WO2014051176A1 - Insulator composition for oxygen sensor, and oxygen sensor using same - Google Patents

Insulator composition for oxygen sensor, and oxygen sensor using same Download PDF

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WO2014051176A1
WO2014051176A1 PCT/KR2012/007830 KR2012007830W WO2014051176A1 WO 2014051176 A1 WO2014051176 A1 WO 2014051176A1 KR 2012007830 W KR2012007830 W KR 2012007830W WO 2014051176 A1 WO2014051176 A1 WO 2014051176A1
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composition
aluminosilicate glass
oxygen sensor
insulator composition
magnesia
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PCT/KR2012/007830
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French (fr)
Korean (ko)
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김경원
윤상옥
정광현
김관수
강현규
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경원산업 주식회사
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Priority to KR1020157007693A priority Critical patent/KR20150073164A/en
Priority to PCT/KR2012/007830 priority patent/WO2014051176A1/en
Publication of WO2014051176A1 publication Critical patent/WO2014051176A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/12—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances ceramics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C14/00—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
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    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
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    • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/03—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • C04B35/04—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on magnesium oxide
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    • C04B35/64—Burning or sintering processes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4071—Cells and probes with solid electrolytes for investigating or analysing gases using sensor elements of laminated structure
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2214/00—Nature of the non-vitreous component
    • C03C2214/20—Glass-ceramics matrix
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    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
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    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3427—Silicates other than clay, e.g. water glass
    • C04B2235/3436—Alkaline earth metal silicates, e.g. barium silicate
    • C04B2235/3445—Magnesium silicates, e.g. forsterite
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    • C04B2237/345—Refractory metal oxides
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Definitions

  • the present invention relates to an insulator composition for an oxygen sensor, and more particularly to an insulator composition for an oxygen sensor that is excellent in airtightness and electrical insulation as an insulating layer and has excellent adhesion to a solid electrolyte layer.
  • the present invention also relates to an oxygen sensor using the insulator composition.
  • the engine of an automobile changes the output, fuel consumption and exhaust gas amount of the engine according to the air-fuel ratio, which is a mixture ratio of air and fuel, it is necessary to control the engine to maintain an optimum air-fuel ratio at all times. In particular, such efficient control results in energy savings and reduction of harmful emissions.
  • This air-fuel ratio is obtained by measuring the content of oxygen contained in the exhaust gas emitted from the engine of the vehicle, the oxygen sensor is usually used for such a measurement.
  • the oxygen sensor transmits the internal both ends of the voltage generated according to the oxygen content of the exhaust gas to the ECU (Electronic Control Unit), which is an engine control device, and the ECU flows into the engine based on the voltage data received from the oxygen sensor.
  • the air-fuel ratio is controlled by adjusting the fuel supply amount.
  • the flat plate type oxygen sensor can have a smaller size than the tube type and can shorten the time to start the sensor.
  • Such a plate-type oxygen sensor is well disclosed in DE2907032 A1 (published on August 28, 1980) and WO 1998/30984 (published on July 16, 1998).
  • FIG. 1 schematically shows a structure of a general flat plate type oxygen sensor.
  • the general flat plate type oxygen sensor 100 includes a sensor unit 120 on a substrate 170 such as alumina, and a heater unit 140 connected to the electrical insulating layer 140. .
  • the sensor unit 120 includes a measurement electrode 122 and a reference electrode 124 disposed to face each other with the solid electrolyte layer 123 interposed therebetween.
  • a solid electrolyte layer 125 having a reference channel 127 through which (reference) air flows is positioned below the reference electrode 124, and an upper end of the measurement electrode 122 is a protective layer that is a porous oxide film ( 121).
  • the solid electrolyte layers 123 and 125 have oxygen ion conductivity and generally have a stabilized zirconia (YSZ) composition.
  • the measuring electrode 122 faces the exhaust gas and the reference electrode 124 faces the (reference) atmosphere, an electric potential difference is generated between the two electrodes, thereby detecting such a voltage, and thus the oxygen content in the exhaust gas. Is detected.
  • the heater unit 13 includes a heating element, that is, a resistance heating element 142, the operation of the sensor unit 120 by heating to the operating temperature of the oxygen sensor (for example, 450 ⁇ 900 °C) Make it happen quickly.
  • a heating element that is, a resistance heating element 142
  • the insulating layer 140 is generally made of alumina (Al 2 O 3 ) composition.
  • alumina (Al 2 O 3 ) composition has a different sintering behavior than that of the stabilized zirconia (YSZ) composition of the solid electrolyte layer 125, so that the alumina (Al 2 O 3 ) composition is inevitably formed as a porous body to compensate for the thermal expansion coefficient. Due to the porosity, since the exhaust gas easily diffuses into the reference atmosphere in the reference channel 127 and contaminates it, the measurement value of the sensor unit 120 becomes unstable and causes a fatal problem that causes damage to the heater unit.
  • WO 1998/30984 discloses a composition composed of a crystalline nonmetallic material such as alumina and a glass forming material of alkaline earth silicate glass. Such a composition can control the plastic deformation according to the compressive stress and form an insulating layer having excellent airtightness by using the softening property of the glass, thereby compensating for the different sintering behavior and coefficient of thermal expansion between alumina and stabilized zirconia.
  • a fine powder having a particle size of d 50 ⁇ 0.4 ⁇ m of crystalline nonmetallic materials such as alumina should be used, and a large amount of glass forming material made of alkaline earth silicate glass is used at 50 wt%. Accordingly, there is a problem that the lifetime of the oxygen sensor is limited as the thermal conductivity of the insulating layer decreases.
  • an object of the present invention is to provide an insulator composition for an oxygen sensor having excellent airtightness and electrical insulation and excellent adhesion with a solid electrolyte layer.
  • Insulator composition for an oxygen sensor according to an aspect of the present invention for achieving the above object may include one or more of magnesia, sodium aluminosilicate glass and calcium aluminosilicate glass as a sintering aid.
  • the content of the sintering aid may be 10 ⁇ 40wt%, preferably 10 ⁇ 30wt% relative to the total amount of the insulator composition.
  • composition of the sodium aluminosilicate glass may include components in the following contents:
  • composition of the calcium aluminosilicate glass may include components of the following contents:
  • the firing temperature of the insulator composition may be in the range of 1300 ⁇ 1500 °C.
  • the oxygen sensor according to another aspect of the present invention comprises a solid electrolyte layer, a measurement electrode attached to each surface of the solid electrolyte layer, respectively, the measurement electrode facing the exhaust gas and the reference electrode facing the atmosphere and A sensor unit for detecting oxygen concentration by detecting a potential difference between the reference electrodes;
  • An insulating layer which is integrally bonded to the lower surface of the sensor part and is made of an insulator composition comprising at least one of sodium aluminosilicate glass and calcium aluminosilicate glass as magnesia and a sintering aid and bonded to the solid electrolyte layer;
  • Including a heating element embedded therein may include a heater unit for heating the sensor unit.
  • FIG. 1 is a schematic structural diagram of a general flat plate type oxygen sensor.
  • Figure 2 is a flow chart of the manufacturing process by the oxide mixing method according to an embodiment of the present invention.
  • Figure 3 is a graph of the change in relative density according to the addition ratio and sintering temperature when low alkali aluminosilicate glass powder is added to magnesia as embodiments of the present invention.
  • Figure 4 is a graph of the change in relative density according to the addition ratio and sintering temperature when the alkali-free aluminosilicate glass powder is added to magnesia as another embodiment of the present invention.
  • FIG. 5 is a crystal phase analysis of a laminate co-fired at 1350 ° C. by stacking an insulating layer made of a composition in which calcium aluminosyl case glass powder is added to magnesia and a solid electrolyte layer of a stabilized zirconia (YSZ) composition according to the present invention.
  • XRD X-ray diffraction analysis
  • FIG. 6 is a scanning electron microscope (FE-SEM) photograph of the laminate of FIG.
  • the present invention relates to an insulator composition that can be effectively used as an insulating layer (eg, "140" in FIG. 1) in the aforementioned flat plate oxygen sensor (eg, "100" in FIG. 1).
  • an insulator composition that can be effectively used as an insulating layer (eg, "140" in FIG. 1) in the aforementioned flat plate oxygen sensor (eg, "100” in FIG. 1).
  • excellent airtightness and insulation resistance are required for the insulator composition, and as a requirement for having such characteristics, the insulator composition should have a relative density of 95% or more and a specific resistance of 1 M ⁇ ⁇ cm or more.
  • magnesia (MgO) composition can replace the conventional alumina composition as the insulator composition for the oxygen sensor.
  • the thermal conductivity of alumina is 28 ⁇ 32W / (m * K), while magnesia is 45 ⁇ 60W / (m * K), which is twice as good as alumina. That is, the magnesia composition has a similar thermal expansion coefficient and high thermal conductivity to Yttria Stabilized Zirconia (YSZ) ceramic of the solid electrolyte layer (eg, “125” in FIG. 1).
  • YSZ Yttria Stabilized Zirconia
  • the inventors of the present invention when the alkali aluminosilicate and / or alkali-free aluminosilicate glass powder is added to the magnesia (MgO) as a sintering aid, it is possible to co-fire with the solid electrolyte layer, thermal conductivity, insulation and It was found that the sintering characteristics were excellent.
