projection 22, and the metal coating on the surface of the electrode terminal projection 22. 27 and the metal terminal portion 23 may be joined in a state of being electrically connected via the brazing material 24. Here, FIG. 10 is an enlarged cross-sectional view showing, in an enlarged manner, electrode terminal protrusions and metal terminal portions in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present embodiment. is there.

  Such a metal coating can be formed, for example, by disposing a metal coating on the surface of the electrode terminal protrusion 22 by a method such as thermal spraying or vapor deposition. In addition, since the metal film is formed on the electrode terminal protrusions, the metal film can be formed more easily than when the metal film is directly formed on the surface of the honeycomb structure.

  As a specific method for forming the metal coating, for example, there is a method in which silicon (Si) is sprayed on the surface of the electrode terminal protrusion, or a method in which a metal material is vacuum deposited on the surface of the electrode terminal protrusion.

  Moreover, although there is no restriction | limiting in particular about the kind of metal material which comprises a metal terminal part, For example, it is preferable that a low thermal expansion metal is used and the residual stress at normal temperature can be reduced. Specific examples of the metal material include Kovar, stainless steel such as SUS430, Inconel, and the like.

  Moreover, the metal terminal part used for the honeycomb structure of the present embodiment is a terminal for electrical connection with the electrode terminal protrusions described so far, and is formed of a metal material. The shape of the metal terminal portion may be any as long as it can be electrically and physically connected to the electrode terminal protrusion portion described so far via a brazing material.

  Moreover, this metal terminal part can reduce the thermal stress at the time of high temperature also by using a thin metal. That is, as described above, by reducing the thickness of the portion joined via the brazing material of the metal terminal portion (for example, the thickness of the wall portion forming the concave shape of the metal terminal portion 22 in FIG. 2). The amount of thermal expansion of the metal terminal portion at the joint portion can be reduced to effectively prevent breakage of the electrode terminal protrusion and metal terminal portion at high temperatures, and peeling of the joint portion due to the brazing material.

  The metal terminal portion is electrically connected to a power source for applying a voltage to the honeycomb structure by a metal wiring or the like. Since both the metal terminal portion and the metal wiring are metal, low resistance electrical connection is possible by a conventionally known method of joining metals (for example, welding, soldering, etc.).

  If the metal terminal portion has a sufficient bonding strength, a shape in which the bonding area with the ceramic is reduced is applied to improve the peeling of the bonded portion after the thermal cycle.

  The honeycomb structure portion is made of a ceramic material containing silicon carbide particles as an aggregate and silicon as a binder for bonding the silicon carbide particles, and serves as a fluid flow path as shown in FIGS. A porous partition wall 1 defining a plurality of cells 2 extending from one end surface 11 to the other end surface 12, and an outer peripheral wall 3 positioned at the outermost periphery (disposed to surround the entire outer periphery of the partition wall 1); It is what has. Since this honeycomb structure part is composed of silicon carbide particles as an aggregate as described above, and a ceramic material containing silicon as a binder for bonding the silicon carbide particles (that is, a ceramic material having conductivity), When a voltage is applied through the electrode part, the honeycomb structure part acts as a resistor to cause the honeycomb structure to generate heat.

  In the honeycomb structure 100 of the present embodiment, “the mass of silicon carbide particles as an aggregate” contained in the honeycomb structure portion 4 and “the mass of silicon as a binder” contained in the honeycomb structure portion 4 The ratio of “mass of silicon as a binder” contained in the honeycomb structure portion 4 to the total of the above is preferably 10 to 40% by mass, and more preferably 15 to 25% by mass. If it 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 partition wall thickness constituting the honeycomb structure part 4 is preferably 50 to 150 μm, and more preferably 70 to 100 μm. By setting the partition wall thickness 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. If the partition wall thickness is less than 50 μm, the strength of the honeycomb structure may be lowered. When the partition wall thickness is thicker than 150 μm, 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 become too large.

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 , the honeycomb structure 100 is used as a catalyst carrier to support the catalyst. In addition, the pressure loss when the exhaust gas flows may become too large.

  Moreover, the average particle diameter of the silicon carbide particles (aggregate) constituting the honeycomb structure portion 4 is 3 to 30 μm, and preferably 5 to 20 μm. By setting the average particle diameter of the silicon carbide particles constituting the honeycomb structure portion 4 in such a range, the volume electrical resistance at 400 ° C. of the honeycomb structure 100 can be set to 1 to 20 Ωcm. When the average particle diameter of the silicon carbide particles is smaller than 3 μm, the volume electric resistance at 400 ° C. of the honeycomb structure 100 is not preferable. If the average particle diameter of the silicon carbide particles is larger than 30 μm, the volume electrical resistance at 400 ° C. of the honeycomb structure 100 is not preferable. Further, if the average particle diameter of the silicon carbide particles is larger than 30 μm, it is not preferable because the forming raw material may be clogged in the die for extrusion forming when the honeycomb formed body is extruded. The average particle diameter of the silicon carbide particles is a value measured by a laser diffraction method.

  Moreover, the volume electrical resistance at 400 ° C. of the honeycomb structure part 4 is preferably 1 to 20 Ωcm, and more preferably 3 to 10 Ωcm. If the volume electrical resistance at 400 ° C. is less than 1 Ωcm, an excessive current flows when the honeycomb structure 100 is energized by a 200 V power source (the voltage is not limited to 200 V), which is not preferable. When the volume electrical resistance at 400 ° C. is greater than 20 Ωcm, it is preferable that current does not flow easily when the honeycomb structure 100 is energized by a 200 V power source (the voltage is not limited to 200 V), and may not generate sufficient heat. Absent. The volume electrical resistance at 400 ° C. of the honeycomb structure is a value measured by the two-terminal method.

