WO1995018455A1 - Sintered thermistor body and thermistor device using it - Google Patents

Abstract

A high precision sintered thermistor body having stable characteristics. An oxide semiconductor for thermistor having a negative resistance-temperature characteristic is composed mainly of Mn and Co and contains 0.1-24 mol % Cu and Ti based on the total amount of the metal components.

Description

 TECHNICAL FIELD [0001] The present invention relates to a sintered body and a sintered apparatus using the same.

 The present invention relates to a thermistor sintered body and a thermostat using the same, and in particular, to a chip type thermostat, a disk type thermostat, and a thermometer which require high accuracy and high reliability as a temperature sensor. The present invention relates to an oxide semiconductor sintered body for a thermistor having a negative temperature coefficient of resistance, which is used for a crystal oscillation circuit for precision temperature compensation, an SMT type thermistor used for a surface mount circuit, and the like. Background art

 Conventionally, oxide semiconductors having a negative resistance temperature characteristic and having a negative resistance temperature characteristic include manganese (Μη), cobalt (Co), nickel (N i), copper ( It is an oxide sintered body consisting mainly of a cubic spinel type crystal phase of two or more components containing Cu), iron (Fe), etc., and further has a resistance value and a temperature coefficient of resistance value (hereinafter referred to as B It is known that aluminum or the like is added for the purpose of adjusting the constant. This B constant is expressed by the following equation.

B = (ln R ₂₅ -ln R _{C ()} ) / (1/298. 15-1 323. 15) where R ₂₅ : resistance value at 25 ° C

 R.g: Resistance value at 50 ° C

 In particular, a cubic spinel-type crystal phase is used for thermistor oxynitride sintered body with a specific resistance of several Ωcm to several kΩcm to adjust its resistance and B constant. Have been. However, the cubic spinel-type crystal phase is liable to undergo phase transformation to NaC1-type cubic during the process of undergoing heat history, such as the electrode baking process including the sintering process, and causes a reduction in the characteristic value yield.

In addition, in order to suppress the variation of the resistance value during the thermistor sintering, it has been attempted to construct a thermistor with a single cubic spinel-type crystal phase. (Eg, high-temperature storage, heat cycle test, etc.) The title is included.

 In addition, in conventional sintered bodies for thermistors, it is difficult to control the resistance value (or specific resistance value) while keeping the B constant almost constant with a constant shape. However, the situation was not sufficient.

 However, despite this situation, the reliability required for thermistors with negative resistance-temperature characteristics is increasing, and new characteristics such as a new B constant / resistance value are required. The demand for needs is increasing year by year. In recent years, sensors with high accuracy and high reliability (particularly high-temperature storage reliability) have been used for various sensors for preventing overcharge when charging Ni-Cd and Ni-IH batteries, and for temperature compensation of crystal oscillation circuits. There is a strong desire for the development of one mistake.

Therefore, various studies have been conducted.However, conventionally, in a thermistor sintered body composed of the same metal component system, the B constant is kept almost constant only by changing the metal component composition ratio. Summary of resistance i.e. _c invention it was not possible to significantly increase the resistance

 SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a single-component system is capable of developing a wide range of characteristics, has a high characteristic value yield, is highly accurate, and has a high-temperature storage reliability and is highly reliable. The purpose is to provide the body.

 A first feature of the present invention is that in a thermistor oxide semiconductor having a negative resistance-temperature characteristic, the constituent metal main component is composed of Mn and Co, and Cu and Ti are further represented by moles of a metal component. % To 0.1% to 24%.

 Desirably, the contents of the metal main components Mn and Co constituting the thermistor sintered body are 30 ≤ Mn ≤ 52, 46 ≤ Co

≤ 65.

 Preferably, in the thermistor sintered body, Mn, which is a metal main component, is used.

The content of Cu and Ti simultaneously added to Co should be 0.04 Cu ≤ 14, 0.06 ≤ Ti ≤ 10 in terms of mol% with respect to the metal component, respectively.

A second feature of the present invention is that, in the thermistor sintering suspension in which the main metal component is composed of Mn and Co and Cu and Ti are added, the sintering suspension is mainly cubic subbing. Na-Cl-type cubic crystal phase whose main metal component is Co, the cubic crystal phase whose main component is Cu, as well as the main phase of Cu At least one of the monoclinic crystal phases or the respective second phase crystal phases.

 The third feature of the present invention is that, as a metal component, Mn and Co are main components, and Cu and Ti are 0.1 to 40% by weight in total (0.1 to 44.4% for mol%). %) In the thermistor sintered body.