  • MgO magnesia
  • composition formula of the insulator composition for an oxygen sensor according to the present invention is as follows:
  • x is a wt% unit and the glass powder is a low alkali aluminosilicate glass powder or an alkali free aluminosilicate glass powder.
  • the particle size of these powders is preferably in the range of 1 to 2 ⁇ m.
  • the low alkali aluminosilicate glass powder composition may be sodium aluminosilicate, and includes the following components. Wherein each wt% is relative to the total low alkali aluminosilicate glass powder composition:
  • the components of the low alkali aluminosilicate glass powder composition preferably have the following composition ratio. Wherein each wt% is relative to the total low alkali aluminosilicate glass powder composition:
  • alkali-free aluminosilicate glass composition may be calcium aluminosilicate, and includes the following. Wherein each wt% is relative to the total alkali free aluminosilicate glass powder composition:
  • the components of the alkali-free aluminosilicate glass powder composition preferably have the following composition ratio. Wherein each wt% is relative to the total alkali free aluminosilicate glass powder composition:
  • the insulator composition for an oxygen sensor according to the present invention may be prepared by various manufacturing methods known in the art, including an oxide mixing method and a thick film printing method such as a doctor blade.
  • Fig. 2 illustrates a manufacturing process by the oxide mixing method, but the manufacturing method of the present invention is not limited thereto.
  • the low alkali aluminosilicate or alkali free aluminosilicate glass is milled as a sintering aid to grind to a particle size of about 1 to 2 ⁇ m (S202).
  • the sintering aid prepared as described above is added to magnesia (MgO), and the alcohol is milled with a solvent to be mixed and ground (S204). Thereafter, the ground mixture is dried (S206).
  • the dried mixed powder is molded at a predetermined pressure (for example, molded by applying a pressure of 100 MPa to a mold having a diameter of 15 mm), and sintered at a temperature of 1300 to 1500 ° C. for 2 hours (S208).
  • a predetermined pressure for example, molded by applying a pressure of 100 MPa to a mold having a diameter of 15 mm
  • the sintered body thus prepared was evaluated for sintering characteristics through relative density measurements, and then, electrodes and lead wires made of materials known in the art including silver (Ag), platinum (Pt), and palladium (Pd) were formed on both surfaces thereof. Attached and heat treated at 800 °C for 1 hour to prepare an insulator for oxygen sensor (S210).
  • Example 1 10 wt% of a low alkali aluminosilicate glass powder was added to 90 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The mixed powder thus dried was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered at a temperature of 1350 ° C. for 2 hours using an electric furnace.
  • the manufactured sintered body was evaluated for its sintering characteristics by measuring its relative density, and the silver (Ag) electrode and silver (Ag) lead wire were attached to both surfaces, and heat-treated at 800 ° C for 1 hour, and then the insulation characteristics were measured at 700 ° C through specific resistance measurement. Evaluated.
  • the relative density was 97.4%
  • the porosity was 2.6%
  • the specific resistance was 1.1Mcm.
  • Example 2 the mixed powder composition and the manufacturing process are the same as those in Example 1, except that the sintering temperature is different. That is, 10 wt% of a low alkali aluminosilicate glass powder was added to 90 wt% of magnesia in the same composition and process as in Example 1, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 98.1%
  • the porosity was 1.9%
  • the specific resistance was 1.4Mcm.
  • Example 3 20 wt% of a low alkali aluminosilicate glass powder was added to 80 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.7%
  • the porosity was 0.3%
  • the specific resistance was 1.8Mcm.
  • Example 4 the mixed powder composition and the manufacturing process are the same as those in Example 3, except that the sintering temperature is different. That is, in the same composition and process as in Example 3, 20 wt% of a low alkali aluminosilicate glass powder was added to 80 wt% of magnesia, mixed, pulverized and dried, and then the dried mixed powder was molded. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the resistivity was 2.0 Mcm.
  • Example 5 a low alkali aluminosilicate glass powder was added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the specific resistance was 1.5Mcm.
  • Example 6 the mixed powder composition and manufacturing process were the same as those in Example 5, except that the sintering temperature was different. That is, 30 wt% of a low alkali aluminosilicate glass powder was added to 70 wt% of magnesia in the same composition and process as in Example 5, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 99.5%
  • the porosity was 0.5%
  • the specific resistance was 1.1Mcm.
  • Example 7 40 wt% of low alkali aluminosilicate glass powder was added to 60 wt% of magnesia, and the alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the specific resistance was 1.2Mcm.
  • Example 8 the mixed powder composition and the manufacturing process were the same as those in Example 7, except that the sintering temperature was different. That is, in the same composition and process as in Example 7, 40 wt% of a low alkali aluminosilicate glass powder was added to 60 wt% of magnesia, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 99.3%
  • the porosity was 0.7%
  • the specific resistance was 0.9Mcm.
  • Example 9 10 wt% of alkali-free aluminosilicate glass powder was added to 90 wt% of magnesia, and alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 92.5%
  • the porosity was 7.5%
  • the specific resistance was 0.7Mcm.
  • Example 10 the mixed powder composition and the manufacturing process were the same as those in Example 9, except that the sintering temperature was different. That is, in the same composition and process as in Example 9, 10 wt% of alkali-free aluminosilicate glass powder was added to 90 wt% of magnesia, mixed, pulverized and dried, and then the dried mixed powder was molded. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 96.5%
  • the porosity was 3.5%
  • the specific resistance was 0.9Mcm.
  • Example 11 20 wt% of alkali-free aluminosilicate glass powder was added to 80 wt% of magnesia, and alcohol was mixed and pulverized in a ball mill to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 95.7%
  • the porosity was 4.3%
  • the specific resistance was 1.0Mcm.
  • Example 12 the mixed powder composition and the manufacturing process were the same as those in Example 11, except that the sintering temperature was different. That is, 20 wt% of alkali-free aluminosilicate glass powder was added to 80 wt% of magnesia in the same composition and process as in Example 11, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 98.6%
  • the porosity was 1.4%
  • the specific resistance was 1.3Mcm.
  • Example 13 an alkali free aluminosilicate glass powder was added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the prepared sintered body was evaluated for the sintering characteristics and the insulating characteristics in the same process as in Example 1.
  • the relative density was 99.5%
  • the porosity was 0.5%
  • the specific resistance was 2.1 Mcm.
  • Example 14 the mixed powder composition and the manufacturing process were the same as those in Example 13, except that the sintering temperature was different. That is, 30 wt% of alkali-free aluminosilicate glass powder was added to 70 wt% of magnesia in the same composition and process as in Example 13, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the resistivity was 2.2Mcm.
  • Example 15 40 wt% of alkali-free aluminosilicate glass powder was added to 60 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.6%
  • the porosity was 0.4%
  • the specific resistance was 1.9Mcm.
  • Example 16 the mixed powder composition and the manufacturing process were the same as those in Example 15, except that the sintering temperature was different. That is, 40 wt% of alkali-free aluminosilicate glass powder was added to 60 wt% of magnesia in the same composition and process as in Example 15, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the specific resistance was 1.9Mcm.
  • Example 17 20 wt% of low alkali aluminosilicate glass powder and 10 wt% of alkali free aluminosilicate glass powder were added to 70 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.8%
  • the porosity was 0.2%
  • the specific resistance was 1.6Mcm.
  • Example 18 a low alkali aluminosilicate glass powder and 15 wt% alkali-free aluminosilicate glass powder were added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.7%
  • the porosity was 0.3%
  • the specific resistance was 1.6Mcm.
  • Example 19 10 wt% of low alkali aluminosilicate glass powder and 20 wt% of alkali free aluminosilicate glass powder were added to 70 wt% of magnesia, and the alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
  • the relative density was 99.5%
  • the porosity was 0.5%
  • the specific resistance was 1.8Mcm.
  • the addition amount (ie, x of Formula 1) of the low alkali aluminosilicate glass powder and / or the glass powder which is an alkali free aluminosilicate glass powder is added in an amount of 10 to 40 wt%, particularly preferably. 10-30 wt%.
  • Figure 3 is a graph of the change in relative density according to the addition ratio and sintering temperature when low alkali aluminosilicate glass powder is added to magnesia as embodiments of the present invention.
  • the low alkali aluminosilicate glass powder at a sintering temperature of 1350 °C or more it can be seen that the relative density is more than 95% at 10 ⁇ 40wt%.
  • the relative densities were similar at 20 to 40 wt%, but the relative density also increased as the specific gravity of the low alkali aluminosilicate glass powder was increased at 1300 ° C, but the same at 1350 ° C but almost the same at 1400 ° C. It can be seen that the relative density decreases as the specific gravity of the low alkali aluminosilicate glass powder increases.
  • FIG. 4 is a graph showing changes in relative density according to addition ratio and sintering temperature when alkali-free aluminosilicate glass powder is added to magnesia as another embodiment of the present invention.
  • the relative density is also increased.
  • the relative density is more than 95% at 10 to 40wt% at the sintering temperature of 1400 ° C.
  • a solid electrolyte layer composition (e.g., "123" of FIG. 1) of a conventional stabilized zirconia (YSZ) composition and an insulating layer of the insulator composition according to the present invention (e.g., " 140 ") were laminated and cofired, and the heterojunction properties of these layers were observed.
