JPH0560726A - Measuring device of constituent in molten metal - Google Patents

Abstract

PURPOSE:To ensure a balanced state of divided voltage on a three-phase interface of a molten metal/a subelectrode/a solid electrolyte in a sensor element and to obtain a quick response and an excellent waveform in a measuring device of a constituent of a subelectrode type. CONSTITUTION:A measurement stabilizing means 28 containing a mixture oxide which has an oxide of an element to be measured and/or an inorganic compound containing the oxide of the element to be measured, as a main constituent, is provided between a sensor element 23 provided with a subelectrode and fireproof cement 27 supporting the sensor element 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a component in molten metal for measuring the concentration of solute elements such as aluminum and silicon contained in molten metal such as hot metal and molten steel.

[0002]

2. Description of the Related Art Conventionally, there is known an apparatus using a sensor element to which the technology of an oxygen concentration battery using a solid electrolyte is applied in order to measure an impurity element in a molten metal. In this component measuring device, as shown in FIG. 7 (A), a shell body 1 immersed in molten metal is formed by a solid electrolyte made of zirconium dioxide (ZrO ₂ ) or the like, and an oxygen potential is formed on the inner surface of the shell body 1. Powder and Mo for keeping temperature constant at the measurement temperature
A reference electrode 2 composed of a mixture of O ₂ powder and a mixture of Cr powder and Cr ₂ O ₃ powder is provided, and an oxide of the element to be measured to be measured and an oxide of the element to be measured to be measured are provided on the outer surface of the shell 1. A sub-electrode 3 made of a mixed oxide containing an inorganic compound containing an oxide of an element to be measured as a main component is provided, and the sensor element 4 is configured by this. In the sub-electrode 3, for example, the elements to be measured in the molten metal to be measured are Cr, Mn, Si and A.
In the case of 1 and P, Cr ₂ O ₃ and / or Cr ₂ O, respectively
A mixed oxide mainly composed of an inorganic compound containing an oxide of the element to be measured containing ₃ and a mixed oxide mainly composed of an inorganic compound containing an oxide of the element to be measured containing MnO and / or MnO, A mixed oxide containing an inorganic compound containing SiO ₂ and / or an oxide of an element to be measured containing SiO ₂ as a main component (for example, a mixture of ZrSiO ₄ and ZrO ₂ ),
A mixed oxide mainly composed of an inorganic compound containing an oxide of the element to be measured containing Al ₂ O ₃ and / or Al ₂ O ₃ (for example, a mixture of Al ₂ O ₃ and TiAl ₂ O ₅ ), P ₂
A mixed oxide containing an inorganic compound as a main component containing an oxide of an element to be measured including O ₅ and / or P ₂ O ₅ (for example, 3
(A mixture of CaO.P ₂ O ₅ and ZrO ₂ ). A potential difference measuring means 6 is provided between the sensor element 4 and the molten metal electrode 5. The reference numeral 7 is
A temperature measuring element having a thermocouple, which is connected to the temperature measuring means 8.

When measuring the concentration of the solute element in the molten metal with this device, the device is immersed in the molten metal, and the activity of the element to be measured in the molten metal is converted into an oxygen potential by the auxiliary electrode. .. Therefore, the solid electrolyte forming the shell body 1, the reference electrode 2 and the potential difference measuring means 6
Since the oxygen concentration cell is constituted by, the oxygen potential converted by the sub-electrode 3 appears as a potential difference detected by the solid electrolyte. And this potential difference corresponds to the concentration of the element to be measured in the molten metal,
As a result, the concentration of the metal element to be measured can be measured.