  In the honeycomb structure 100 of the present embodiment, the electrical resistance of the honeycomb structure 100 at 400 ° C. is preferably 1 to 20Ω, and more preferably 3 to 10Ω. If the electrical resistance at 400 ° C. is less than 1Ω, for example, when the honeycomb structure 100 is energized by a 200 V power source (the voltage is not limited to 200 V), an excessive current flows, which is not preferable. When the electrical resistance at 400 ° C. is greater than 20Ω, for example, when the honeycomb structure 100 is energized by a 200 V power source (the voltage is not limited to 200 V), it is not preferable because current hardly flows. The electrical resistance at 400 ° C. of the honeycomb structure is a value measured by the two-terminal method.

  In the honeycomb structure 100 of the present embodiment, the volume electrical resistance at 400 ° C. of the electrode portion 21 is lower than the volume electrical resistance at 400 ° C. of the honeycomb structure portion 4, and the volume of the electrode portion 21 at 400 ° C. The electrical resistance is 20% or less, and preferably 1 to 10%, of the volume electrical resistance at 400 ° C. of the honeycomb structure part 4. By setting the volume electrical resistance of the electrode portion 21 at 400 ° C. to 20% or less of the volume electrical resistance of the honeycomb structure portion 4 at 400 ° C., the electrode portion 21 functions more effectively as an electrode.

  The porosity of the partition wall 1 is preferably 35 to 60%, more preferably 45 to 55%. A porosity of less than 35% is not preferable because deformation during firing increases. If the porosity exceeds 60%, the strength of the honeycomb structure decreases, which is not preferable. The porosity is a value measured with a mercury porosimeter.

  The average pore diameter of the partition wall 1 is preferably 2 to 15 μm, and more preferably 4 to 8 μm. If the average pore diameter is smaller than 2 μm, the volume electrical resistance becomes too large, which is not preferable. If the average pore diameter is larger than 15 μm, the volume electrical resistance becomes too small, which is not preferable. The average pore diameter is a value measured with a mercury porosimeter.

In the honeycomb structure 100 of the present embodiment, the thickness of the partition wall 1 is 70 to 100 μm, the cell density is 70 to 100 cells / cm ² , and the average particle diameter of the silicon carbide particles as the aggregate is 5 to 5. 20 μm, the porosity of the partition wall 1 is 45 to 55%, the average pore diameter of the partition wall 1 is 4 to 8 μm, and the mass of silicon carbide particles as an aggregate contained in the honeycomb structure portion 4 and the binder It is preferable that the ratio of the mass of silicon as a binder to the total mass of silicon as is 15 to 25 mass%, and the volume electric resistance of the honeycomb structure portion 4 at 400 ° C. is 3 to 10 Ωcm. By configuring the honeycomb structure 100 of the present embodiment in this way, there is an advantage that the pressure loss is particularly low when exhaust gas is flowed and the exhaust gas purification performance is excellent.

  Further, in the honeycomb structure 100 of the present embodiment, the partition walls 1 and the outer peripheral wall 3 are preferably composed mainly of silicon carbide particles as an aggregate and silicon as a binder for bonding the silicon carbide particles, It may be formed only from silicon carbide and silicon. Even when the partition wall 1 and the outer peripheral wall 3 are formed only of silicon carbide and silicon, a trace amount of impurities of 10% by mass or less may be contained. When the partition wall 1 and the outer peripheral wall 3 contain a substance (a trace amount of impurities) other than “silicon carbide and silicon”, examples of other substances contained in the partition wall 1 and the outer peripheral wall 3 include silicon oxide and strontium. be able to. Here, when “the partition wall 1 and the outer peripheral wall 3 are mainly composed of silicon carbide particles and silicon”, the partition wall 1 and the outer peripheral wall 3 contain 90% by mass or more of silicon carbide particles and silicon. Means that

  As shown in FIGS. 1 to 4, each of the pair of electrode portions 21 and 21 extends in the cell 2 extension direction of the honeycomb structure portion 4 and extends between both end portions (between both end surfaces 11 and 12). It is preferable to be formed. And in the cross section orthogonal to the extending direction of the cell 2, one electrode portion 21 in the pair of electrode portions 21, 21 is formed of the honeycomb structure portion 4 with respect to the other electrode portion 21 in the pair of electrode portions 21, 21. It is preferable that the central portion O be disposed on the opposite side. Thus, the electrode portion 21 is formed in a strip shape, the longitudinal direction of the strip-shaped electrode portion 21 extends in the direction in which the cells 2 of the honeycomb structure portion 4 extend, and the electrode portion 21 further includes the honeycomb structure portion 4. Since it extends between both end portions (between both end surfaces 11 and 12), the entire honeycomb structure portion 4 can be heated more uniformly. In addition, in the cross section orthogonal to the extending direction of the cell 2, one electrode portion 21 in the pair of electrode portions 21, 21 is formed of the honeycomb structure portion 4 relative to the other electrode portion 21 in the pair of electrode portions 21, 21. By arranging the central portion O on the opposite side across the center portion O, the entire honeycomb structure portion 4 can be heated more evenly.

  The length (width) of the electrode portion 21 in the “circumferential direction R of the honeycomb structure portion 4” is 1/30 to the length of the side surface 5 of the honeycomb structure portion 4 in the circumferential direction R (length of the outer periphery). It is preferably 1/4, and more preferably 1/30 to 1/10. By setting it as such a range, the whole honeycomb structure part 4 can be heated more uniformly. If the length (width) of the electrode portion 21 in the circumferential direction R of the honeycomb structure portion 4 is shorter than 1/30 of the length of the side surface 5 of the honeycomb structure portion 4 in the circumferential direction R, heat cannot be generated uniformly. There is. If it is longer than ¼, the vicinity of the center portion of the honeycomb structure portion 4 may be difficult to be heated.