  • YSZ stabilized zirconia
  • FIG. 5 is a laminate of an insulating layer made of a composition in which 20 wt% of calcium aluminosyl case glass powder is added to a magnesia and a solid electrolyte layer of a stabilized zirconia (YSZ) composition and co-fired at 1350 ° C. Crystal phase analysis (XRD, X-ray diffraction analysis) is shown.
  • the solid electrolyte composition is a zirconia crystal phase to which yttria (Y 2 0 3 ) is added, and the insulator composition is formed of a forsterite (Mg 2) formed by reaction of magnesia and glass powder in addition to the magnesia (MgO) main phase. It can be seen that SiO 4 ) secondary phase was produced.
  • Mg 2 forsterite
  • the insulating layer (B) made of the composition according to the present invention has a very good heterojunction without a delamination with the solid electrolyte layer (A) of YSZ composition. It can be confirmed that it has excellent adhesion.
  • the insulator composition according to the present invention is excellent in airtightness and electrical insulation as an insulating layer in application to the oxygen sensor, and in particular, by providing excellent adhesion and thermal conductivity with the solid electrolyte layer, Durability can be improved.
  • the powder characteristics such as the average particle size, distribution, and specific surface area of the composition powder, the purity of the raw material, the amount of impurity addition, and the heat treatment conditions vary slightly within a normal error range. It can be quite natural for one of ordinary skill in the art to be there.
  • the insulator composition according to the present invention may be applied to the oxygen sensor of FIG. 1, which is attached to each surface of the solid electrolyte layer, the solid electrolyte layer and the measurement electrode facing the exhaust gas and the atmosphere.

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Abstract

Disclosed is an insulator composition for an oxygen sensor having excellent airtightness and electric insulation as an insulation layer, and excellent adhesiveness to a solid electrolyte layer. The insulator composition for an oxygen sensor according to the present invention comprises magnesia, and sodium aluminosilicate glass and/or calcium aluminosilicate glass as a sintering aid.

Description

[규칙 제26조에 의한 보정 13.11.2012]　산소센서용 절연체 조성물 및 이를 이용한 산소센서 [Correction according to Rule 26. 13.11.2012] 절연 Insulator composition for oxygen sensor and oxygen sensor using the same
본 발명은 산소센서용 절연체 조성물에 관한 것으로, 특히 절연층으로서의 기밀성과 전기 절연성이 우수하며, 고체전해질층과의 우수한 부착성을 갖는 산소센서용 절연체 조성물에 관한 것이다.The present invention relates to an insulator composition for an oxygen sensor, and more particularly to an insulator composition for an oxygen sensor that is excellent in airtightness and electrical insulation as an insulating layer and has excellent adhesion to a solid electrolyte layer.
또한, 본 발명은 상기 절연체 조성물을 이용한 산소센서에 관한 것이다.The present invention also relates to an oxygen sensor using the insulator composition.
일반적으로 자동차의 엔진은 공기와 연료의 혼합비율인 공연비에 따라 엔진의 출력, 연료 소비량 및 배기 가스량이 변하므로, 항상 최적의 공연비를 유지하도록 제어하는 것이 필요하다. 특히 이러한 효율적인 제어를 통해 에너지 절감 및 유해 배기가스의 저감이 달성된다. 이러한 공연비는 자동차의 엔진에서 배출되는 배기가스 중에 포함되어 있는 산소의 함량을 측정함으로써 얻어지는데, 이러한 측정에는 통상적으로 산소센서가 사용된다.In general, since the engine of an automobile changes the output, fuel consumption and exhaust gas amount of the engine according to the air-fuel ratio, which is a mixture ratio of air and fuel, it is necessary to control the engine to maintain an optimum air-fuel ratio at all times. In particular, such efficient control results in energy savings and reduction of harmful emissions. This air-fuel ratio is obtained by measuring the content of oxygen contained in the exhaust gas emitted from the engine of the vehicle, the oxygen sensor is usually used for such a measurement.
이러한 산소센서는 상기 배기가스 중의 산소 함량에 따라 가변되어 발생하는 내부의 양단 전압을 엔진 제어장치인 ECU(Electronic Control Unit)로 보내고 ECU에서는 산소센서로부터 전송받은 상기 전압 데이터를 기초로 엔진으로 유입되는 연료 공급량을 조절하여 공연비를 제어하게 된다. The oxygen sensor transmits the internal both ends of the voltage generated according to the oxygen content of the exhaust gas to the ECU (Electronic Control Unit), which is an engine control device, and the ECU flows into the engine based on the voltage data received from the oxygen sensor. The air-fuel ratio is controlled by adjusting the fuel supply amount.
산소센서는 튜브형 및 평판형 등 여러 종류가 있으나, 최근에는 평판형 산소센서가 많이 이용되고 있다. 평판형 산소센서는 튜브형에 비해 크기를 작게할 수 있으며 센서의 동작개시 시간을 단축시킬 수 있는 이점이 있다. 이러한 평판형 산소센서는 독일특허공개공보 제DE2907032 A1호(1980. 8. 28 공개), 국제특허출원공개공보 제WO 1998/30984호(1998. 7. 16 공개) 등에 잘 개시되어 있다.There are many kinds of oxygen sensors such as tube type and flat type, but recently, flat type oxygen sensors have been used. The flat plate type oxygen sensor can have a smaller size than the tube type and can shorten the time to start the sensor. Such a plate-type oxygen sensor is well disclosed in DE2907032 A1 (published on August 28, 1980) and WO 1998/30984 (published on July 16, 1998).
도 1은 일반적인 평판형 산소센서의 구조를 개략적으로 도시한다. 1 schematically shows a structure of a general flat plate type oxygen sensor.
도 1을 참조하면, 일반적인 평판형 산소센서(100)는 알루미나 등의 기판(170) 상에 센서부(120)와, 이와 전기 절연층(140)으로 연결된 히터부(140)를 포함하여 구성된다.Referring to FIG. 1, the general flat plate type oxygen sensor 100 includes a sensor unit 120 on a substrate 170 such as alumina, and a heater unit 140 connected to the electrical insulating layer 140. .
센서부(120)는 고체전해질층(123)을 사이에 두고 상호 대향하도록 배치된 측정전극(122) 및 기준전극(124)을 포함한다. 또한, 상기 기준전극(124)의 하부에는 (기준)대기가 흐르는 기준채널(127)을 갖는 고체전해질층(125)이 위치되며, 상기 측정전극(122)의 상단은 다공성 산화물막인 보호층(121)으로 코팅된다. 상기 고체전해질층들(123, 125)은 산소이온 전도성을 가지며 일반적으로 안정화 지르코니아(Yttria Stabilized Zirconia: YSZ) 조성으로 된다.The sensor unit 120 includes a measurement electrode 122 and a reference electrode 124 disposed to face each other with the solid electrolyte layer 123 interposed therebetween. In addition, a solid electrolyte layer 125 having a reference channel 127 through which (reference) air flows is positioned below the reference electrode 124, and an upper end of the measurement electrode 122 is a protective layer that is a porous oxide film ( 121). The solid electrolyte layers 123 and 125 have oxygen ion conductivity and generally have a stabilized zirconia (YSZ) composition.
이러한 구조에서 상기 측정전극(122)은 배기가스를 대면하고 상기 기준전극(124)은 (기준)대기를 대면하므로, 이로써 상기 양 전극 간에 전위차가 발생하게 되고 이러한 전압을 검출하여 배기가스 내의 산소 함량을 검출한다.In this structure, since the measuring electrode 122 faces the exhaust gas and the reference electrode 124 faces the (reference) atmosphere, an electric potential difference is generated between the two electrodes, thereby detecting such a voltage, and thus the oxygen content in the exhaust gas. Is detected.
또한, 상기 히터부(13)는 발열체, 즉 저항가열체(142)를 포함하여 상기 산소센서의 동작 가능한 온도(예를 들어, 450~900℃)로 가열함으로써 상기 센서부(120)의 작동이 신속하게 이루어지도록 한다.In addition, the heater unit 13 includes a heating element, that is, a resistance heating element 142, the operation of the sensor unit 120 by heating to the operating temperature of the oxygen sensor (for example, 450 ~ 900 ℃) Make it happen quickly.
한편, 상기 절연층(140)은 일반적으로 알루미나(Al2O3) 조성으로 된다. 그런데, 이러한 알루미나(Al2O3) 조성체는 고체 전해질층(125)의 안정화 지르코니아(YSZ) 조성체와의 상이한 소결거동 특성을 가져 열팽창계수 보상을 위하여 불가피하게 다공체로 형성될 수 밖에 없다. 이러한 다공성으로 인해 배기가스가 기준채널(127) 내의 기준대기로 쉽게 확산되어 이를 오염시키므로, 센서부(120)의 측정값이 불안정해지고 히터부의 손상을 야기한다는 치명적인 문제점을 갖는다.On the other hand, the insulating layer 140 is generally made of alumina (Al 2 O 3 ) composition. However, such an alumina (Al 2 O 3 ) composition has a different sintering behavior than that of the stabilized zirconia (YSZ) composition of the solid electrolyte layer 125, so that the alumina (Al 2 O 3 ) composition is inevitably formed as a porous body to compensate for the thermal expansion coefficient. Due to the porosity, since the exhaust gas easily diffuses into the reference atmosphere in the reference channel 127 and contaminates it, the measurement value of the sensor unit 120 becomes unstable and causes a fatal problem that causes damage to the heater unit.