In other words, this conventional sub-electrode type component measuring device measures the oxygen partial pressure equilibrium at the three-phase interface of molten metal / sub-electrode / solid electrolyte, and the equilibrium reaction formula: M + O = MO
The solute element (M) is measured using (oxide of solute element), and the equilibrium constant K of this equilibrium reaction equation is uniquely determined by the temperature, and the equation: K = aMO / (hM · Po) ₂ ^1/2 ), where aMO is the activity of the oxide of the solute element to be measured in the auxiliary electrode, hM is the activity of the solute element to be measured, Po
₂ is the oxygen partial pressure at the three-phase interface). Therefore, when aMO is constant with temperature, or when it is expected that the temperature changes, hM can be uniquely obtained from Po ₂ and temperature (T).

By the way, such a sub-electrode type component measuring device is disclosed in Japanese Patent Laid-Open Nos. 61-142455 and 61-61.
As is known from JP-A-260155, etc., when putting this into practical use, as shown in FIG. 7 (B), the housing 10 of the tip opening attached to the probe body 9 is filled with the refractory cement 11, and The base end of each of the sensor element 4, the molten metal electrode 5, and the temperature measuring element 7 is a refractory cement 1
By embedding it in the housing 1, it is supported and also projected from the tip of the housing 10. The housing 1
0 is, for example, Al ₂ O ₃ system or Al ₂ O ₃ —SiO ₂
The refractory cement 11 is made of ceramics of
For example, it is made of Al ₂ O ₃ type or ZrSiO ₄ type cement.

[0006]

The inventor of the present invention has conducted extensive studies and experiments on the auxiliary electrode type component measuring device as described above, and as a result, has conducted experiments, and as a result, the housing 1 in the vicinity of the sensor element 4 has been investigated.
0, in particular, when the activity of the oxide of the same element as the element to be measured contained in the refractory cement 11 is significantly different from the activity of the oxide of the element to be measured in the oxide forming the sub-electrode 3. ,
For example, in the case of 1/20, it has been known that the response difference and the waveform defect due to the potential difference measuring means 6 occur.

That is, in such a sub-electrode type component measuring device, the activity of the oxide of the element to be measured in the sub-electrode is set to a constant value, and the equilibrium component at the three-phase interface of molten metal / sub-electrode / solid electrolyte is set. Since the element to be measured is quantified by measuring the pressure by using the above two equations, the sensor element 4
If the activity of the oxide of the element to be measured existing in the vicinity of is equal to or close to the activity of the oxide of the element to be measured in the sub-electrode, a wide area near the sensor element containing the molten metal However, the equilibrium arrival time is short because it is dominated by the oxide of the element to be measured having the same activity. However, according to the experiments of the present inventor, the activity of the oxide of the element to be measured in the vicinity of the sensor element 4, particularly on the surface of the refractory cement 11 is significantly higher than the activity of the oxide of the element to be measured in the sub-electrode. If they are different, the equilibrium at the three-phase interface of the molten metal / sub-electrode / solid electrolyte is disrupted, so that the sensor element 4 is affected to a considerable extent, which causes a delayed response and a waveform defect. Was confirmed.

[0008]

According to the present invention, the equilibrium state of the three-phase interface of molten metal / sub-electrode / solid electrolyte in the sensor element is ensured by a very simple structure, and a quick response and a good waveform are obtained. It is intended to provide a component measuring device capable of performing the above.

Therefore, the first means constituted by the present invention is as follows:
A housing having an opening at the tip, a refractory cement filled in the housing, and a sensor element supported by the refractory cement and protruding from the tip of the housing are provided, and the sensor element has oxygen ion conductivity. Contains a shell formed of a solid electrolyte, a reference electrode provided inside the shell, and an oxide of the element to be measured and / or an oxide of the element to be measured deposited on the outer surface of the shell. And a sub-electrode made of a mixed oxide containing an inorganic compound as a main component, the oxide of the element to be measured and / or the surface of the refractory cement at the tip of the housing and the protrusion of the sensor element and / or The point is that a measurement stabilizing means containing a mixed oxide whose main component is an inorganic compound containing an oxide of the element to be measured is provided.