Desirably, the content of the metal components Mn and Co is 24≤Mn≤50 (23.2-52.3% for mol%) and 36≤Co in weight% with respect to the metal component, respectively. ≤ 60 fourth aspect of (mol% from 32.4 to 59.6% in the corresponding) and so as to _c present invention to the thermistor sintered of oxide semiconductors thermistor having a negative resistance-temperature characteristics The sintered body is formed into a disk-shaped or chip-shaped body to form a thermistor body, and electrodes are formed on at least one pair of both end edges of the thermistor body. The main component of the metal of the thermistor sintered body is composed of Mn and Co, and Cu and Ti are further contained in an amount of 〇.1 to 24% in terms of mol% total of the metal component.

 Desirably, the contents of the metal main components Mn and Co constituting the sintered body of the thermistor are 30≤Mn≤52 and 46≤Co≤65, respectively, in mol% with respect to the metal component. .

 Further, in this thermistor sintered body, the content of Cu and Ti simultaneously added to Mn and Co, which are the main components of the metal, is in mol% of the metal component.

 0.04 ≤ Cu u ≤ 14, 0.0.06 ≤ T i ≤ 10

It is characterized by being.

Desirably, in the thermistor sintered body, the main metal component is composed of Mn and Co, and in the thermistor sintered body to which Cu and Ti are added, the sintered body is mainly cubic spinel type. A Na C 1-type cubic crystal phase whose main metal component is Co, and a cubic crystal phase whose main component is Cu, as in the second phase. It is characterized by containing at least one of the monoclinic crystal phases or at least two of the second phase crystal phases. In the fifth aspect of the present invention, a thermistor sintered body made of an oxide semiconductor for a thermistor having a negative resistance temperature characteristic is formed into a disk shape or a chip shape to form a thermistor body. In a thermistor device in which electrodes are formed on at least one pair of both ends of the thermistor body, Mn and Co are main components as constituent metal components of the thermistor sintered body; And Ti in a total amount of 1 to 40% by weight.

Preferably, Mn is a metal component, the content of C o, 24≤Mn≤ 50 in weight percent about the metal components respectively, the _c present inventors, which is a 36≤ C o≤ 60 In a sintered body composed of Mn, Co, Cu, and Ti, various experiments were repeated with changing the composition ratio, and as a result, the specific resistance increased greatly with the increase of Ti. The B constant was found to increase only slightly.

 Therefore, according to the sintered body in which the metal main components are Mn and Co and the Ti and Cu are contained in a predetermined range, the B constant does not change or the change in the B constant is suppressed very small. Since the resistance value of the element can be changed significantly, it is easy to design the resistance value-B constant, which is effective for product series and diversification. According to the first aspect of the present invention, the structure of the thermistor sintered body is from a single-phase structure of a cubic spinel to a structure close to a single-phase structure, so that the variation in resistance value, B constant, coefficient of thermal expansion, and the like is extremely large. It is possible to provide a small and stable thermistor with high accuracy and high reliability at high temperature storage. That is, over the entire composition range of the metal components Mn, Co, Cu, and Ti, a cubic spinel-type single crystal phase or a cubic spinel-type single crystal phase is mainly formed by selecting the sintering temperature, and The second phase is a NaC1-type cubic crystal phase mainly composed of Co, a cubic crystal phase mainly composed of Cu, and a monoclinic crystal phase mainly composed of Cu. It is possible to obtain a sintered body structure containing at least one of each of the above or each of the second phase crystal phases.

In the thermistor sintered body of the present invention comprising a cubic spinel-type single crystal phase, the yield and precision of resistance can be improved extremely well.For example, it is necessary to suppress the fluctuation of the characteristic value to within 1%. Even at a certain stand, almost all falls within this range without the necessity of property selection, so that mass productivity can be improved. However, for example, in high-temperature storage reliability of 125 ° C, depending on the composition of Mn, Co, Cu, and Ti selected, at least the both edges of this sintered body of thermistor body are charged. It is necessary to allow a resistance change rate of several percent in a thermistor device formed with poles.

 On the other hand, in the second aspect of the present invention, the second phase is a Na C 1 type cubic crystal phase whose main metal component is Co as the second phase, and Cu is the main component. Thermistor having a sintered body structure containing at least one of the cubic crystal phase and the monoclinic crystal phase mainly composed of Cu, or at least two of the respective second phase crystal phases. In the sintered body, it is possible to control the rate of change of the resistance value to 1% or less when left at a high temperature of 125 ° C. This is because the cubic spinel-type crystal phase contains the above-mentioned crystal phase as the second phase, so that the second phase enters the crystal grain interface to form a stable structure, and the resistance change rate It is thought that it will be possible to keep the value small.