  The thickness of the electrode portion 21 is preferably 0.2 to 2.0 mm, and more preferably 0.5 to 1.5 mm. By setting it within such a range, heat can be generated uniformly. If the thickness of the electrode part 21 is less than 0.2 mm, the electrical resistance may increase and heat may not be generated uniformly. If it is thicker than 2.0 mm, it may be damaged during canning.

  The electrode part 21 is preferably disposed on the surface of the outer peripheral wall 3 as shown in FIG. 11A. Moreover, the electrode part 21 may be arrange | positioned so that it may be embedded inside the outer peripheral wall 3, as shown to FIG. 11B. Furthermore, as shown in FIG. 11C and FIG. 11D, the electrode part 21 is partially embedded (in the side in contact with the outer peripheral wall) inside the outer peripheral wall 3, and the remaining part (on the front side) It is also a preferable aspect that a part) is out of the outer peripheral wall 3 (to the surface side). FIG. 11C shows an aspect in which the thickness of the portion embedded in the outer peripheral wall 3 of the electrode 21 is thinner than the thickness of the outer peripheral wall 3. FIG. 11D shows a mode in which the thickness of the portion embedded in the outer peripheral wall 3 of the electrode 21 is the same as the thickness of the outer peripheral wall 3.

  Here, FIG. 11A is a schematic view showing a state in which the electrode portion 21 is disposed on the outer peripheral wall 3 in a cross section orthogonal to the cell extending direction of one embodiment of the honeycomb structure of the present invention. FIG. 11B is a schematic view showing a state in which the electrode portion 21 is disposed on the outer peripheral wall 3 in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present invention. FIG. 11C is a schematic diagram showing a state in which the electrode portion 21 is disposed on the outer peripheral wall 3 in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present invention. FIG. 11D is a schematic view showing a state in which the electrode portion 21 is disposed on the outer peripheral wall 3 in a cross section orthogonal to the cell extending direction of still another embodiment of the honeycomb structure of the present invention. 11A to 11D, only a part of the outer peripheral wall 3 and one electrode portion 21 are shown, and the partition walls and the like are not shown.

  The electrode part 21 is mainly composed of silicon carbide and silicon, and the component of the electrode part 21 and the component of the honeycomb structure part 4 are the same (or close) components. Have the same (or close) thermal expansion coefficient. Further, since the materials are the same (or close), the bonding strength between the electrode portion 21 and the honeycomb structure portion 4 is also increased. For this reason, even if thermal stress is applied to the honeycomb structure, it is possible to prevent well that the electrode portion 21 is peeled off from the honeycomb structure portion 4 and the joint portion between the electrode portion 21 and the honeycomb structure portion 4 is damaged. Can do.

  The volume electric resistance of the electrode portion 21 at 400 ° C. is preferably 0.1 to 2.0 Ωcm, and more preferably 0.1 to 1.0 Ωcm. By setting the volume electrical resistance of the electrode portion 21 at 400 ° C. in such a range, the pair of electrode portions 21 and 21 effectively serve as electrodes in the pipe through which high-temperature exhaust gas flows. If the volume electrical resistance at 400 ° C. of the electrode portion 21 is smaller than 0.1 Ωcm, it may be deformed during manufacturing. If the volume electrical resistance of the electrode portion 21 at 400 ° C. is larger than 2.0 Ωcm, it may be difficult to play a role as an electrode because current hardly flows.

  The electrode part 21 preferably has a porosity of 30 to 45%, more preferably 30 to 40%. When the porosity of the electrode portion 21 is within such a range, a suitable volume electric resistance can be obtained. If the porosity of the electrode portion 21 is lower than 30%, it may be deformed during manufacturing. When the porosity of the electrode part 21 is higher than 45%, the volume electric resistance may become too high. The porosity is a value measured with a mercury porosimeter.

  The electrode portion 21 preferably has an average pore diameter of 5 to 20 μm, and more preferably 7 to 15 μm. When the average pore diameter of the electrode portion 21 is in such a range, a suitable volume electric resistance can be obtained. When the average pore diameter of the electrode part 21 is smaller than 5 μm, the volume electric resistance may become too high. When the average pore diameter of the electrode part 21 is larger than 20 μm, the strength is weak and the electrode part 21 may be damaged. The average pore diameter is a value measured with a mercury porosimeter.

  It is preferable that the average particle diameter of the silicon carbide particle contained in the electrode part 21 is 10-60 micrometers, and it is still more preferable that it is 20-60 micrometers. When the average particle diameter of the silicon carbide particles contained in the electrode part 21 is in such a range, the volume electrical resistance of the electrode part 21 at 400 ° C. can be 0.1 to 2.0 Ωcm. When the average pore diameter of the silicon carbide particles contained in the electrode part 21 is smaller than 10 μm, the volume electric resistance at 400 ° C. of the electrode part 21 may become too large. If the average pore diameter of the silicon carbide particles contained in the electrode portion 21 is larger than 60 μm, the strength of the electrode portion 21 may be weak and may be damaged. The average particle diameter of the silicon carbide particles contained in the electrode part 21 is a value measured by a laser diffraction method.

  The ratio of the mass of silicon contained in the electrode portion 21 with respect to the “total mass of silicon carbide and silicon” contained in the electrode portion 21 is preferably 20 to 40 mass%, and is preferably 25 to 35 mass%. % Is more preferable. When the ratio of the mass of silicon to the total mass of silicon carbide and silicon contained in the electrode portion 21 is in such a range, an appropriate volume electric resistance can be obtained. When the ratio of the mass of silicon to the total mass of silicon carbide and silicon contained in the electrode part 21 is smaller than 20% by mass, the volume electric resistance may be excessively increased. And when larger than 40 mass%, it may become easy to deform | transform at the time of manufacture.