The measurement stabilizing means is an oxide of the element to be measured deposited on the surface of the refractory cement at the tip of the housing and / or a mixed oxide containing an inorganic compound containing the oxide of the element to be measured as a main component. Or may be composed of an inorganic compound containing an oxide of the element to be measured and / or an oxide of the element to be measured fixed to the surface of the refractory cement at the tip of the housing. A molded product made of mixed oxides may be formed.

The second means constituted by the present invention is a housing having an open tip, a refractory cement filled in the housing, and a sensor supported by the refractory cement and protruding from the tip of the housing. The sensor element, the sensor element comprises a shell body formed of a solid electrolyte having oxygen ion conductivity, a reference electrode provided inside the shell body, and a coating applied to the outer surface of the shell body. In the case where the auxiliary electrode is composed of a mixed oxide whose main component is an inorganic compound containing an oxide of the element to be measured and / or an oxide of the element to be measured, the object to be measured is contained in the refractory cement at the tip of the housing. Add a mixed oxide whose main component is an inorganic compound containing an oxide of an element and / or an oxide of an element to be measured, and provide a measurement stabilizing means at least on the surface of the refractory cement. There is a point.

Further, according to the third means of the present invention, the sensor element supported by the tip of the housing and projected from the tip of the housing is formed of a solid electrolyte having oxygen ion conductivity. Main component is a shell, a reference electrode provided inside the shell, and an oxide of the element to be measured and / or an inorganic compound containing an oxide of the element to be measured deposited on the outer surface of the shell. And an inorganic electrode containing an oxide of the element to be measured and / or an oxide of the element to be measured between the tip surface of the housing and the protrusion of the sensor element. The point is that a measurement stabilizing means containing a mixed oxide containing a compound as a main component is provided.

In any one of the first to third means, in the mixed oxide mainly composed of the oxide of the element to be measured and / or the inorganic compound containing the oxide of the element to be measured in the sub-electrode. And the activity aMO of the oxide of the element to be measured, and the oxide of the element to be measured in the measurement stabilizing means and / or the mixed oxide mainly composed of the inorganic compound containing the oxide of the element to be measured. The relationship between the activity aCMO of the oxide of the element is 0.
It is preferable to configure in the range of 1 ≦ aCMO / aMO ≦ 2.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings.

In each of the embodiments described below, a cylindrical housing 22 is attached to the tip of a probe body 21 made of a paper tube or the like, and a sensor element 23, a molten metal electrode 24, a temperature measuring element are attached to the housing 22. 25 is supported and is projected from the tip of the housing 22. Reference electrode side lead wire 23 extending from the sensor element 23
a, a molten metal side lead wire 24 extending from the molten metal electrode 24
a, thermocouple lead wires 25a, 2 extending from the temperature measuring element 25
5b is a connector 2 through the inside of the housing 22.
Connected to 6.

The connector 26 is fixed so as to close the rear end of the housing 22, and is detachably fitted to a connecting means such as a plug inserted inside from the tail end side of the probe main body 21.

The housing 22 is filled with refractory cement 27. The refractory cement 27 holds the lead wires 23a, 24a, 25a and 25b by embedding and holds the sensor element 23 and the molten metal electrode 24. Temperature measuring element 2
The base end of 5 is embedded and supported. The housing 22 is made of, for example, Al ₂ O ₃ -based or Al ₂ O ₃ —SiO ₂ -based ceramics, and the refractory cement 27 is, for example,
Al ₂ O ₃ system, ZrSiO ₄ system, Al ₂ O ₃ -Si
It consists of O ₂ type cement.