 In the third aspect of the present invention, by increasing or decreasing the amount of Cu, the specific resistance does not change significantly, but the B constant can be changed significantly.At the same time, the specific resistance value increases with the increase in the amount of Ti. We found that the B constant increased only slightly, but we found that the B constant increased only slightly.We focused on this fact, and as a metal component, Mn and Co were the main components, and Cu and Ti were 0.1 in total. By containing up to 40% by weight, a high yield in resistance value and B constant was achieved, and high-temperature storage reliability at a temperature of 100 ° C or lower could be obtained.

 Further, when the contents of the metal components M n and Co are 24 4 ≤M n ≤ 50 and 36 ≤ Co ≤ 60 in terms of the weight% of the metal component, respectively, The above characteristics were obtained.

Note that these compositions (sintered bodies) contain oxygen in addition to the metal components. According to the fourth and fifth aspects of the present invention, since the thermistor device is configured using the first to third thermistor sintered bodies, a highly accurate and high-temperature storage reliability highly reliable Evening equipment can be provided. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a flowchart showing a process of manufacturing a thermistor sintered body according to an embodiment of the present invention. FIG. 2 is a diagram of a process of manufacturing a thermistor using the thermistor sintered body.

 FIG. 3 is a quasi-ternary phase diagram showing a metal component mole% ratio composition region of the thermistor sintered body of the present invention.

 FIG. 4 is a manufacturing process diagram of an SMT thermistor using a thermistor sintered body according to the third embodiment of the present invention.

 FIG. 5 is an SMT thermistor using the thermistor sintered body according to the third embodiment of the present invention. FIG. 6 is a diagram illustrating a metal component weight% ratio composition of the thermistor sintered body according to the fourth embodiment of the present invention. Pseudo-ternary phase diagram showing the region Best mode for carrying out the invention

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 First, the manufacturing process of this thermistor sintered body will be described with reference to the flowchart of FIG.

First, commercially available trimanganese manganese oxide (Μη _η 0 ₄ ), cobalt oxide (Cο 0), copper oxide (Cu 0), and titanium oxide (Ti ₀₉ ) were weighed and mixed in a ball mill for 24 hours. After that, it was dehydrated and dried (step 1).

 Next, the dried powder is maintained at 850 to 950 ° C (900 ° C in this case) under atmospheric pressure and calcined for 2 hours. The calcined powder is ground again with a ball mill for 24 hours, Water-dried material was used as raw material powder (Step 2). At this time, each metal component was adjusted in the weighing step of Step 1 so as to have a molar percentage composition ratio of Mn 40.3 / Co50.7 / Cu3.0 / Ti6.0.

 1 wt% of polyvinyl alcohol was added to the raw material powder thus obtained, and molded into a disk having a diameter of 5 mm and a thickness of 1 mm using a mold. (Step 3). Finally, the molded body was baked by heating at a temperature of 1200 ° C. for 2 hours under a heating schedule capable of sufficiently removing polyvinyl alcohol (Step 4).

Electrodes were formed on both end surfaces of the thus obtained thermistor sintering plate using an Ag electrode paste, and a disk-shaped sampler was formed as shown in the process diagram in Fig. 2. — Miss evening formed.

 In other words, an Ag-based paste was applied to the upper and lower surfaces of this pellet 1 (Fig. 2 (a)) (Fig. 2 (b)), heated at 200 ° C for 5 minutes, pre-dried, and then 75 CTC For 10 minutes to form electrode 2 (FIG. 2 (c)).

 The resistance value of the disk-shaped sample obtained in this way was measured at 25 ° C, the specific resistance value was calculated from the geometric shape, and the resistance values at 25 ° C and 50 ° C were further calculated. The B constant was calculated.

The resistance R _{25 at} 25 ° C and the B constant B _{25/5 ()} at 25 ° C and 50 ° C were measured for a total of 1,000 disk-shaped thermistors on which electrodes were formed. The specific resistance p ₂₅ at 25 ° C calculated from the geometric shape is within the range of 325 Ω soil 3%, and the resistance value is in the range of R ₂₅ = 219 to 230 Q, B _{25 / & 0} = 3700 ± 1% Was within. Variations in the resistance values R _{25 and} B constant were sufficient for mass production of high precision thermistors. In addition, a high-temperature reliability test was conducted in which the disc-shaped thermistor with the electrodes formed was left in a thermostat at 125 ° C for 10 hours.