  In the honeycomb structure 100 of the present embodiment, the porosity of the electrode part 21 is 30 to 45%, the average pore diameter of the electrode part is 5 to 20 μm, and “silicon carbide and silicon contained in the electrode part 21” The ratio of the “mass of silicon” contained in the electrode part 21 with respect to the “total of the respective masses of” is 20 to 40% by mass, and the average particle diameter of the silicon carbide particles contained in the electrode part 21 is 10 to 10%. It is preferable that the volume electrical resistance of the electrode portion 21 is 0.1 to 2.0 Ωcm. Thereby, especially the honeycomb structure can generate heat uniformly during energization.

  In the honeycomb structure of the present embodiment, when a tangent line in contact with the outer periphery of the honeycomb structure portion is drawn at the central portion in the circumferential direction of the honeycomb structure portion in the cross section orthogonal to the cell extending direction, It is preferable that the tangent line is parallel to one of the partition walls. This makes it difficult to break during canning.

  Moreover, it is preferable that the thickness of the outer peripheral wall 3 which comprises the outermost periphery of the honeycomb structure 100 of this embodiment 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 supporting the catalyst may be small.

  In the honeycomb structure 100 of the present embodiment, the shape of the cell 2 in a cross section orthogonal to the extending direction of the cell 2 is preferably a quadrangle 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.

The shape of the honeycomb structure of the present embodiment is not particularly limited. For example, the bottom surface has a circular cylindrical shape (cylindrical shape), the bottom surface has an oval cylindrical shape, and the bottom surface has a polygonal shape (square, pentagon, hexagon, heptagon. , Octagons, etc.). The honeycomb structure preferably has a bottom area of 2000 to 20000 mm ² , and more preferably 4000 to 10000 mm ² . The length of the honeycomb structure in the central axis direction is preferably 50 to 200 mm, and more preferably 75 to 150 mm.

  The isostatic strength of the honeycomb structure 100 of the present embodiment is preferably 1 MPa or more. When the isostatic strength is less than 1 MPa, the honeycomb structure may be easily damaged when used as a catalyst carrier or the like. Isostatic strength is a value measured by applying hydrostatic pressure in water.

(2) Manufacturing method of honeycomb structure:
Next, the manufacturing method of one embodiment of the honeycomb structure of the present invention will be described.

  First, metal silicon (metal silicon powder), a binder, a surfactant, a pore former, water, and the like are added to silicon carbide powder (silicon carbide) to produce a forming raw material. It is preferable that the mass of the metal silicon is 10 to 30% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metal silicon. The average particle diameter of the silicon carbide particles in the silicon carbide powder is preferably 3 to 30 μm, and more preferably 5 to 20 μm. The average particle diameter of metal silicon (metal silicon powder) is preferably 2 to 20 μm. If it is smaller than 2 μm, the volume electric resistance may be too small. If it is larger than 20 μm, the volume electric resistance may become too large. The average particle diameter of silicon carbide particles and metal silicon (metal 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 metal silicon particles are metal silicon fine particles constituting the metal silicon powder. The total mass of the silicon carbide particles and the metal silicon is preferably 30 to 78 mass% with respect to the mass of the entire forming raw material.

  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 to 10% by mass with respect to the entire forming raw material.

  The water content is preferably 20 to 60% by mass with respect to the entire forming raw material.

  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 2% by mass or less with respect to the whole forming raw material.

  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 pore former content is preferably 10% by mass or less based on the entire forming raw material. The average particle diameter of the pore former is preferably 10 to 30 μm. If it is smaller than 10 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.

  Moreover, it is preferable that a shaping | molding raw material contains strontium carbonate as a sintering auxiliary agent. The content of the sintering aid is preferably 0.1 to 3% by mass with respect to the entire forming raw material.

  Next, the forming raw material is kneaded to form a clay. There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the kneaded material is extruded to form 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 porous partition walls that define and form a plurality of cells serving as fluid flow paths and an outer peripheral wall located at 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.

  It is preferable to dry the obtained honeycomb formed 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 is not a desired length, it is preferable that both end faces (both end portions) are cut to a desired length. The cutting method is not particularly limited, and examples thereof include a method using a circular saw cutting machine.

  Next, an electrode part forming raw material for forming the electrode part is prepared. When the main components of the electrode part are silicon carbide and silicon, the electrode part forming raw material is preferably formed by adding a predetermined additive to silicon carbide powder and silicon powder and kneading.

  Specifically, metal silicon (metal silicon powder), a binder, a surfactant, a pore former, water, and the like are added to silicon carbide powder (silicon carbide) and kneaded to prepare an electrode part forming raw material. It is preferable that the mass of the metal silicon is 20 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metal silicon. The average particle diameter of the silicon carbide particles in the silicon carbide powder is preferably 10 to 60 μm. The average particle diameter of metal silicon (metal silicon powder) is preferably 2 to 20 μm. If it is smaller than 2 μm, the volume electric resistance may be too small. If it is larger than 20 μm, the volume electric resistance may become too large. The average particle diameter of silicon carbide particles and metal silicon (metal 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 metal silicon particles are metal silicon fine particles constituting the metal silicon powder. The total mass of the silicon carbide particles and the metal silicon is preferably 40 to 80% by mass with respect to the mass of the entire electrode part forming raw material.

  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 0.1 to 2% by mass with respect to the entire electrode part forming raw material.

  The water content is preferably 19 to 55 mass% with respect to the entire electrode part forming raw material.

  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 2% by mass or less with respect to the entire electrode part forming raw material.

  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 pore former content is preferably 10% by mass or less based on the entire electrode part forming raw material. The average particle diameter of the pore former is preferably 10 to 30 μm. If it is smaller than 10 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.

  Moreover, it is preferable that an electrode part formation raw material contains strontium carbonate as a sintering aid. The content of the sintering aid is preferably 0.1 to 3% by mass with respect to the entire electrode part forming raw material.

  Next, a paste-like electrode part is formed by kneading a mixture obtained by mixing silicon carbide powder (silicon carbide), metal silicon (metal silicon powder), a binder, a surfactant, a pore former, water, and the like. It is preferable to use it as a raw material. The method of kneading is not particularly limited, and for example, a vertical stirrer can be used.