이러한 문제점을 개선하기 위하여 상기 제WO 1998/30984호에서는 알루미나 등의 결정성 비금속 물질과 알칼리토 실리케이트 유리로 된 유리 형성 물질로 구성된 조성물을 개시한다. 이러한 조성물은 유리의 연화특성을 이용하여 압축응력에 따른 소성변형을 제어하고 기밀성이 우수한 절연층을 형성할 수 있으며, 이로써 알루미나와 안정화 지르코니아 간의 상이한 소결거동과 열팽창계수가 보상될 수 있게 된다.In order to remedy this problem, WO 1998/30984 discloses a composition composed of a crystalline nonmetallic material such as alumina and a glass forming material of alkaline earth silicate glass. Such a composition can control the plastic deformation according to the compressive stress and form an insulating layer having excellent airtightness by using the softening property of the glass, thereby compensating for the different sintering behavior and coefficient of thermal expansion between alumina and stabilized zirconia.
그러나, 의도하는 특성의 절연층을 형성하기 위해서는 알루미나 등의 결정성 비금속 물질의 입도가 d50＜0.4㎛로 미세한 분말을 사용하여야 하며, 알칼리토 실리케이트 유리로 된 유리형성물질도 50wt%로 다량 사용함에 따라 절연층의 열전도도가 저하되면서 산소센서 제품 수명이 제한된다는 문제가 있다.However, in order to form an insulating layer of intended characteristics, a fine powder having a particle size of d 50 <0.4 μm of crystalline nonmetallic materials such as alumina should be used, and a large amount of glass forming material made of alkaline earth silicate glass is used at 50 wt%. Accordingly, there is a problem that the lifetime of the oxygen sensor is limited as the thermal conductivity of the insulating layer decreases.
따라서, 환경규제의 강화로 인해 평판형 산소센서 소자의 채용이 급증하는 추세속에서 높은 신뢰성을 확보하기 위하여 상기에서 설명한 요구 조건이 모두 만족되는 새로운 절연층 조성물의 개발이 요구된다.Therefore, in order to secure high reliability in the trend of the adoption of a flat plate type oxygen sensor element due to the strengthening of environmental regulations, the development of a new insulating layer composition that satisfies all the above-described requirements is required.
이에, 본 발명은 상기와 같은 문제점을 해결하기 위해 창안된 것으로, 본 발명의 목적은 기밀성과 전기 절연성이 우수하며 고체전해질층과의 우수한 부착성을 갖는 산소센서용 절연체 조성물을 제공하기 위한 것이다.Accordingly, the present invention was devised to solve the above problems, and an object of the present invention is to provide an insulator composition for an oxygen sensor having excellent airtightness and electrical insulation and excellent adhesion with a solid electrolyte layer.
이와 같은 목적을 달성하기 위한 본 발명의 일 관점에 의한 산소센서용 절연체 조성물은 마그네시아와, 소결조제로서 소듐 알루미노실리케이트 유리 및 칼슘 알루미노실리케이트 유리 중 하나 이상을 포함할 수 있다.Insulator composition for an oxygen sensor according to an aspect of the present invention for achieving the above object may include one or more of magnesia, sodium aluminosilicate glass and calcium aluminosilicate glass as a sintering aid.
이때, 상기 소결조제의 함량은 절연체 조성물 총량대비 10~40wt%, 바람직하게는 10~30wt%일 수 있다.At this time, the content of the sintering aid may be 10 ~ 40wt%, preferably 10 ~ 30wt% relative to the total amount of the insulator composition.
또한, 상기 소듐 알루미노실리케이트 유리의 조성은 다음 함량의 성분들을 포함할 수 있다:In addition, the composition of the sodium aluminosilicate glass may include components in the following contents:
Na2O 4~6wt%Na 2 O 4 ~ 6wt%
Al2O3 2~4wt%Al2O3                       2 ~ 4wt%
SiO2 90~94wt%.SiO2                                            90-94 wt%.
또한, 상기 칼슘 알루미노실리케이트 유리의 조성은 다음 함량의 성분들을 포함할 수 있다:In addition, the composition of the calcium aluminosilicate glass may include components of the following contents:
CaO 7~9wt%CaO 7 ~ 9wt%
Al2O3 15~18wt%Al2O3                       15 ~ 18wt%
SiO2 64~71wt%SiO2                                            64 ~ 71wt%
B2O3 7~9wt%.B2O3                       7-9 wt%.
또한, 상기 절연체 조성물의 소성온도는 1300~1500℃의 범위로 될 수 있다.In addition, the firing temperature of the insulator composition may be in the range of 1300 ~ 1500 ℃.
또한, 본 발명의 다른 일 관점에 의한 산소센서는 고체전해질층과, 상기 고체전해질층의 각 일면에 각각 부착되며 배기가스를 대면하는 측정전극과 대기를 대면하는 기준전극을 포함하여 상기 측정전극 및 기준전극 간의 전위차를 검출하여 산소농도를 감지하는 센서부와; 상기 센서부의 하면에 일체로 접합되고, 마그네시아와 소결조제로서 소듐 알루미노실리케이트 유리 및 칼슘 알루미노실리케이트 유리 중 하나 이상을 포함하는 절연체 조성물로 되고 상기 고체전해질층과 접합되는 절연층과, 상기 절연층 내부에 매립된 발열체를 포함하여 상기 센서부를 가열하는 히터부를 포함할 수 있다.In addition, the oxygen sensor according to another aspect of the present invention comprises a solid electrolyte layer, a measurement electrode attached to each surface of the solid electrolyte layer, respectively, the measurement electrode facing the exhaust gas and the reference electrode facing the atmosphere and A sensor unit for detecting oxygen concentration by detecting a potential difference between the reference electrodes; An insulating layer which is integrally bonded to the lower surface of the sensor part and is made of an insulator composition comprising at least one of sodium aluminosilicate glass and calcium aluminosilicate glass as magnesia and a sintering aid and bonded to the solid electrolyte layer; Including a heating element embedded therein may include a heater unit for heating the sensor unit.
도 1은 일반적인 평판형 산소센서의 개략구조도.1 is a schematic structural diagram of a general flat plate type oxygen sensor.
도 2는 본 발명의 일 실시예에 따른 산화물혼합법에 의한 제조공정 흐름도.Figure 2 is a flow chart of the manufacturing process by the oxide mixing method according to an embodiment of the present invention.
도 3은 본 발명의 실시예들로서 마그네시아에 저알칼리 알루미노실리케이트 유리분말을 첨가하였을 때의 첨가비율과 소결온도에 따른 상대밀도의 변화 그래프.Figure 3 is a graph of the change in relative density according to the addition ratio and sintering temperature when low alkali aluminosilicate glass powder is added to magnesia as embodiments of the present invention.
도 4는 본 발명의 다른 실시예들로서 마그네시아에 무알칼리 알루미노실리케이트 유리분말을 첨가하였을 때의 첨가비율과 소결온도에 따른 상대밀도의 변화 그래프.Figure 4 is a graph of the change in relative density according to the addition ratio and sintering temperature when the alkali-free aluminosilicate glass powder is added to magnesia as another embodiment of the present invention.
도 5는 본 발명에 따라 마그네시아에 칼슘알루미노실리케이스 유리분말이 20wt% 첨가된 조성물로 된 절연층과 안정화 지르코니아(YSZ) 조성의 고체전해질층을 적층하여 1350℃에서 동시소성한 적층물의 결정상분석(XRD, X-선 회절분석).FIG. 5 is a crystal phase analysis of a laminate co-fired at 1350 ° C. by stacking an insulating layer made of a composition in which calcium aluminosyl case glass powder is added to magnesia and a solid electrolyte layer of a stabilized zirconia (YSZ) composition according to the present invention. (XRD, X-ray diffraction analysis).
도 6은 도 5의 적층물의 주사전자현미경(FE-SEM) 사진.6 is a scanning electron microscope (FE-SEM) photograph of the laminate of FIG.
본 발명은 전술한 평판형 산소센서(예컨대, 도 1의 "100")에 있어서 절연층(예컨대, 도 1의 "140")으로서 유효하게 사용가능한 절연체 조성물에 관한 것이다. 이를 위해서는 상기 절연체 조성물에 우수한 기밀성 및 절연저항이 요구되며, 이러한 특성을 갖기 위한 요건으로서는 95% 이상의 상대밀도와 1MΩㆍcm 이상의 비저항을 가져야 한다.The present invention relates to an insulator composition that can be effectively used as an insulating layer (eg, "140" in FIG. 1) in the aforementioned flat plate oxygen sensor (eg, "100" in FIG. 1). For this purpose, excellent airtightness and insulation resistance are required for the insulator composition, and as a requirement for having such characteristics, the insulator composition should have a relative density of 95% or more and a specific resistance of 1 MΩ · cm or more.