As test samples, the change rate of the resistance value R ₂₅ characteristics and sampling the total number 5◦ pieces from samples of the examination of B constant optionally, 125 ° C, 1000 hours left at high temperature before and after the resistance change rate and the B constant evaluated. The rate of change of the resistance value and the rate of change of the B constant were determined by the following formula.

(1000) (0) (0)

Resistance change rate ^{_{= (R 2 0 5 [R}} 25 Roh ^{/ R} 25

 (0)

5 R ₂₅ before leaving at high temperature

(1000)

R25 after left at high temperature for 1 hour at R25 ₂₅

B constant change rate = (B ⁽¹⁰⁰⁰⁾ B (0) B (0)

_B (o) B constant at 25 ° C / 5 ° C before leaving at high temperature

_B (1000)

 1 25 ° C after leaving at high temperature for 1 000 hours at 25 ° C Z5 ° C B constant

As a result of a pulmonary test such as this, a disk-shaped thermistor of The rate of change of resistance value after leaving at high temperature for 00 hours and the rate of change of B constant at 25 ° C and 50 ° C are extremely stable at +0.1 to 0.3% and +0.1 to 0.2%, respectively. Was confirmed.

 The resistance value and B constant of the obtained disk-shaped thermistor are extremely accurate, and in addition, the reliability at high temperature storage is high, and the stability is excellent. Investigate the cross-sectional structure of the sintered body and the crystal phase of the sintered body by X-ray diffraction.

 From the observation of the cross-sectional structure and the results of X-ray diffraction, it was clarified that the present sintered ceramics consisted of a cubic spinel-type crystal phase and a NaCl-type cubic-type crystal phase as the second phase. The main component of the second phase metal element was analyzed by an electron probe microanalyzer (EPMA). As a result, it was found to be a NaC1-type cubic crystal phase mainly composed of Co. Next, a second embodiment of the present invention will be described.

First the Sami scan evening sintered body, as in the first embodiment, a commercially available trimanganese tetraoxide (Mn ₃ 0 _4), cobalt oxide (C o 0), copper oxide (C u 0), oxide Titanium (Ti0.) Was weighed, mixed for 24 hours in a ball mill, and dehydrated and dried (step 1).

 Next, the dried powder is calcined at 9 ° C. for 2 hours under the atmospheric pressure, and the calcined powder is ground again by a ball mill for 24 hours, and the dehydrated and dried powder is used as a raw material powder (Step 2). ). Here, each metal component was adjusted in the weighing step of Step 1 so as to have a molar percentage composition ratio of Mn 49.0 / Co 47.4 / Cu2.4 Til.2.

 1 wt% of polyvinyl alcohol was added to the raw material powder obtained in this manner, and the mixture was molded into a cylindrical shape having a diameter of 3 Ommx and a thickness of 15 mm using a cold isostatic press (CHP). After degreasing according to a heating schedule that can sufficiently remove polyvinyl alcohol, baking was performed at 1250 for 1 hour. (Step 3).

From the cylindrical sintered body sample obtained in this manner, a slicer of 2 mm thick was cut out with a slicer, an Ag paste was printed on both sides of the wafer, and baked at 75 CTC. An electrode was formed in the same manner as in Example 1.

After the electrode is formed, the sintered body is again 0.85 mm x O. 85 mni by dicer. After cutting, a chip-shaped thermistor was prepared.

Thus mono- miss evening for obtained, together with obtaining the measured resistivity value resistance at 25 ° C, is 1 ◦ here _c of calculating the B constant than the resistance value of 25 ° C and 50 ° C Four sintered compacts were selected from each of the cylindrical sintered bodies, and a total of 40 sintered bodies were selected so that the characteristics and reliability variations of each part of the cylindrical sintered bodies could be evaluated by extracting from each of the cylindrical sintered bodies. 2000 chip-shaped thermistors on which Ag electrodes were formed were prepared from the bonded substrate.

Variations in the resistance value and the temperature coefficient of the resistance value of each chip-shaped semiconductor chip are within R ₂₅ = 686 Ω ± 3% and B _{25 / 5D} = 3690 ± 1%, respectively, which is an extremely good yield. In addition, high precision characteristics could be achieved. Geometry resistivity p ₂₅ at the calculated 25 ° C than the center value Atsuta at 248 Ω ♦ cm ± 3% within.

 The reliability of high temperature storage at 125 ° C for 1 000 hours is extremely good.

(1000) (0) (0)

Resistance change rate = (R ₂₅ -R ₂₅ ) / R ₂₅ ) is within ± 0.5%

B constant change rate = _(Β α000) — _B (0)) _{/ B} ° is within ± 0.2%

It was.