  Next, it is preferable to apply the obtained electrode part forming raw material to the side surface of the dried honeycomb formed body. The method for applying the electrode part forming raw material to the side surface of the honeycomb formed body is not particularly limited, and for example, a printing method can be used. The electrode part forming raw material is preferably applied to the side surface of the honeycomb formed body so as to have the shape of the electrode part in the honeycomb structure of the present invention. The thickness of an electrode part can be made into desired thickness by adjusting the thickness when apply | coating an electrode part formation raw material. Thus, since the electrode part can be formed simply by applying the electrode part forming raw material to the side surface of the honeycomb formed body, drying and firing, the electrode part can be formed very easily.

  Next, it is preferable to dry the electrode part forming raw material applied to the side surface of the honeycomb formed body. The drying conditions are preferably 50 to 100 ° C.

  Next, it is preferable to produce a member for forming an electrode terminal protrusion. The electrode terminal protrusion forming member is attached to the honeycomb formed body to become an electrode terminal protrusion. The shape of the electrode terminal protrusion forming member can be formed in various shapes described in the embodiment of the honeycomb structure. And it is preferable to affix the obtained electrode terminal protrusion part forming member to the part by which the electrode part formation raw material was apply | coated of the honeycomb molded object to which the electrode part formation raw material was apply | coated. In addition, the order of preparation of the honeycomb formed body, preparation of the electrode part forming raw material, and preparation of the electrode terminal protrusion part forming member may be any order.

  The electrode terminal protrusion forming member is preferably obtained by molding and drying an electrode terminal protrusion forming raw material (raw material for forming the electrode terminal protrusion forming member). The electrode terminal protrusion forming raw material is preferably formed by adding predetermined additives to silicon carbide powder and silicon powder and kneading them.

  Specifically, metal silicon (metal silicon powder), a binder, a surfactant, a pore former, water, etc. are added to silicon carbide powder (silicon carbide) and kneaded to produce an electrode terminal protrusion forming raw material. To do. It is preferable that the mass of the metal silicon is 20 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metal silicon. The average particle diameter of the silicon carbide particles in the silicon carbide powder is preferably 10 to 60 μm. The average particle diameter of metal silicon (metal silicon powder) is preferably 2 to 20 μm. If it is smaller than 2 μm, the volume electric resistance may be too small. If it is larger than 20 μm, the volume electric resistance may become too large. The average particle diameter of silicon carbide particles and metal silicon (metal 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 metal silicon particles are metal silicon fine particles constituting the metal silicon powder. The total mass of the silicon carbide particles and the metal silicon is preferably 50 to 85 mass% with respect to the mass of the entire electrode terminal protrusion forming raw material.

  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 binder content is preferably 1 to 10% by mass with respect to the entire electrode terminal protrusion forming raw material.

  It is preferable that water content is 15-30 mass% with respect to the whole electrode terminal protrusion part forming raw material.

  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 2% by mass or less based on the entire electrode terminal protrusion forming raw material.

  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 pore former content is preferably 10% by mass or less based on the entire electrode terminal protrusion forming raw material. The average particle diameter of the pore former is preferably 10 to 30 μm. If it is smaller than 10 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.

  Next, a mixture obtained by mixing silicon carbide powder (silicon carbide), metal silicon (metal silicon powder), a binder, a surfactant, a pore former, water, and the like is kneaded to obtain a material for forming electrode terminal protrusions. It is preferable that The method of kneading is not particularly limited, and for example, a kneader can be used.

  The method of forming the obtained electrode terminal protrusion forming raw material into the shape of the electrode terminal protrusion forming member is not particularly limited, and examples thereof include a method of processing after extrusion.

  It is preferable that the electrode terminal protrusion forming raw material is formed into the shape of the electrode terminal protrusion forming member and then dried to obtain the electrode terminal protrusion forming member. The drying conditions are preferably 50 to 100 ° C.

  Next, the electrode terminal protrusion forming member is preferably attached to the honeycomb formed body to which the electrode portion forming raw material is applied. The method for attaching the electrode terminal protrusion forming member to the honeycomb formed body (the portion where the electrode part forming raw material of the honeycomb formed body is applied) is not particularly limited, but the electrode terminal protrusion is formed using the electrode part forming raw material. It is preferable to attach the member for use to the honeycomb formed body. For example, an electrode part forming raw material is applied to the “surface that adheres to the honeycomb formed body (surface that contacts the honeycomb formed body)” of the electrode terminal protrusion forming member, and the “surface on which the electrode part forming raw material is applied” is the honeycomb surface. The electrode terminal protrusion forming member is preferably attached to the honeycomb molded body so as to be in contact with the molded body.

  Then, the honeycomb molded body to which the electrode part forming raw material is applied and the electrode terminal protrusion part forming member is attached is dried and fired, and the honeycomb structure part and a pair disposed on the side surface of the honeycomb structure part are disposed. And electrode terminal protrusions disposed on the respective surfaces of the pair of electrode portions.

  The drying conditions at this time are preferably 50 to 100 ° C.

  Moreover, in order to remove a binder etc. before baking, it is preferable to perform temporary baking. Pre-baking is preferably performed at 400 to 500 ° C. for 0.5 to 20 hours in an air atmosphere. The method of temporary baking and baking is not particularly limited, and baking can be performed using an electric furnace, a gas furnace, or the like. The firing conditions are preferably 1400 to 1500 ° C. for 1 to 20 hours in an inert atmosphere such as nitrogen or argon. Moreover, after baking, in order to improve durability, it is preferable to perform oxygenation treatment at 1200 to 1350 ° C. for 1 to 10 hours.