The sensor element 23 is similar to the above-mentioned conventional example, and is made of zirconium dioxide (ZrO ₂ ).
A reference electrode for keeping the oxygen potential constant at the measurement temperature is provided on the inner surface of the shell body formed of a solid electrolyte made of, for example, while a sub-electrode is provided on the outer surface of the shell body. The reference electrode is made of, for example, a mixture of Mo powder and MoO ₂ powder or a mixture of Cr powder and Cr ₂ O ₃ powder, and the sub-electrode is the element to be measured in the molten metal, which is a measurement target. Oxide and / or a mixed oxide mainly composed of an inorganic compound containing an oxide of an element to be measured, and by coating or spot-coating such an oxide on the outer surface of the shell. Composed. For example, when the element to be measured in the molten metal to be measured is Cr, Mn, Si, Al, or P, the oxide forming the sub-electrode is Cr ₂ O, respectively.
Mainly mixed oxides containing an inorganic compound containing an oxide of the element to be measured containing ₃ and / or Cr ₂ O ₃ and an inorganic compound containing an oxide of the element to be measured containing MnO and / or MnO Mixed oxide as a component, SiO ₂ and / or a mixed oxide mainly composed of an inorganic compound containing an oxide of an element to be measured including SiO ₂ (for example, a mixture of ZrSiO ₄ and ZrO ₂ ), Al ₂ O ₃ And / or Al ₂ O ₃
Mixed oxides composed mainly of an inorganic compound containing an oxide of the element to be measured containing Al (eg, Al ₂ O ₃ and TiAl ₂ O
Mixture of _5), P ₂ O ₅ and / or P ₂ mixed oxides of the inorganic compound containing as a main component an oxide of O ₅ to be measured elements (e.g. a mixture of 3CaO · P ₂ O ₅ and ZrO ₂ ).

(First Embodiment) In the first embodiment shown in FIG. 1, the housing 22 has an opening at the front end, and a measurement stabilizing means 28 is provided on the surface of the refractory cement 27 facing the opening. The measurement stabilizing means 28 is an oxide of the same material as a mixed oxide containing an inorganic compound containing an oxide forming the sub-electrode of the sensor element 23 and / or an oxide of an element to be measured as a main component, and / or The refractory cement 2 is composed of a coating layer 29 such as a coating made of a mixed oxide whose main component is an inorganic compound containing an oxide of the element to be measured.
It is preferable that the surface of No. 7 is coated or spotted, but it is not always necessary to provide it on the entire surface of the refractory cement 27, and the three-phase interface of the molten metal / sub-electrode / solid electrolyte as described above is required. It suffices if it is provided on the surface portion of the refractory cement 27 that causes the imbalance.

(Second Embodiment) In the second embodiment shown in FIG. 2, the measurement stabilizing means 28 is an inorganic material containing an oxide constituting the sub-electrode of the sensor element 23 and / or an oxide of the element to be measured. A refractory cement 27 comprising a molded article 30 composed of a mixed oxide containing a compound as a main component and an oxide of the same material and / or an inorganic compound containing an oxide of an element to be measured as a main component. It is embedded and supported on the surface of. In this case as well, it is preferable to provide the molded product 30 on the entire surface of the refractory cement 27 in the same manner as described above, but it is not always necessary to provide it on the entire surface, and it is provided only at a specific place necessary for the purpose of the present invention. It's enough. At this time, by forming the holding hole 31 in the molded product 30,
The sensor element 23 (and / or the molten metal electrode 24 and / or the temperature measuring element 25) may be held.

(Third Embodiment) In the third embodiment shown in FIG. 3, the measurement stabilizing means 28 is an inorganic material containing an oxide constituting the sub-electrode of the sensor element 23 and / or an oxide of the element to be measured. The mixed oxide containing the compound as the main component and the cylindrical member 32 composed of the mixed oxide containing the same material and / or the oxide of the element to be measured as the main component of the inorganic compound, It is embedded and supported on the surface of the refractory cement 27 and surrounds the outer peripheral region of the sensor element 23 by the tubular body 32.

(Fourth Embodiment) In the fourth embodiment shown in FIG. 4, the measurement stabilizing means 28 is made of an additive material 33 added to the refractory cement 27 at the tip of the housing 22, and the additive material 33 is A mixed oxide mainly composed of an inorganic compound containing an oxide constituting an auxiliary electrode of the sensor element 23 and / or an oxide of an element to be measured and / or an oxide of the element to be measured It is composed of a mixed oxide containing an inorganic compound containing as a main component. The additive 33 may be added to the entire refractory cement 27, but for the purpose of the present invention, it may be added to at least a portion near the tip surface of the refractory cement 27.