 The cross-sectional structure of the sintered body of the thermistor and the crystal phase of the sintered body by X-ray diffraction were examined.As a result, the sintered body consisted of a cubic spinel type crystal phase and a Na C 1 type cubic type crystal phase as the second phase. It became clear. The main component of the second phase metal element was analyzed by an electron probe microanalyzer (EPMA). As a result, it was found to be a NaC1-type cubic crystal phase mainly composed of Co.

 Next, a third embodiment of the present invention will be described.

 First, in this example, in order to clarify the relationship between the metal component composition of the sintered body and the high-temperature storage reliability, the EIAJ standard (standard conforming to the standard of chip laminated capacitors established by the Japan Electronic Machinery Manufacturers Association) was used. The results of the characteristics of the surface mount thermistor (hereinafter referred to as SMT thermistor) will be described in detail.

As shown in Table 1, the composition of each metal component was changed so that in Examples 1 and 2, After the sintering raw material powder was prepared in the same manner as shown, 10 wt% methylcellulose was added as a binder to the raw material powder thus obtained, and the mixture was sufficiently mixed to prepare a compound. Thereafter, a green sheet having a thickness of 0.6 to 1.1 mm was formed by an extrusion molding method.

Composition Metal composition ratio (mol%) Specific resistance m

 No. M n Co Cu Ti (K) s degree m ium $ Yield

1 43. 9 49. 6 5.3 1. 2 123 3840 CS, Col 0. 2 0 100 78

2 45. 0 45 7 2.2 7. 1 700 3710 CS, Col 0.7. 0. 3 100 78

3 40. 3 50 7 3.0 6.0 352 3700 CS, Col 0.4.0.2 100 78

4 49.0 47 4 2.4 1.2 248 3690 CS, Col 0.3 0.3 0.1 100 75

5 40.3 50 7 3.0 6.0 356 3646 CS, Col-0.4 0.2 0.2 75

6 38. 5 48 5 3.0.0 10.0 807 3720 CS, Col 0.8.0.3 0.3 100 75

7 39. 4 47 2 2.6 10.8 1040 3740 CS, Col 0.8.0.3 100 78

8 37.2 46 6 7.9 8.3 230 3390 CS, Coll, Cu2 0.7 0.7 0.5 100 75

9 35. 6 44 7 9. 8 9. 9 199 3490 CS.Col, Cu2 0.7.0.5 100 72

1 0 37.5 47 1 10.4 5. 0 86 3340 CS, Col, Cu2 0.6.0.4 100 70

1 1 39.7 49.9 9.8 0.6 60 3200 Cs 0.8.0.5 96 90

1 2 42. 0 52.8 3.2 2 205 3670 Cs 1.5 0.5 0.5 98 90

1 3 42. 9 53. 9 3. 2 130 3650 CS 0.6 0.6 0.5 98 90

1 4 40.3 50.7 3.0.0 6.0 350 3700 CS, Col 0.6.0.498 75

1 5 38. 6 48.5 2.9 10.0 805 3720 CS, Col 0.8.0.5 96 70

1 6 24.0 46.0 20.0 10.0 150 2900 CS, Cul 6.0.2.0 75 40.

1 7 34.6 43.4 7.0 15.0 1500 3600 CS, Cu2 5.0 2.0 0 80 40

1 8 30. 0 67. 0 0. 5 2.5 1050 4100 CS, Col 3.0 1. 0 80 40

1 9 28. 0 55.0 6.11.10 1100 3550 CS, Cu2 4.0.1.0 82 45

2 0 27. 0 65. 0 1.0 7.0 0 1200 4100 CS, Col 3.5 1.0 75 35

2 1 53.0 43.0 0.5.3.5 3500 4300 CS, Col 3.0.1.5 80 40

2 2 50.0 40.0 2.0.0 8.00 5000 4200 CS 3.0 1.0 78 89

2 3 39.2 44.3 4.7 11.8 850 3620 CS 6.0 1.5 95 85 Resistance change rate, B constant change rate, ± 3% target resistance yield, ± 1% target resistance Unit of value yield is% Where cs: cubic spinel phase

 Co 1: Co main component Na C 1 type cubic phase

 Cu 2: Cu main component cubic phase

 C u 1: C u main component monoclinic phase

 Further, the green sheet is cut into an appropriate size, degreased using a heating schedule capable of sufficiently removing the methylcellulose binder, and then 1 to 1300. Baking for 1-3 hours at C. (Step 3).

 A glass paste was screen-printed on both sides of the sheet-like fired body 1u (Fig. 4 (a)) obtained in this way, and baked at 80 CTC for 10 minutes to form the glass protective layers 3a and 3b. (See Fig. 4 (b)).