  The electrode terminal protrusion forming member may be attached before firing the honeycomb formed body, or may be attached after firing. When the electrode terminal protrusion forming member is attached after the honeycomb formed body is fired, it is preferably fired again under the above conditions.

  Next, a metal terminal portion made of a metal material is cut out or manufactured by a plate material pressing method. The metal terminal portion may be manufactured before the honeycomb structure portion is manufactured.

  In addition, it is preferable to form the shape of a metal terminal part in the concave shape or convex shape from which the shape in a junction part with an electrode terminal protrusion part becomes a complementary shape. As a metal material for forming the metal terminal portion, Kovar, stainless steel, Inconel or the like can be suitably used.

  Next, the obtained metal terminal part and the electrode terminal protrusion part arrange | positioned at the surface of a pair of electrode part arrange | positioned at the side surface of a honeycomb structure part are joined through a brazing material. Specifically, a paste-like brazing material is applied to the end of the electrode terminal protrusion, a metal terminal is fitted therein, and heated at a predetermined temperature in a vacuum furnace. A metal terminal part is joined in the state electrically connected through the brazing material. Thus, a honeycomb structure as shown in FIGS. 1 to 5 can be manufactured.

  As the type of brazing material, the brazing material described so far in the embodiments of the honeycomb structure can be suitably used. Further, the temperature at the time of bonding, the bonding atmosphere (for example, bonding in vacuum), and the like can be appropriately selected according to the type of brazing material to be used.

  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
Silicon carbide (SiC) powder and metal silicon (Si) powder are mixed at a mass ratio of 80:20, and strontium carbonate as a sintering aid, hydroxypropyl methylcellulose as a binder, and a water absorbent resin as a pore former. In addition to the addition, water was added to form a forming raw material, and the forming raw material was kneaded with a vacuum kneader to prepare a cylindrical clay. The binder content is 7 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass, and the content of strontium carbonate is silicon carbide (SiC) powder and metal silicon ( Si) powder is 1 part by mass, and the pore former content is 3 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass, The content of was 42 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder was 100 parts by mass. The average particle diameter of the silicon carbide powder was 20 μm, and the average particle diameter of the metal silicon powder was 6 μm. Moreover, the average particle diameter of the pore former was 20 μm. The average particle diameters of silicon carbide, metal silicon and pore former are values measured by a laser diffraction method.

  The obtained columnar kneaded material was formed using an extrusion molding machine to obtain a honeycomb formed body. The obtained honeycomb formed body was dried by high-frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both end surfaces were cut by a predetermined amount.

  Next, silicon carbide (SiC) powder and metal silicon (Si) powder are mixed at a mass ratio of 60:40, and strontium carbonate as a sintering aid, hydroxypropylmethylcellulose as a binder, glycerin as a humectant, A surfactant was added as a dispersant, and water was added and mixed. The mixture was kneaded to obtain an electrode part forming raw material. The content of strontium carbonate is 1 part by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass, and the binder content is silicon carbide (SiC) powder and metal silicon ( When the total of Si) powder is 100 parts by mass, the content of glycerin is 10 when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass. The content of the surfactant is 0.3 parts by mass when the total of the silicon carbide (SiC) powder and the metal silicon (Si) powder is 100 parts by mass, and the water content is silicon carbide. When the total of (SiC) powder and metal silicon (Si) powder was 100 parts by mass, it was 42 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.

  Next, the electrode part forming raw material was applied to the side surface of the dried honeycomb molded body in a strip shape having a thickness of 0.5 mm and a width of 60 mm so as to extend between both end faces of the honeycomb molded body. The electrode part forming raw material was applied to two sides of the dried honeycomb formed body. And, in the cross section orthogonal to the cell extending direction, one of the portions where the electrode part forming raw material is applied is arranged on the opposite side of the center of the honeycomb formed body with respect to the other. I made it.

  Next, the electrode part forming raw material applied to the honeycomb formed body was dried. The drying conditions were 70 ° C.

  Next, silicon carbide (SiC) powder and metal silicon (Si) powder were mixed at a mass ratio of 60:40, to which hydroxypropylmethylcellulose was added as a binder, and water was added and mixed. The mixture was kneaded to obtain an electrode terminal protrusion forming raw material. The electrode terminal protrusion forming raw material was made into clay using a vacuum kneader. The binder content is 4 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass, and the water content is silicon carbide (SiC) powder and metal silicon (Si ) When the total powder was 100 parts by mass, it was 22 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 obtained clay is formed using a vacuum kneader, processed into a shape like the electrode terminal protrusion 22 shown in FIGS. 1 to 5, and dried to form an electrode terminal protrusion forming member. Obtained. The drying conditions were 70 ° C. The portion corresponding to the plate-like substrate 22a was 3 mm × 12 mm × 15 mm in size. Further, the portion corresponding to the protruding portion 22b was formed in a cylindrical shape having a bottom surface diameter of 10 mm and a length in the central axis direction of 10 mm. Two electrode terminal protrusion forming members were produced.

  Next, each of the two electrode terminal protrusion forming members was attached to each of the portions of the honeycomb formed body to which the electrode portion forming raw material was applied. The electrode terminal protrusion forming member was attached to the portion of the honeycomb formed body to which the electrode part forming raw material was applied using the electrode part forming raw material. Thereafter, the honeycomb formed body to which the electrode part forming raw material is applied and the electrode terminal protrusion forming member is attached is degreased, fired, and further oxidized to form a honeycomb structure (however, the metal terminal part is not connected). Got. The degreasing conditions were 550 ° C. for 3 hours. The firing conditions were 1450 ° C. and 2 hours in an argon atmosphere. The conditions for the oxidation treatment were 1300 ° C. and 1 hour. The obtained honeycomb structure includes a honeycomb structure portion A1 shown in Table 1, an electrode portion B1 shown in Table 2, and an electrode terminal protrusion C1 shown in Table 3. Table 1 shows the configuration of the honeycomb structure, Table 2 shows the configuration of the electrode portion, and Table 3 shows the configuration of the electrode terminal protrusion.