이에, 본 발명자들은 산소센서용 절연체 조성물로서 마그네시아(MgO) 조성이 전술한 종래의 알루미나 조성을 대체할 수 있음을 알아냈다. 알루미나의 열전도도가 28~32W/(m*K)인데 반해, 마그네시아는 45~60W/(m*K)로서 알루미나에 비해 2배 정도 우수하다. 즉, 이러한 마그네시아 조성은 고체전해질층(예컨대, 도 1의 "125")의 안정화 지르코니아(Yttria Stabilized Zirconia: YSZ) 세라믹과 열팽창계수가 비슷하면서도 열전도도가 높다. Accordingly, the present inventors found that the magnesia (MgO) composition can replace the conventional alumina composition as the insulator composition for the oxygen sensor. The thermal conductivity of alumina is 28 ~ 32W / (m * K), while magnesia is 45 ~ 60W / (m * K), which is twice as good as alumina. That is, the magnesia composition has a similar thermal expansion coefficient and high thermal conductivity to Yttria Stabilized Zirconia (YSZ) ceramic of the solid electrolyte layer (eg, “125” in FIG. 1).
특히, 본 발명자들은 이러한 마그네시아(MgO)에 소결조제로 알칼리 알루미노실리케이트 및/또는 무알칼리 알루미노실리케이트 유리분말을 첨가하여 제조하는 경우, 고체전해질층과 동시 소성이 가능하고, 열전도도, 절연 및 소결 특성이 우수함을 알아냈다.In particular, the inventors of the present invention, when the alkali aluminosilicate and / or alkali-free aluminosilicate glass powder is added to the magnesia (MgO) as a sintering aid, it is possible to co-fire with the solid electrolyte layer, thermal conductivity, insulation and It was found that the sintering characteristics were excellent.
따라서, 이와 같은 본 발명에 의한 산소센서용 절연체 조성물의 조성식은 다음 식 1과 같다:Therefore, the composition formula of the insulator composition for an oxygen sensor according to the present invention is as follows:
(100-x)MgO ＋ x유리분말 (식 1)(100-x) MgO + x glass powder (Equation 1)
이때, x는 wt% 단위이고 상기 유리분말은 저알칼리 알루미노실리케이트 유리 분말 또는 무알칼리 알루미노실리케이트 유리 분말로 된다. 이들 분말의 입도는 1~2㎛ 범위로 됨이 바람직하다.In this case, x is a wt% unit and the glass powder is a low alkali aluminosilicate glass powder or an alkali free aluminosilicate glass powder. The particle size of these powders is preferably in the range of 1 to 2 µm.
또한, 상기 저알칼리 알루미노실리케이트 유리 분말 조성물은 소듐 알루미노실리케이트가 될 수 있으며, 다음 성분을 포함한다. 이때, 각 wt%는 전체 저알칼리 알루미노실리케이트 유리 분말 조성물 총량 대비이다:In addition, the low alkali aluminosilicate glass powder composition may be sodium aluminosilicate, and includes the following components. Wherein each wt% is relative to the total low alkali aluminosilicate glass powder composition:
Na2O 4~6wt%Na 2 O 4 ~ 6wt%
Al2O3 2~4wt%Al2O3                   2 ~ 4wt%
SiO2 90~94wt%.SiO2                                    90-94 wt%.
특히, 상기 저알칼리 알루미노실리케이트 유리 분말 조성물의 성분들은 다음의 조성비를 갖는 것이 바람직하다. 이때, 각 wt%는 전체 저알칼리 알루미노실리케이트 유리 분말 조성물 총량 대비이다:In particular, the components of the low alkali aluminosilicate glass powder composition preferably have the following composition ratio. Wherein each wt% is relative to the total low alkali aluminosilicate glass powder composition:
Na2O 5.3wt%Na 2 O 5.3wt%
Al2O3 3.0wt%Al2O3                   3.0wt%
SiO2 91.7wt%.SiO2                   91.7 wt%.
또한, 상기 무알칼리 알루미노실리케이트 유리 조성물은 칼슘 알루미노실리케이트가 될 수 있으며, 다음을 포함한다. 이때, 각 wt%는 전체 무알칼리 알루미노실리케이트 유리 분말 조성물 총량 대비이다:In addition, the alkali-free aluminosilicate glass composition may be calcium aluminosilicate, and includes the following. Wherein each wt% is relative to the total alkali free aluminosilicate glass powder composition:
CaO 7~9wt%CaO 7 ~ 9wt%
Al2O3 15~18wt%Al2O3                   15 ~ 18wt%
SiO2 64~71wt%SiO2                                    64 ~ 71wt%
B2O3 7~9wt%.B2O3                   7-9 wt%.
특히, 상기 무알칼리 알루미노실리케이트 유리 분말 조성물의 성분들은 다음의 조성비를 갖는 것이 바람직하다. 이때, 각 wt%는 전체 무알칼리 알루미노실리케이트 유리 분말 조성물 총량 대비이다:In particular, the components of the alkali-free aluminosilicate glass powder composition preferably have the following composition ratio. Wherein each wt% is relative to the total alkali free aluminosilicate glass powder composition:
CaO 8.3wt%CaO 8.3wt%
Al2O3 16.7wt%Al2O3                   16.7wt%
SiO2 67.0wt%SiO2                   67.0wt%
B2O3 8.0wt%.B2O3                   8.0 wt%.
또한, 본 발명에 의한 산소센서용 절연체 조성물은 산화물혼합법, 닥터블레이드 등의 후막인쇄법 등을 포함한 해당 분야에 공지된 여러 제조방법으로 제조될 수 있다. 특히, 도 2는 이러한 산화물혼합법에 의한 제조공정을 설명하지만, 본 발명의 제조방법은 이에 한정되는 것은 아니다.In addition, the insulator composition for an oxygen sensor according to the present invention may be prepared by various manufacturing methods known in the art, including an oxide mixing method and a thick film printing method such as a doctor blade. In particular, Fig. 2 illustrates a manufacturing process by the oxide mixing method, but the manufacturing method of the present invention is not limited thereto.
도 2를 참조하면, 먼저 소결조제로서 상기 저알칼리 알루미노실리케이트 또는 무알칼리 알루미노실리케이트 유리를 밀링하여 1~2㎛ 정도의 입도가 되도록 분쇄한다(S202).Referring to FIG. 2, first, the low alkali aluminosilicate or alkali free aluminosilicate glass is milled as a sintering aid to grind to a particle size of about 1 to 2 μm (S202).
그리고, 이렇게 제조된 소결조제를 마그네시아(MgO)에 첨가하여 알코올을 용매로 밀링하여 혼합 및 분쇄한다(S204). 이후, 상기 분쇄된 혼합물을 건조시킨다(S206). Then, the sintering aid prepared as described above is added to magnesia (MgO), and the alcohol is milled with a solvent to be mixed and ground (S204). Thereafter, the ground mixture is dried (S206).
이후, 상기 건조된 혼합분말을 소정 압력으로 성형하고(예를 들어, 직경 15㎜ 몰드로 100MPa의 압력을 가하여 성형), 1300~1500℃의 온도에서 2시간 동안 소결한다(S208).Thereafter, the dried mixed powder is molded at a predetermined pressure (for example, molded by applying a pressure of 100 MPa to a mold having a diameter of 15 mm), and sintered at a temperature of 1300 to 1500 ° C. for 2 hours (S208).
그리고, 이렇게 제조된 소결체는 상대밀도 측정을 통하여 소결 특성을 평가한 후, 그 양면에 은(Ag), 백금(Pt) 및 팔라듐(Pd)을 포함한 해당 분야에 공지된 물질로 되는 전극 및 리드선을 부착하고 800℃에서 1시간 동안 열처리하여 산소센서용 절연체를 제조한다(S210). The sintered body thus prepared was evaluated for sintering characteristics through relative density measurements, and then, electrodes and lead wires made of materials known in the art including silver (Ag), platinum (Pt), and palladium (Pd) were formed on both surfaces thereof. Attached and heat treated at 800 ℃ for 1 hour to prepare an insulator for oxygen sensor (S210).
이하, 본 발명의 바람직한 실시예들을 첨부한 도면을 참조하며 상세히 설명한다. 다만, 본 발명이 하술하는 실시예들은 본 발명의 전반적인 이해를 돕기 위하여 제공되는 것이며, 본 발명은 하기 실시예들로만 한정되는 것은 아니다.Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. However, the embodiments described below are provided to help the overall understanding of the present invention, and the present invention is not limited to the following examples.
실시예 1Example 1
본 실시예 1에서는 마그네시아 90wt%에 저알칼리 알루미노실리케이트 유리분말 10wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 이렇게 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 1, 10 wt% of a low alkali aluminosilicate glass powder was added to 90 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The mixed powder thus dried was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered at a temperature of 1350 ° C. for 2 hours using an electric furnace.
제조된 소결체는 상대밀도 측정을 통하여 소결 특성을 평가하고, 양면에 은(Ag)전극과 은(Ag) 리드선을 부착하고 800℃에서 1시간 동안 열처리한 후 700℃에서 비저항 측정을 통하여 절연특성을 평가하였다.The manufactured sintered body was evaluated for its sintering characteristics by measuring its relative density, and the silver (Ag) electrode and silver (Ag) lead wire were attached to both surfaces, and heat-treated at 800 ° C for 1 hour, and then the insulation characteristics were measured at 700 ° C through specific resistance measurement. Evaluated.
그 결과, 상대밀도는 97.4%, 기공율은 2.6%, 비저항은 1.1Mcm로 나타났다.As a result, the relative density was 97.4%, the porosity was 2.6%, and the specific resistance was 1.1Mcm.