 Then, as shown in Fig. 4 (c), the sheet-like fired body 1u after the glass baking was cut into a strip of about 1.8mm by dicer as shown in Fig. 4 (c). Ag electrode 2 and bake it at 750 ° C for 10 minutes.

 Then, in order to further improve the solderability of the electrode part during circuit mounting, the Ni the plating layer 4 and the solder plating were applied to the strip-shaped thermistor structure on which the Ag electrode was baked by using the electric plating method. Layer 5 was formed (FIG. 4 (e)).

 The strip-shaped thermistor structure having the Ag electrode 2, the Ni plating layer 4, and the soldering layer 5 formed in this way is further cut by a dicer into a chip having a width of 1.15 to 1.2. (See Fig. 4 (f)) to create SMT thermistors with electrodes formed on at least a pair of both edges of the sintered body of thermistor (Figs. 5 (a) and (b)). See). The resistivity and the variation in resistance at 25 ° C in the thermistor thus obtained, the B constant at 25 ° C and 50 ° C, and 25 ° C in the high-temperature storage reliability test at 125 ° C for 1000 hours Rate of change of resistance value, 25 CZ50. The rate of change of the B constant of C was evaluated. Variations in resistance were evaluated at ± 3% and ± 1% resistance yields relative to the target value to determine whether mass production was possible. The results obtained are shown in Table 1 for each thermistor composition.

In Table 1, the high-temperature storage reliability test results of the SMT thermistors of the present invention shown in compositions No. 1 to No. 12 and No. 14 to No. o. Compared to 16 to No. 23, both the rate of change of the resistance value and the rate of change of the B constant at 25 ° C are significantly smaller than those of the SMT thermistor according to the present invention, and are extremely stable.

 In particular, in the SMT thermistors having compositions No. l to No. 10, Co is the main metal as the second phase crystal phase with the cubic spinel-type crystal phase as the structure of the sintered crystal phase. N a C 1-type cubic crystal phase as the component, cubic phase with Cu as the main metal component, and / or monoclinic crystal phase with Cu as the main metal component or the second phase of each By containing at least two types of crystal phases, the resistance value and the B-constant change rate within approximately 1% were achieved, and the reliability of high-temperature storage was significantly improved. In addition, in addition to the SMT semiconductors having compositions No. 1 to No. 10, NaC 1 type cubic crystal containing Co as the main metal component as the second phase crystal phase in the cubic spinel type crystal phase, A composition containing at least one of the cubic phase containing Cu as the main metal component and the monoclinic crystal phase containing Cu as the main metal component, or at least two of the respective second phase crystal phases. Similar results could be obtained when using the one having the above. This is thought to be because the crystallinity of the grain boundaries of the cubic spinel-type crystal phase is improved by precipitating the second phase having the above-described structure.

 On the other hand, the SMT thermistors of No. 11 to No. 12 are composed of a single phase of a cubic spinel-type crystal structure. % As good as%, it has achieved zero reliability.

 From the comparison of No. 13 to No. 15, the effect of the addition of Ti becomes apparent. C That is, the composition of a sintered body composed of Mn, Co, and Cu as metal components (N By adding 6 mol% (N o. 14) and 10 mol% (o. 15) of Ti to o. 13), respectively, the resistivity was significantly increased while keeping the B constant almost constant. It turns out that it gets.

 From the above results, it became clear that the sintered body for thermistor according to the present invention was extremely suitable for effectively producing and managing products having various thermistor characteristics.

 On the other hand, the target resistance value yield, which is one of the criteria for determining mass productivity, is ± 3%, and the thermistor sintering time according to the present invention is independent of the crystal phase of the sintered body.

One At about 100%, and at 1% of soil, the strength is as shown in Table 1 above and is as shown in Table 2 below. Table 2

 Thus, the cubic spinel single phase is higher than 9 °%, and the pedestal containing the cubic spinel phase and at least one second phase is higher than 7 °% and lower than 80%, which is extremely good. Met.

 Even though the contents of Cu and Ti are within the range of 1 to 24 mol% as in No. 22 to No. 23, the mol% of the Co metal component is 46- If the value is out of 65, the high-temperature storage reliability (resistance change rate, B-constant change rate) will decrease even if the target resistance value yield is high.

 FIG. 3 shows a desirable composition area (gray area) of the constituent metal component mol% of the sintered body for a thermistor of the present invention in order to improve the accuracy of the thermistor product and improve the yield and the reliability at high temperature storage. With this composition range, a highly reliable thermistor can be obtained.

 Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings. First, the manufacturing process of the thermistor sintered body will be described with reference to the flowchart shown in FIG.

First, commercially available manganese oxide, cobalt oxide, copper oxide, and titanium oxide were weighed to obtain the compositions shown in Table 1, mixed on a ball mill for 24 hours, and dehydrated and dried (step 1). Next, the dried powder was calcined at 850 to 950 ° C under atmospheric pressure for 2 hours, and the calcined powder was again ground for 24 hours by a ball mill, and then dehydrated and dried to obtain a raw material powder (step 2). .

 A binder was added to the raw material powder thus obtained, mixed, and then dried again (step 3).

 Finally, the raw material powder is formed into a pellet having a diameter of 5 mm and a thickness of lmm, and the obtained pellet is heated at a temperature of 1,000 to 1300 ° C for 1 to 4 hours. Firing was performed (Step 4).

 A disk-type thermistor was formed using the pellets of the thus obtained sintered body of thermistor as shown in FIG.

 That is, an Ag-based paste was applied to the upper and lower surfaces of the pellet 1 (Fig. 2 (a)) (Fig. 2 (b)), heated at 200 ° C for 5 minutes, pre-dried, and further heated at 70 CTC. Firing for 10 minutes forms the electrode 2 (Fig. 2 (c)).

The specific resistance of the disk-type thermistor obtained in this way was calculated from the R ₂₅ measured at 25 ° C and the geometric shape, and the B constant was calculated from the resistances at 25 ° C and 50 ° C. Calculated.

For comparison, the composition ratio of Mn, Co, Ti, and Cu was varied in the pellet formation process shown in Fig. 1, the resistance was measured for each, and the specific resistance and the Β constant were calculated. The results are shown in Table 3. In the table, the target resistance value after sintering ± 1% yield is a conventional example (No. 115, 116) and a comparative example in the present invention (No. 112 to 114, 117, 118) Compared with that, the yield of the sintered body of the thermistor according to the present invention is remarkably high, and has a great effect on the improvement of the yield of the product and the improvement of the reliability of high temperature storage at 100 ° C or lower in addition to the improvement of the accuracy. Table 3 Composition ratio of metal components (% by weight) Specific resistance B constant

 N o M n C 0 C u Ti (K) A R / R (R) Yield (¾)

^P 25

 0 1 38 0 51.1 4.9 6.50 450.8 3700 0.66 76

0 2 38. 3 51.5 4.9 5.3 374.9 9 3670 0.8 78

0 3 35 3 47.5 5 9 11.3 3279 3800 1.5 95

0 4 36 5 49.1 6.1 8.3 869 3690 1.292

0 5 38 1 51.3 6 44.2 212 3580 0.673

0 6 34 8 46.8 8 6 9.8 598 3570 1.3 94

0 7 35 9 48.3 8 8 7.0 221 3480 1.0 92

0 8 37 0 49.8 9 1 4. 2 116 3440 0.472

0 9 34 4 46.3 11.0 8.3 199 3490 1.3 95

1 0 35 9 48. 4 11 5 4. 2 86 3340 1.0 90

1 1 28.6 38.6 4 8 28.0 2700 3830 2.091

1 2 24.9 34.1 6 0 35 3000 3860 3 55

1 3 41.6 21.1 21.5 15.8 58 2800 2.853

1 4 45 3 22.9 23 5 8.3 48.2 2810 2.7 50

1 5 45.0 49.6 0 4 Ni 5.0 200 3500 0.8.40

1 6 45. 0 49. 2 0.8 Ni 5.0.0 400 3700 0.840

1 7 22. 0 40.0 5.0 0 33.0 2900 3900 3.05 55

1 8 20. 0 42. 0 4. 0 34. 0 3100 4000 3.00 50

In Table 3, the high-temperature storage test was performed at 90 ° C for 1000 hours, and the resistance change at 25 ° C before and after the test was measured. Here, sample No. 101, 102, 105 has a structure consisting of a NaC1-type cubic phase with a cubic spinel-type crystal phase as the main component and a second phase with Co as the main metal component. As in the case of Example 3, both the high-temperature storage reliability and the target resistance value yield (± 1%) were sufficient for mass production, and showed good results. Sample No. 1◦8 mainly consists of a cubic spinel-type crystal phase, and as the second phase, a Na C 1-type cubic phase with Co as the main metal component, and a cubic phase with Cu as the main metal component. It has a structure including a crystal phase, and showed good results as described above. No. 103, No. 104, No. 106, No. 107, No. 10, No. 110, No. 111 are single-phase cubic spinel-type crystal phases. However, the target resistance yield (± 1%) is high, and the reliability of high temperature storage at 9 CTC slightly decreases.