The average pore diameter (pore diameter) of the partition walls of the obtained honeycomb structure was 8.6 μm, and the porosity was 45%. The average pore diameter and porosity are values measured with a mercury porosimeter. The honeycomb structure had a partition wall thickness of 90 μm and a cell density of 90 cells / cm ² . The bottom surface of the honeycomb structure was a circle having a diameter of 93 mm, and the length of the honeycomb structure in the cell extending direction was 100 mm. Moreover, the isostatic strength of the obtained honeycomb structure was 2.5 MPa. Isostatic strength is the breaking strength measured by applying hydrostatic pressure in water.

  Further, the metal terminal portion for electrical connection with the electrode terminal protrusion portion of the honeycomb structure is processed into a concave shape like the metal terminal portion 23 shown in FIGS. 1 and 2 using Kovar. Formed. In addition, the inner diameter (diameter) of the hollow portion of the concave metal terminal portion was a columnar shape of 10.1 mm so that a brazing filler metal layer of 0.05 mm was disposed between the concave portions of the metal terminal portions. The thickness of the concave wall portion was set to 0.5 mm.

  Next, the obtained metal terminal portion and the electrode terminal protrusion portion of the honeycomb structure are joined using a brazing material containing 90% by mass of nickel and chromium with respect to the entire brazing material, thereby forming the honeycomb structure. Produced.

  With respect to the joint portion between the electrode terminal protrusion and the metal terminal portion of the obtained honeycomb structure, the “joint strength (initial)”, “joint resistance value (initial)”, “joint portion” are as follows. Strength (after the thermal cycle) "and" resistance value of the joint (after the thermal cycle) ". The results are shown in Table 4.

  In addition, as shown in FIG. 12A and FIG. 12B, the various measurements described above are 20 mm long test pieces (test pieces 122 of electrode terminal protrusions) corresponding to twice the length of the protrusions of the electrode terminal protrusions. The metal terminal portions 23 were joined to the both end portions of the test piece 122 of the electrode terminal protrusions with a brazing material. Here, FIG. 12A is a plan view showing a method for measuring the strength of the electrode terminal protrusion, the metal terminal, and the joint, and FIG. 12B is a measurement of the resistance value of the electrode terminal protrusion, the metal terminal, and the joint. It is a top view which shows a method.

(Joint strength (initial))
As shown in FIG. 12A, the metal terminal portions 23 are respectively joined to both ends of the test piece 122 of the electrode terminal protrusion by a brazing material, and the metal terminal portions 23 are pulled and joined to both by the method of the arrow in FIG. 12A. The strength (N) when the part peeled was measured. The strength at the time of peeling was defined as “joint strength (initial)”. In addition, the case where the intensity | strength of a junction part is 19.6N or more is set as a pass (good).

(Joint strength (after cooling cycle))
After the test piece 122 and the metal terminal portion 23 shown in FIG. 12A are heated to 700 ° C. using an electric furnace, a cooling cycle for cooling to 100 ° C. is repeated 100 times, and the strength (initial) of the above-described joint portion is measured. By the same method, the strength (N) when the joint part peeled was measured. The strength at the time of peeling was defined as “joint strength (after cooling cycle)”. In addition, the case where the intensity | strength of a junction part is 19.6N or more is set as a pass (good).

(Junction resistance (initial))
As shown in FIG. 12B, the metal terminal portions 23 are respectively joined to both ends of the test piece 122 of the electrode terminal protrusion by a brazing material, and the other metal terminal portion is connected from the one metal terminal portion 23 via the test piece 122. Resistance values (mΩ) up to 23 were measured. This resistance value was defined as “resistance value of joint (initial)”.

(Resistance value of the joint (after cooling cycle))
After the test piece 122 and the metal terminal portion 23 shown in FIG. 12A are heated to 700 ° C. using an electric furnace, a cooling cycle for cooling to 100 ° C. is repeated 100 times, and the resistance value (initial) of the above-described joint portion is determined. By the same method as the measurement, the resistance value (mΩ) from one metal terminal portion 23 to the other metal terminal portion 23 via the test piece 122 was measured. This resistance value was defined as “the resistance value of the joint (after the thermal cycle)”.

In Table 1, “SiC blending amount (mass%)” indicates the blending ratio (mass ratio) of silicon carbide with respect to the total mass of silicon carbide and metal silicon, and “Si blending quantity (mass%)” is The compounding ratio (mass ratio) of metal silicon with respect to the total mass of silicon carbide and metal silicon is shown. Further, “pore forming material blending amount (pore forming material) (mass part)” indicates a mass part of the pore forming material when the entire forming raw material is 100 parts by mass, and “water ratio (water) (mass part”). ")" Indicates a part by weight of water when the entire forming raw material is 100 parts by weight. “Cell shape” indicates the shape of a cell in a cross section perpendicular to the cell extending direction. “Rib thickness (μm)” indicates the thickness of the partition wall. “Number of cells (cells / cm ² )” represents the cell density in a cross section perpendicular to the cell extending direction of the honeycomb structure. Moreover, the porosity and pore diameter in Table 1 indicate the porosity and average pore diameter of the partition walls of the honeycomb structure part. The porosity and pore diameter in Table 2 indicate the porosity and average pore diameter of the electrode part. The porosity and pore diameter in Table 3 indicate the porosity and average pore diameter of the electrode terminal protrusion.

(Examples 2 to 5)
Except for changing the type of the brazing material as shown in Table 4, a honeycomb structure was produced by the same method as in Example 1, and “Joint strength (initial)” was obtained by the same method as in Example 1. “,“ Resistance value of the bonded portion (initial) ”,“ strength of the bonded portion (after cooling cycle) ”, and“ resistance value of the bonded portion (after cooling cycle) ”were measured. Table 4 shows the measurement results.