실시예 2Example 2
본 실시예 2는 혼합분말 조성 및 제조공정이 실시예 1과 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 1과 동일한 조성 및 공정으로 마그네시아 90wt%에 저알칼리 알루미노실리케이트 유리분말 10wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 2, the mixed powder composition and the manufacturing process are the same as those in Example 1, except that the sintering temperature is different. That is, 10 wt% of a low alkali aluminosilicate glass powder was added to 90 wt% of magnesia in the same composition and process as in Example 1, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 98.1%, 기공율은 1.9%, 비저항은 1.4Mcm로 나타났다.As a result, the relative density was 98.1%, the porosity was 1.9%, and the specific resistance was 1.4Mcm.
실시예 3Example 3
본 실시예 3에서는 마그네시아 80wt%에 저알칼리 알루미노실리케이트 유리분말 20wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 3, 20 wt% of a low alkali aluminosilicate glass powder was added to 80 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.7%, 기공율은 0.3%, 비저항은 1.8Mcm로 나타났다.As a result, the relative density was 99.7%, the porosity was 0.3%, and the specific resistance was 1.8Mcm.
실시예 4Example 4
본 실시예 4는 혼합분말 조성 및 제조공정이 실시예 3과 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 3과 동일한 조성 및 공정으로 마그네시아 80wt%에 저알칼리 알루미노실리케이트 유리분말 20wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 4, the mixed powder composition and the manufacturing process are the same as those in Example 3, except that the sintering temperature is different. That is, in the same composition and process as in Example 3, 20 wt% of a low alkali aluminosilicate glass powder was added to 80 wt% of magnesia, mixed, pulverized and dried, and then the dried mixed powder was molded. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 2.0Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the resistivity was 2.0 Mcm.
실시예 5Example 5
본 실시예 5는 마그네시아 70wt%에 저알칼리 알루미노실리케이트 유리분말 30wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 5, a low alkali aluminosilicate glass powder was added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 1.5Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the specific resistance was 1.5Mcm.
실시예 6Example 6
본 실시예 6은 혼합분말 조성 및 제조공정이 실시예 5와 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 5와 동일한 조성 및 공정으로 마그네시아 70wt%에 저알칼리 알루미노실리케이트 유리분말 30wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 6, the mixed powder composition and manufacturing process were the same as those in Example 5, except that the sintering temperature was different. That is, 30 wt% of a low alkali aluminosilicate glass powder was added to 70 wt% of magnesia in the same composition and process as in Example 5, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.5%, 기공율은 0.5%, 비저항은 1.1Mcm로 나타났다.As a result, the relative density was 99.5%, the porosity was 0.5%, and the specific resistance was 1.1Mcm.
실시예 7Example 7
본 실시예 7은 마그네시아 60wt%에 저알칼리 알루미노실리케이트 유리분말 40wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 7, 40 wt% of low alkali aluminosilicate glass powder was added to 60 wt% of magnesia, and the alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 1.2Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the specific resistance was 1.2Mcm.
실시예 8Example 8
본 실시예 8은 혼합분말 조성 및 제조공정이 실시예 7과 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 7과 동일한 조성 및 공정으로 마그네시아 60wt%에 저알칼리 알루미노실리케이트 유리분말 40wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 8, the mixed powder composition and the manufacturing process were the same as those in Example 7, except that the sintering temperature was different. That is, in the same composition and process as in Example 7, 40 wt% of a low alkali aluminosilicate glass powder was added to 60 wt% of magnesia, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.3%, 기공율은 0.7%, 비저항은 0.9Mcm로 나타났다.As a result, the relative density was 99.3%, the porosity was 0.7%, and the specific resistance was 0.9Mcm.
실시예 9Example 9
본 실시예 9는 마그네시아 90wt%에 무알칼리 알루미노실리케이트 유리분말 10wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 9, 10 wt% of alkali-free aluminosilicate glass powder was added to 90 wt% of magnesia, and alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 92.5%, 기공율은 7.5%, 비저항은 0.7Mcm로 나타났다.As a result, the relative density was 92.5%, the porosity was 7.5%, and the specific resistance was 0.7Mcm.
실시예 10Example 10
본 실시예 10은 혼합분말 조성 및 제조공정이 실시예 9와 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 9와 동일한 조성 및 공정으로 마그네시아 90wt%에 무알칼리 알루미노실리케이트 유리분말 10wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 10, the mixed powder composition and the manufacturing process were the same as those in Example 9, except that the sintering temperature was different. That is, in the same composition and process as in Example 9, 10 wt% of alkali-free aluminosilicate glass powder was added to 90 wt% of magnesia, mixed, pulverized and dried, and then the dried mixed powder was molded. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 96.5%, 기공율은 3.5%, 비저항은 0.9Mcm로 나타났다.As a result, the relative density was 96.5%, the porosity was 3.5%, and the specific resistance was 0.9Mcm.
실시예 11Example 11
본 실시예 11은 마그네시아 80wt%에 무알칼리 알루미노실리케이트 유리분말 20wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 11, 20 wt% of alkali-free aluminosilicate glass powder was added to 80 wt% of magnesia, and alcohol was mixed and pulverized in a ball mill to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 95.7%, 기공율은 4.3%, 비저항은 1.0Mcm로 나타났다.As a result, the relative density was 95.7%, the porosity was 4.3%, and the specific resistance was 1.0Mcm.
실시예 12Example 12
본 실시예 12는 혼합분말 조성 및 제조공정이 실시예 11과 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 11과 동일한 조성 및 공정으로 마그네시아 80wt%에 무알칼리 알루미노실리케이트 유리분말 20wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 12, the mixed powder composition and the manufacturing process were the same as those in Example 11, except that the sintering temperature was different. That is, 20 wt% of alkali-free aluminosilicate glass powder was added to 80 wt% of magnesia in the same composition and process as in Example 11, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 98.6%, 기공율은 1.4%, 비저항은 1.3Mcm로 나타났다.As a result, the relative density was 98.6%, the porosity was 1.4%, and the specific resistance was 1.3Mcm.
실시예 13Example 13
본 실시예 13은 마그네시아 70wt%에 무알칼리 알루미노실리케이트 유리분말 30wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 13, an alkali free aluminosilicate glass powder was added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.The prepared sintered body was evaluated for the sintering characteristics and the insulating characteristics in the same process as in Example 1.
그 결과, 상대밀도는 99.5%, 기공율은 0.5%, 비저항은 2.1Mcm로 나타났다.As a result, the relative density was 99.5%, the porosity was 0.5%, and the specific resistance was 2.1 Mcm.
실시예 14Example 14
본 실시예 14는 혼합분말 조성 및 제조공정이 실시예 13과 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 13과 동일한 조성 및 공정으로 마그네시아 70wt%에 무알칼리 알루미노실리케이트 유리분말 30wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 14, the mixed powder composition and the manufacturing process were the same as those in Example 13, except that the sintering temperature was different. That is, 30 wt% of alkali-free aluminosilicate glass powder was added to 70 wt% of magnesia in the same composition and process as in Example 13, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 2.2Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the resistivity was 2.2Mcm.
실시예 15Example 15
본 실시예 15는 마그네시아 60wt%에 무알칼리 알루미노실리케이트 유리분말 40wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 15, 40 wt% of alkali-free aluminosilicate glass powder was added to 60 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.6%, 기공율은 0.4%, 비저항은 1.9Mcm로 나타났다.As a result, the relative density was 99.6%, the porosity was 0.4%, and the specific resistance was 1.9Mcm.
실시예 16Example 16
본 실시예 16은 혼합분말 조성 및 제조공정이 실시예 15와 동일하나, 다만 소결온도만 상이하게 실시하였다. 즉, 실시예 15와 동일한 조성 및 공정으로 마그네시아 60wt%에 무알칼리 알루미노실리케이트 유리분말 40wt%를 첨가하여 혼합 및 분쇄하여 건조시킨 후, 건조된 혼합분말을 성형하였다. 다만, 이 성형체를 1400℃의 온도에서 2시간 동안 소결하였다.In Example 16, the mixed powder composition and the manufacturing process were the same as those in Example 15, except that the sintering temperature was different. That is, 40 wt% of alkali-free aluminosilicate glass powder was added to 60 wt% of magnesia in the same composition and process as in Example 15, followed by mixing, pulverizing and drying to form a dried mixed powder. However, this molded body was sintered at a temperature of 1400 ° C. for 2 hours.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 1.9Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the specific resistance was 1.9Mcm.
실시예 17Example 17
본 실시예 17은 마그네시아 70wt%에 저알칼리 알루미노실리케이트 유리분말 20wt%와 무알칼리 알루미노실리케이트 유리분말 10wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 17, 20 wt% of low alkali aluminosilicate glass powder and 10 wt% of alkali free aluminosilicate glass powder were added to 70 wt% of magnesia, and the alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.8%, 기공율은 0.2%, 비저항은 1.6Mcm로 나타났다.As a result, the relative density was 99.8%, the porosity was 0.2%, and the specific resistance was 1.6Mcm.
실시예 18Example 18
본 실시예 18은 마그네시아 70wt%에 저알칼리 알루미노실리케이트 유리분말 15wt%와 무알칼리 알루미노실리케이트 유리분말 15wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 18, a low alkali aluminosilicate glass powder and 15 wt% alkali-free aluminosilicate glass powder were added to 70 wt% of magnesia, and alcohol was mixed with a solvent in a ball mill and pulverized to dry. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.7%, 기공율은 0.3%, 비저항은 1.6Mcm로 나타났다.As a result, the relative density was 99.7%, the porosity was 0.3%, and the specific resistance was 1.6Mcm.