(Fifth Embodiment) In the fifth embodiment shown in FIG. 5, the housing 22 is formed in a bottomed cylindrical shape having a bottom wall 22a for closing the front end thereof, and an insertion hole formed in the bottom wall 22a. The sensor element 23, the molten metal electrode 24, and the base end of the temperature measuring element 25 are supported. Further, a measurement stabilizing means 28 is provided on the surface of the bottom wall 22a, and the measurement stabilizing means 28 is an inorganic compound containing an oxide constituting the sub-electrode of the sensor element 23 and / or an oxide of the element to be measured. And a coating layer 34 such as a coating made of a mixed oxide containing the same material as the main component and / or an inorganic compound containing the oxide of the element to be measured as the main component. The coating layer 34 is preferably provided on the entire surface of the bottom wall 22a, but may be provided only at a specific place necessary for the purpose of the present invention.

(Other Embodiments) Measurement stabilizing means 28 of the present invention
As described above, is provided in order to eliminate the cause of disrupting the equilibrium of the three-phase interface of molten metal / sub-electrode / solid electrolyte. Therefore, various design changes and It can be improved. That is, in the present invention, a mixed oxide mainly composed of an inorganic compound containing an oxide constituting an auxiliary electrode and / or an oxide of an element to be measured and an oxide of the same material and / or an oxide of the element to be measured The measuring and stabilizing means 28 composed of a mixed oxide containing an inorganic compound as a main component is essentially the same as the measuring and stabilizing means 28 in the case where the housing 22 has an open end and the refractory cement 27 faces the sensor element 23. Stabilizer 28 is refractory cement 27
And the sensor element 23, and the housing 22 is formed in a bottomed shape with the bottom wall 22a, if the measurement stabilizing means 28 is provided between the bottom wall 22a and the sensor element 23. good.

(Preferred Example of Measurement Stabilizing Means) As a result of an experiment based on the present invention, the measurement stabilizing means 28 showed that the oxide of the element to be measured and / or the oxidation of the element to be measured in the sub-electrode of the sensor element 23 was oxidized. Activity a of the oxide of the element to be measured in the mixed oxide containing an inorganic compound as a main component
The activity aC of the oxide of the element to be measured in the mixed oxide mainly composed of MO and the oxide of the element to be measured in the measurement stabilizing means 28 and / or the inorganic compound containing the oxide of the element to be measured.
It was found that good results can be obtained by configuring the relationship with MO within the range of 0.1 ≦ aCMO / aMO ≦ 2.

(Experimental Example 1) An experiment for measuring Si in the hot metal was conducted by using the component measuring apparatus of the fourth embodiment shown in FIG.

The activity of the oxide of the element to be measured in the mixed oxide mainly composed of the oxide of the element to be measured and / or the inorganic compound containing the oxide of the element to be measured in the sub-electrode of the sensor element ( aMO) is 0.1 <aMO ≦ 1.
That is, when the sub-electrode is only SiO _2, aMO = 1, and the sub-electrode is a mixed oxide ZrSiO ₄ whose main component is an inorganic compound containing an oxide of the element to be measured including SiO _2.
In the case of the mixture of ZrO ₂ and ZrO ₂ , 0.1 <aMO <0.5.

Therefore, under the condition of 0.1 <aMO ≦ 0.5, the oxide of the element to be measured and / or the oxide of the element to be measured to be added to the Al ₂ O ₃ —SiO ₂ refractory cement is added. When an experiment was performed while adjusting the activity (aCMO) of the oxide of the element to be measured in the mixed oxide containing the inorganic compound as the main component, the results shown in the following table were obtained.