(Example 6)
As shown in FIG. 10, the honeycomb structure was formed by the same method as in Example 1 except that the metal coating 27 was produced by spraying silicon (Si) on a part of the surface of the electrode terminal protrusion 22. The “joint strength (initial)”, “joint resistance (initial)”, “joint strength (after cooling cycle)”, and “joint strength” were prepared by the same method as in Example 1. "Resistance value (after cooling cycle)" was measured. Table 4 shows the measurement results.

(Example 7)
As shown in FIG. 9, a range corresponding to 80% of the connection area between the electrode terminal protrusion 22 and the metal terminal portion 23 is joined through a crystallized glass 26 containing SiO ₂ and Al ₂ O _3. A honeycomb structure was produced by the same method as in Example 1, and “joint strength (initial)”, “resistance value of joint (initial)”, “joint” by the same method as in Example 1. ”Strength (after cooling cycle)” and “resistance value of the joint (after cooling cycle)” were measured. Table 4 shows the measurement results.

(Comparative Example 1)
A honeycomb structure part, an electrode part, and an electrode terminal protrusion are produced by the same method as in Example 1, and the outer periphery of the electrode terminal protrusion is covered with a 1 mm stainless steel sheet metal, and both ends of the sheet metal are covered. By overlapping the parts and fixing them by screwing, the electrode terminal protrusions and the thin metal plate corresponding to the metal terminal parts were electrically connected, and a honeycomb structure of Comparative Example 1 was produced. With respect to the obtained honeycomb structure, “joint strength (initial)”, “joint resistance (initial)”, “joint strength (after cooling cycle)” was performed in the same manner as in Example 1. And “the resistance value of the joint (after the thermal cycle)” were measured. Table 4 shows the measurement results.

  As shown in Table 1, the honeycomb structures of Examples 1 to 7 had high joint strength at the initial stage and after the thermal cycle. Further, the resistance value at the initial stage and after the thermal cycle was also a sufficiently low resistance value for electrical connection. On the other hand, the honeycomb structure of Comparative Example 1 had extremely low strength at the bonded portion at the initial stage and after the thermal cycle.

  The honeycomb structure of the present invention can be suitably used as a carrier for a catalyst device that purifies exhaust gas discharged from an internal combustion engine in various fields such as chemistry, electric power, and steel.

1: partition wall, 2: cell, 3: outer peripheral wall, 4: honeycomb structure portion, 5: side surface, 11: one end surface, 12: the other end surface, 21: electrode portion, 22: electrode terminal protrusion, 22a: substrate 22b: protrusion, 23: metal terminal, 24: brazing material, 25: gap, 26: crystallized glass, 27: metal coating, 100: honeycomb structure, O: center, R: circumferential direction.

Claims (10)

A porous partition wall defining a plurality of cells extending from one end surface to the other end surface, which serves as a fluid flow path, and an outer peripheral wall located at the outermost periphery; silicon carbide particles as an aggregate; and A cylindrical honeycomb structure portion made of a ceramic material containing silicon as a binder for bonding silicon carbide particles;
A pair of electrode portions disposed on a side surface of the honeycomb structure portion;
Electrode terminal protrusions disposed on the respective surfaces of the pair of electrode portions;
A metal terminal portion made of a metal material electrically connected to the electrode terminal protrusion, and
The pair of electrode parts and the electrode terminal protrusions are made of a conductive ceramic material mainly composed of silicon carbide and silicon,
A honeycomb structure formed by joining the electrode terminal protrusion and the metal terminal in an electrically connected state through a brazing material.   The electrode terminal protrusion is formed in a convex shape or a concave shape, and the metal terminal portion is formed in a concave shape or a convex shape in which the shape at the joint portion with the electrode terminal protrusion is a complementary shape. The honeycomb structure according to claim 1.   The electrode terminal protrusion and the metal terminal portion have a gap between a convex tip of the concave and convex shape that is a complementary shape and a concave recess, and the electrode terminal protrusion and the metal terminal portion The honeycomb structure according to claim 2, wherein the concavo-convex-shaped side surface portion is joined in a state of being electrically connected via the brazing material. The electrode terminal protrusion is formed in a convex shape, and the metal terminal portion is formed in a concave shape,
The honeycomb structure according to claim 2 or 3, wherein the metal terminal portion has a wall portion forming a concave shape with a thickness of 0.1 to 5 mm. The electrode terminal protrusion is formed in a convex shape, and the metal terminal portion is formed in a concave shape,
The honeycomb structure according to any one of claims 2 to 4, wherein the metal terminal portion has a tapered shape in which an end surface shape of a wall portion forming a concave shape protrudes from an inner peripheral side of the concave shape.   The honeycomb according to any one of claims 1 to 5, wherein the brazing material contains at least one metal selected from the group consisting of nickel, chromium, titanium, manganese, iron, copper, and silver. Structure.   The honeycomb structure according to any one of claims 1 to 6, wherein the metal terminal portion is made of Kovar, stainless steel, or Inconel.   A metal coating is disposed on at least a part of the surface of the electrode terminal projection, and the metal coating on the surface of the electrode terminal projection and the metal terminal are electrically connected via the brazing material. The honeycomb structure according to any one of claims 1 to 7, wherein the honeycomb structure is joined in a state of being formed.   The honeycomb structure according to any one of claims 1 to 8, wherein a part of a connection portion between the electrode terminal protrusion and the metal terminal is joined through crystallized glass. Each of the pair of electrode portions is formed in a band shape extending between both ends and extending in the cell extending direction of the honeycomb structure portion,
In the cross section perpendicular to the cell extending direction, one of the pair of electrode portions is opposite to the other electrode portion of the pair of electrode portions across the central portion of the honeycomb structure portion. The honeycomb structure according to any one of claims 1 to 9, which is disposed on a side.

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