실시예Example 19 19
본 실시예 19는 마그네시아 70wt%에 저알칼리 알루미노실리케이트 유리분말 10wt%와 무알칼리 알루미노실리케이트 유리분말 20wt%를 첨가하여 볼밀에서 알코올을 용매로 혼합 및 분쇄하여 건조시켰다. 건조된 혼합분말을 지름이 15mm 원형의 금속몰드에서 100MPa의 압력으로 성형한 후, 전기로를 이용하여 1350℃의 온도에서 2시간 동안 소결하였다.In Example 19, 10 wt% of low alkali aluminosilicate glass powder and 20 wt% of alkali free aluminosilicate glass powder were added to 70 wt% of magnesia, and the alcohol was mixed and pulverized in a ball mill and dried. The dried mixed powder was molded at a pressure of 100 MPa in a 15 mm diameter metal mold, and then sintered for 2 hours at a temperature of 1350 ° C. using an electric furnace.
제조된 소결체는 실시예 1과 동일한 공정으로 소결 특성과 절연특성을 각각 평가하였다.In the manufactured sintered compact, the sintering characteristics and the insulating characteristics were evaluated in the same manner as in Example 1.
그 결과, 상대밀도는 99.5%, 기공율은 0.5%, 비저항은 1.8Mcm로 나타났다.As a result, the relative density was 99.5%, the porosity was 0.5%, and the specific resistance was 1.8Mcm.
이상과 같은 실시예 1~19의 결과는 아래 표 1과 같이 정리된다:The results of Examples 1 to 19 described above are summarized as in Table 1 below:
표 1
실시예 조성(wt%) 소결온도(℃) 상대밀도(%) 기공율(%) 비저항(ohmcm)
MgO 저알칼리 알루미노실리케이트 유리분말 무알칼리 알루미노실리케이트 유리분말
1 90 10 0 1350 97.4 2.6 1.1M
2 90 10 0 1400 98.1 1.9 1.4M
3 80 20 0 1350 99.7 0.3 1.8M
4 80 20 0 1400 99.8 0.2 2.0M
5 70 30 0 1350 99.8 0.2 1.5M
6 70 30 0 1400 99.5 0.5 1.1M
7 60 40 0 1350 99.8 0.2 1.2M
8 60 40 0 1400 99.3 0.7 0.9M
9 90 0 10 1350 92.5 7.5 0.7M
10 90 0 10 1400 96.5 3.5 0.9M
11 80 0 20 1350 95.7 4.3 1.0M
12 80 0 20 1400 98.6 1.4 1.3M
13 70 0 30 1350 99.5 0.5 2.1M
14 70 0 30 1400 99.8 0.2 2.2M
15 60 0 40 1350 99.6 0.4 1.9M
16 60 0 40 1400 99.8 0.2 1.9M
17 70 20 10 1350 99.8 0.2 1.6M
18 70 15 15 1350 99.7 0.3 1.6M
19 70 10 20 1350 99.5 0.5 1.8M
Table 1
Example Composition (wt%) Sintering Temperature (℃) Relative Density (%) Porosity (%) Resistivity (ohmcm)
MgO Low Alkali Aluminosilicate Glass Powder Alkali free aluminosilicate glass powder
One 90 10 0 1350 97.4 2.6 1.1M
2 90 10 0 1400 98.1 1.9 1.4M
3 80 20 0 1350 99.7 0.3 1.8M
4 80 20 0 1400 99.8 0.2 2.0M
5 70 30 0 1350 99.8 0.2 1.5M
6 70 30 0 1400 99.5 0.5 1.1M
7 60 40 0 1350 99.8 0.2 1.2M
8 60 40 0 1400 99.3 0.7 0.9M
9 90 0 10 1350 92.5 7.5 0.7M
10 90 0 10 1400 96.5 3.5 0.9M
11 80 0 20 1350 95.7 4.3 1.0M
12 80 0 20 1400 98.6 1.4 1.3M
13 70 0 30 1350 99.5 0.5 2.1M
14 70 0 30 1400 99.8 0.2 2.2M
15 60 0 40 1350 99.6 0.4 1.9M
16 60 0 40 1400 99.8 0.2 1.9M
17 70 20 10 1350 99.8 0.2 1.6M
18 70 15 15 1350 99.7 0.3 1.6M
19 70 10 20 1350 99.5 0.5 1.8M
상기 표 1에 나타난 바와 같이, 본 발명에 따라 마그네시아에 저알칼리 알루미노실리케이트 유리분말 및/또는 무알칼리 알루미노실리케이트 유리분말을 10~40wt% 첨가한 절연체 조성물을 1350℃ 또는 1400℃에서 소결하였을 때, 상대밀도는 92.5~99.8%이고 비저항은 0.7~2.2MΩㆍcm로서 우수한 절연특성을 나타내었다. As shown in Table 1 above, when the insulator composition to which low alkali aluminosilicate glass powder and / or alkali free aluminosilicate glass powder is added to magnesia according to the present invention is sintered at 1350 ° C or 1400 ° C , The relative density was 92.5 ~ 99.8% and the specific resistance was 0.7 ~ 2.2MΩ · cm.
일반적으로 산소센서 절연층의 우수한 기밀성과 절연저항을 위한 95%이상의 상대밀도와 1MΩㆍcm 이상의 비저항을 가져야 한다. 이러한 조건은 저알칼리 알루미노실리케이트 유리분말 및/또는 무알칼리 알루미노실리케이트 유리분말로 되는 유리분말의 첨가량(즉, 상기 식 1의 x)이 10~40wt% 첨가될 때 만족되며, 특히 바람직하게는 10~30wt%이다.In general, it should have a relative density of 95% or more and a resistivity of 1 MΩ · cm or more for excellent airtightness and insulation resistance of the oxygen sensor insulation layer. These conditions are satisfied when the addition amount (ie, x of Formula 1) of the low alkali aluminosilicate glass powder and / or the glass powder which is an alkali free aluminosilicate glass powder is added in an amount of 10 to 40 wt%, particularly preferably. 10-30 wt%.
도 3은 본 발명의 실시예들로서 마그네시아에 저알칼리 알루미노실리케이트 유리분말을 첨가하였을 때의 첨가비율과 소결온도에 따른 상대밀도의 변화 그래프이다.Figure 3 is a graph of the change in relative density according to the addition ratio and sintering temperature when low alkali aluminosilicate glass powder is added to magnesia as embodiments of the present invention.
도 3을 참조하면, 소결온도 1350℃ 이상에서 저알칼리 알루미노실리케이트 유리분말은 10~40wt%에서 모두 상대밀도가 95% 이상되는 것을 확인할 수 있다. 또한, 20~40wt%에서 상대밀도는 모두 비슷한 수치를 나타내나, 소결온도가 1300℃에서 저알칼리 알루미노실리케이트 유리분말의 비중이 높아질수록 상대밀도도 올라가나 1350℃에서는 거의 같아지다가 1400℃에서는 반대로 저알칼리 알루미노실리케이트 유리분말의 비중이 높아질수록 상대밀도가 낮아지는 것을 알 수 있다.Referring to Figure 3, the low alkali aluminosilicate glass powder at a sintering temperature of 1350 ℃ or more it can be seen that the relative density is more than 95% at 10 ~ 40wt%. In addition, the relative densities were similar at 20 to 40 wt%, but the relative density also increased as the specific gravity of the low alkali aluminosilicate glass powder was increased at 1300 ° C, but the same at 1350 ° C but almost the same at 1400 ° C. It can be seen that the relative density decreases as the specific gravity of the low alkali aluminosilicate glass powder increases.
도 4는 본 발명의 다른 실시예들로서 마그네시아에 무알칼리 알루미노실리케이트 유리분말을 첨가하였을 때의 첨가비율과 소결온도에 따른 상대밀도의 변화 그래프이다.FIG. 4 is a graph showing changes in relative density according to addition ratio and sintering temperature when alkali-free aluminosilicate glass powder is added to magnesia as another embodiment of the present invention.
도 4를 참조하면, 대체적으로 소결온도가 올라갈수록 상대밀도도 높아지며, 특히, 소결온도 1400℃에서는 10~40wt%에서 모두 상대밀도가 95% 이상되는 것을 확인할 수 있다.Referring to FIG. 4, as the sintering temperature is increased, the relative density is also increased. In particular, it can be seen that the relative density is more than 95% at 10 to 40wt% at the sintering temperature of 1400 ° C.
또한, 산소센서로의 적용을 위하여 통상의 안정화 지르코니아(YSZ) 조성의 고체전해질층 조성물(예컨대, 도 1의 "123")과 본 발명에 의한 절연체조성물로 된 절연층(예컨대, 도 1의 "140")을 적층하고 동시소성한 후, 이들 층의 이종접합 특성을 관찰하였다.In addition, a solid electrolyte layer composition (e.g., "123" of FIG. 1) of a conventional stabilized zirconia (YSZ) composition and an insulating layer of the insulator composition according to the present invention (e.g., " 140 ") were laminated and cofired, and the heterojunction properties of these layers were observed.