[0029]

[Table 1]

(Experimental Example 2) In conducting the same experiment as described above, the sub-electrode of the sensor element was used as a complex oxide of the element to be measured (ZrSiO ₄ ), or a complex oxide and oxide of the element to be measured. Mixture of (SiO ₂ + ZrSi
O ₄ ), and the activity of the oxide of the element to be measured in the mixed oxide mainly composed of the oxide of the element to be measured in the sub-electrode and / or the inorganic compound containing the oxide of the element to be measured. Under the condition that (aMO) is 0.5 ≧ aMO, A
Oxidation of the element to be measured in the mixed oxide mainly composed of the oxide of the element to be measured and / or the inorganic compound containing the oxide of the element to be measured to be added to the refractory cement of l ₂ O ₃ -SiO ₂ system When the experiment was performed while adjusting the activity (aCMO) of the product, the results shown in the following table were obtained.

[0031]

[Table 2]

In Tables 1 and 2 above, among the responsiveness,
○ means good response, △ means slightly good response, ×
In the case of poor response, among the waveform stability, ○ indicates that a stable waveform stable area can be obtained, △ indicates that an unstable waveform stable area can be obtained, and × indicates a waveform stable area. If not.

Therefore, as is clear from Experimental Examples 1 and 2, the conditions for satisfying both the responsiveness and the waveform stability are that the oxide and / or the oxide of the element to be measured in the sub-electrode of the sensor element 23 are used. The activity aMO of the oxide of the element to be measured in the mixed oxide containing an inorganic compound containing the oxide of the element to be measured as the main component, and the oxide of the element to be measured and / or the element to be measured in the measurement stabilizing means 28. Of the oxide of the element to be measured in the mixed oxide containing the inorganic compound containing the above oxide as the main component is expressed as 0.1 ≦ aCMO / aM.
It was confirmed that the range should be O ≦ 2.

(Experimental Result 1) Next, the inventor of the present invention uses the component measuring device set to aCMO / aMO = 1 in Experimental Example 1 described above to measure the Si concentration in the hot metal measured by the device. When it was tested whether the Si concentration determined by chemical analysis was correct, a good result as shown in FIG. 6 (A) was obtained. That is, in FIG. 6 (A),
The vertical axis represents the concentration of Si determined by the device of the present invention, the horizontal axis represents the concentration of Si quantified by chemical analysis from a sample obtained by sampling the hot metal, and a large number of ○ marks indicate each test result. There is.

Regarding this point, a similar test result obtained by using a conventional component measuring device having no measurement stabilizing means 28 is shown in FIG. 8 (A) and is used for comparison.

Therefore, as is clear from a comparison between FIG. 8A and FIG. 6A, in the conventional component measuring apparatus, the measured Si concentration has a large variation and is quantified from the sample. According to the present invention, the measured Si concentration shows an approximate value of the analytical value quantified from the sampling sample without variation, and the reliability of the measurement accuracy is high. You know that you promise sex.

(Experimental Result 2) The waveform of the electromotive force recorded during the test of Experimental Result 1 is shown in FIG. 6B.
The waveform recorded by the conventional device is as shown in FIG.

Therefore, as is clear from a comparison between FIG. 8B and FIG. 6B, in the conventional device, the response is slow and the waveform is not stable. ,
The response was quick and the waveform was stable, confirming its effect.

[0039]

According to the present invention, the equilibrium state of the three-phase interface of the molten metal / sub-electrode / solid electrolyte in the sensor element can be secured with an extremely simple structure, and a quick response and a good waveform are obtained. The effect is that you can.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a main part of the second embodiment of the present invention.

FIG. 3 is an enlarged vertical sectional view showing a main part of a third embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view showing a fifth embodiment of the present invention.

FIG. 6 shows test results of an experiment according to the invention,
(A) is a comparison diagram showing a correlation between a measured value according to the present invention and a silicon concentration quantified by chemical analysis of a sampling sample, and (B) is a waveform diagram showing an electromotive force in the device of the present invention.