즉, 도 5는 본 발명에 따라 마그네시아에 칼슘알루미노실리케이스 유리분말이 20wt% 첨가된 조성물로 된 절연층과 안정화 지르코니아(YSZ) 조성의 고체전해질층을 적층하여 1350℃에서 동시소성한 적층물의 결정상분석(XRD, X-선 회절분석)을 나타낸다. 도 5를 참조하면, 고체전해질 조성물은 이트리아(Y203)가 첨가된 지르코니아 결정상이며, 절연체조성물은 마그네시아(MgO) 주상 이외에 마그네시아와 유리분말이 서로 반응에 의해 형성된 포스테라이트(Mg2SiO4) 2차상이 생성된 것을 확인할 수 있다.That is, FIG. 5 is a laminate of an insulating layer made of a composition in which 20 wt% of calcium aluminosyl case glass powder is added to a magnesia and a solid electrolyte layer of a stabilized zirconia (YSZ) composition and co-fired at 1350 ° C. Crystal phase analysis (XRD, X-ray diffraction analysis) is shown. Referring to FIG. 5, the solid electrolyte composition is a zirconia crystal phase to which yttria (Y 2 0 3 ) is added, and the insulator composition is formed of a forsterite (Mg 2) formed by reaction of magnesia and glass powder in addition to the magnesia (MgO) main phase. It can be seen that SiO 4 ) secondary phase was produced.
도 6은 도 5의 적층물의 주사전자현미경(FE-SEM) 사진이다. 도 6을 참조하면, 1350℃에서 동시소성한 결과, 본 발명에 의한 조성물로 된 절연층(B)는 YSZ 조성의 고체전해질층(A)과 박리현상(Delamination) 없이 이종접합이 매우 양호하게 되어 우수한 부착성을 가짐을 확인할 수 있다.6 is a scanning electron microscope (FE-SEM) photograph of the laminate of FIG. 5. Referring to FIG. 6, as a result of co-firing at 1350 ° C., the insulating layer (B) made of the composition according to the present invention has a very good heterojunction without a delamination with the solid electrolyte layer (A) of YSZ composition. It can be confirmed that it has excellent adhesion.
이상과 같이, 본 발명에 의한 절연체 조성물은 산소센서로의 적용에 있어 절연층으로서의 기밀성과 전기 절연성이 우수하며, 특히 고체전해질층과의 우수한 부착성 및 열전도도를 부여함으로써, 산소센서의 신뢰성 및 내구성을 향상시킬 수 있다.As described above, the insulator composition according to the present invention is excellent in airtightness and electrical insulation as an insulating layer in application to the oxygen sensor, and in particular, by providing excellent adhesion and thermal conductivity with the solid electrolyte layer, Durability can be improved.
이상, 상술된 본 발명의 구현예 및 실시예에 있어서, 조성분말의 평균입도, 분포 및 비표면적과 같은 분말특성과, 원료의 순도, 불순물 첨가량 및 열처리 조건에 따라 통상적인 오차범위 내에서 다소 변동이 있을 수 있음은 해당 분야에서 통상의 지식을 가진 자에게는 지극히 당연하다.In the above-described embodiments and examples of the present invention, the powder characteristics such as the average particle size, distribution, and specific surface area of the composition powder, the purity of the raw material, the amount of impurity addition, and the heat treatment conditions vary slightly within a normal error range. It can be quite natural for one of ordinary skill in the art to be there.
아울러 본 발명의 바람직한 구현예 및 실시예는 예시의 목적을 위해 개시된 것이며, 해당 분야에서 통상의 지식을 가진 자라면 누구나 본 발명의 사상과 범위 안에서 다양한 수정, 변경, 부가 등이 가능할 것이고, 이러한 수정, 변경, 부가 등은 특허청구범위에 속하는 것으로 보아야 한다. 일 예로서, 본 발명에 의한 절연체 조성물은 도 1의 산소센서에 적용될 수 있으며, 이러한 산소센서는 고체전해질층과, 상기 고체전해질층의 각 일면에 각각 부착되며 배기가스를 대면하는 측정전극과 대기를 대면하는 기준전극을 포함하여 상기 측정전극 및 기준전극 간의 전위차를 검출하여 산소농도를 감지하는 센서부와, 상기 센서부의 하면에 일체로 접합되고, 마그네시아와 소결조제로서 소듐 알루미노실리케이트 유리 및 칼슘 알루미노실리케이트 유리 중 하나 이상을 포함하는 절연체 조성물로 되고 상기 고체전해질층과 접합되는 절연층과, 상기 절연층 내부에 매립된 발열체를 포함하여 상기 센서부를 가열하는 히터부를 포함할 수 있다.In addition, preferred embodiments and embodiments of the present invention are disclosed for the purpose of illustration, anyone of ordinary skill in the art will be possible to various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications Changes, additions, and the like should be considered to be within the scope of the claims. As an example, the insulator composition according to the present invention may be applied to the oxygen sensor of FIG. 1, which is attached to each surface of the solid electrolyte layer, the solid electrolyte layer and the measurement electrode facing the exhaust gas and the atmosphere. A sensor unit for detecting an oxygen concentration by detecting a potential difference between the measuring electrode and the reference electrode, including a reference electrode facing the electrode, is integrally bonded to the lower surface of the sensor unit, and sodium aluminosilicate glass and calcium as a sintering aid It may include a heater unit for heating the sensor unit including an insulating layer comprising at least one of the aluminosilicate glass, the insulating layer bonded to the solid electrolyte layer, and a heating element embedded in the insulating layer.

Claims (7)

  1. 산소센서용 절연체 조성물에 있어서,In the insulator composition for oxygen sensor,
    마그네시아와, 소결조제로서 소듐 알루미노실리케이트 유리 및 칼슘 알루미노실리케이트 유리 중 하나 이상을 포함하는 것을 특징으로 하는 절연체 조성물.An insulator composition comprising magnesia and at least one of sodium aluminosilicate glass and calcium aluminosilicate glass as sintering aids.
  2. 제1항에 있어서,The method of claim 1,
    상기 소결조제의 함량은 절연체 조성물 총량대비 10~40wt%인 것을 특징으로 하는 절연체 조성물.The content of the sintering aid is an insulator composition, characterized in that 10 to 40wt% relative to the total amount of the insulator composition.
  3. 제1항에 있어서,The method of claim 1,
    상기 소결조제의 함량은 절연체 조성물 총량대비 10~30wt%인 것을 특징으로 하는 절연체 조성물.The content of the sintering aid is an insulator composition, characterized in that 10 ~ 30wt% relative to the total amount of the insulator composition.
  4. 제1항에 있어서,The method of claim 1,
    상기 소듐 알루미노실리케이트 유리의 조성은 다음 함량의 성분들을 포함하는 것을 특징으로 하는 절연체 조성물:The composition of the sodium aluminosilicate glass comprises components of the following content:
    Na2O 4~6wt%Na 2 O 4 ~ 6wt%
    Al2O3 2~4wt%Al2O3                   2 ~ 4wt%
    SiO2 90~94wt%.SiO2                                    90-94 wt%.
  5. 제1항에 있어서,The method of claim 1,
    상기 칼슘 알루미노실리케이트 유리의 조성은 다음 함량의 성분들을 포함하는 것을 특징으로 하는 절연체 조성물:The composition of the calcium aluminosilicate glass comprises the following contents of components:
    CaO 7~9wt%CaO 7 ~ 9wt%
    Al2O3 15~18wt%Al2O3                   15 ~ 18wt%
    SiO2 64~71wt%SiO2                                    64 ~ 71wt%
    B2O3 7~9wt%.B2O3                   7-9 wt%.
  6. 제1항에 있어서,The method of claim 1,
    상기 절연체 조성물의 소성온도는 1300~1500℃인 것을 특징으로 하는 절연체 조성물.The firing temperature of the insulator composition is 1300 ~ 1500 ℃ characterized in that the insulator composition.
  7. 고체전해질층과, 상기 고체전해질층의 각 일면에 부착되되 배기가스를 대면하는 측정전극과 대기를 대면하는 기준전극을 포함하여 상기 측정전극 및 기준전극 간의 전위차를 검출하여 산소농도를 감지하는 센서부와;Sensor unit for detecting the oxygen concentration by detecting a potential difference between the measurement electrode and the reference electrode including a solid electrolyte layer, a measurement electrode attached to each surface of the solid electrolyte layer, but facing the exhaust gas and a reference electrode facing the atmosphere Wow;
    상기 센서부의 하면에 일체로 접합되고, 제1항에 의한 절연체 조성물로 되고 상기 고체전해질층과 접합되는 절연층과, 상기 절연층 내부에 매립된 발열체를 포함하여 상기 센서부를 가열하는 히터부를 포함하는 산소센서.And a heater unit integrally bonded to a bottom surface of the sensor unit, the heater unit including the insulation layer formed of the insulator composition according to claim 1 and bonded to the solid electrolyte layer, and a heating element embedded in the insulation layer. Oxygen sensor.
PCT/KR2012/007830 2012-09-27 2012-09-27 Insulator composition for oxygen sensor, and oxygen sensor using same WO2014051176A1 (en)

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JP2005077127A (en) * 2003-08-28 2005-03-24 Kyocera Corp Oxygen sensor element
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