FIG. 7 shows a component measuring device according to a conventional example, (A) is an explanatory view showing an enlarged sensor portion, and (B) is a longitudinal sectional view showing the device with the sensor portion assembled.

FIG. 8 shows test results of an experiment based on a conventional example,
(A) is a comparison diagram showing the correlation between the measured value according to the conventional example and the silicon concentration quantified by the chemical analysis of the sampling sample, and (B) is a waveform diagram showing the electromotive force in the conventional device.

[Explanation of symbols]

 21 probe body 23 sensor element 24 molten metal electrode 27 refractory cement 28 measurement stabilizing means

Claims (6)

[Claims] 1. A housing having an open end, a refractory cement filled in the housing, and a sensor element supported by the refractory cement and protruding from the tip of the housing, wherein the sensor element is oxygen. A shell body formed of a solid electrolyte having ionic conductivity,
Mixed oxidation composed mainly of a reference electrode provided inside the shell and an oxide of the element to be measured deposited on the outer surface of the shell and / or an inorganic compound containing the oxide of the element to be measured. A sub-electrode made of a material, the oxide of the element to be measured and / or the surface of the refractory cement at the tip of the housing and the protruding portion of the sensor element.
Alternatively, an apparatus for measuring components in molten metal is provided with a measurement stabilizing means containing a mixed oxide containing an inorganic compound containing an oxide of an element to be measured as a main component. 2. The measurement-stabilizing means is a mixed oxidation mainly composed of an oxide of the element to be measured and / or an inorganic compound containing the oxide of the element to be measured, which is deposited on the surface of the refractory cement at the tip of the housing. The component measuring apparatus for molten metal according to claim 1, wherein a coating layer made of a material is formed. 3. The measurement stabilizing means is an oxide of the element to be measured fixed on the surface of the refractory cement at the tip of the housing and / or a mixed oxide containing an inorganic compound containing the oxide of the element to be measured as a main component. The component measuring apparatus for molten metal according to claim 1, wherein the molded article is composed of 4. A housing having an opening at the tip, a refractory cement filled in the housing, and a sensor element supported by the refractory cement and protruding from the tip of the housing, wherein the sensor element is oxygen. A shell body formed of a solid electrolyte having ionic conductivity,
Mixed oxidation composed mainly of a reference electrode provided inside the shell and an oxide of the element to be measured deposited on the outer surface of the shell and / or an inorganic compound containing the oxide of the element to be measured. A sub-electrode composed of a substance, wherein the refractory cement at the housing tip portion is a mixed oxide containing an oxide of the element to be measured and / or an inorganic compound containing an oxide of the element to be measured as a main component. And a measuring and stabilizing means provided at least on the surface of the refractory cement. 5. A sensor element, which is supported by a tip portion of a housing and protrudes from the tip of the housing, is provided in a shell body formed of a solid electrolyte having oxygen ion conductivity, and provided inside the shell body. And a sub-electrode composed of a mixed oxide mainly composed of an oxide of the element to be measured and / or an inorganic compound containing the oxide of the element to be measured deposited on the outer surface of the shell. In the configured one,
A measurement stabilizing means containing an oxide of the element to be measured and / or a mixed oxide containing an inorganic compound containing the oxide of the element to be measured as a main component is provided between the tip surface of the housing and the protruding portion of the sensor element. An apparatus for measuring a component in molten metal, which is provided. 6. The activity aMO of the oxide of the element to be measured in the mixed oxide containing the oxide of the element to be measured in the sub-electrode and / or the inorganic compound containing the oxide of the element to be measured as a main component.
And the activity aCMO of the oxide of the element to be measured in the mixed oxide mainly composed of the oxide of the element to be measured and / or the inorganic compound containing the oxide of the element to be measured in the measurement stabilizing means. 6. The apparatus for measuring a component in a molten metal according to claim 1, 2, 3, 4 or 5, wherein: 0.1 ≦ aCMO / aMO ≦ 2.