 Samples Nos. 112 to 118 show the results of a disk thermistor deviating from the composition range of the present invention. Composition with the sum of Cu and Ti contents exceeding 4% by weight in% by weight, and Mn or even in the range of 1 to 40% by weight of the total of Cu and Ti contents in% by weight. When the content of Co deviates from 24 to 50 and 36 to 60, respectively, the target resistance value ± 1% yield is remarkably reduced, and the high-temperature storage reliability is also reduced.

 In No. 113 and No. 114, the target resistance yield was high because the cubic spinel-type crystal phase was particularly unstable in the heat treatment process including the firing step, and was transformed into the tetragonal spinel-type crystal phase. It seems to have declined.

FIG. 6 shows a desirable metal component weight% composition range (gray portion) of the thermistor sintered body of the present invention for improving the characteristic value yield and increasing the integration of the product. In this composition range, the target value characteristic yield is high, the high-temperature rule-of-law reliability of 100% or less can be secured, and thermistors can be obtained with high mass productivity.

 This sintered ceramic body is a laminated ceramic body in which electrodes are interposed between a disk-shaped ceramic body, a chip-shaped thermistor body, a surface-mounted chip thermistor, and a thermistor sintered body. It can be applied to miss evenings. Industrial applicability

-11- As described above, according to the present invention, the crystal structure is stable, the variation in the electrical characteristics among the elements can be suppressed, and the environmental resistance, especially the characteristics and stability at high temperatures, can be improved. Because it is excellent, it is extremely effective as a material for thermistors for various temperature sensors or for temperature compensation for circuits that require high accuracy and high reliability.

Claims

The scope of the claims (1) In a thermistor oxide semiconductor having a negative resistance temperature characteristic, the main constituent metal is composed of Mn and Co, and Cu and Ti are further expressed as 0.1% by mol% total of the metal component. A sintered body of a thermistor characterized by containing up to 24%. (2) The content of the metal main components Mn and Co constituting the thermistor sintered body is 30 ≤ Mn ≤ 52 and 46 ≤ Co o ≤ 65, respectively, in mol% with respect to the metal component. The sintered body of thermistor according to 1.  (3) In the thermistor sintered body, the contents of Cu and Ti simultaneously added to Mn and Co, which are the main metal components, are each represented by mol% with respect to the metal components.  0.04 ≤ Cu u ≤ 14, 0.0.06 ≤ T i ≤ 10 3. The sintered body of a thermistor according to claim 1 or 2, wherein (4) In the thermistor sintered body in which the main metal component is composed of Mn and Co and Cu and Ti are added, the sintered body is mainly composed of a cubic spinel-type crystal phase, and The second phase is composed of a NaC1-type cubic crystal phase mainly composed of Co, a cubic crystal phase mainly composed of Cu, and a monoclinic crystal phase mainly composed of Cu. The thermistor sintered body according to any one of claims 1 to 3, wherein the sintered body contains at least two of any one or each of the second crystal phases. (5) A thermistor sintered body characterized by containing Mn and Co as main components as metal components and containing 0.1 to 40% by weight in total of Cu and Ti.  (6) Claim 5 is characterized in that the contents of the metal components Mn and Co are 24≤Mn≤50 and 36≤Co≤60, respectively, in terms of% by weight with respect to the metal component. Thermistor sintered body.  (7) A thermistor sintered body made of an oxide semiconductor for a thermistor having a negative resistance temperature characteristic is formed into a disk shape or a chip shape to form a thermistor body, and at least one pair of the thermistor body is formed. In a thermistor device with electrodes formed at both edges, The main component metal of the thermistor sintering is composed of Mn and Co, and further contains 0.1 to 24% of Cu and Ti in total mol% of the metal component. It is a mistake.  (8) The content of the metal main components Mn and Co constituting the thermistor sintered body is strong, and the mole percent of the metal component is 3◦≤Mn≤52, 46≤Co≤65. The thermistor device according to claim 7, wherein  (9) In the thermistor sintered body, the content of Cu and Ti simultaneously added to Mn and Co, which are the main metal components, is in mol% with respect to the metal component.  0.04 ≤ C u ≤ 14, 0.0. 06 ≤ T i ≤ 1 0 9. The thermistor device according to claim 7, wherein:  (10) In the thermistor sintered body described above, wherein the main metal component is composed of Mn and Co and Cu and Ti are added, the sintered body is mainly composed of a cubic spinel-type crystal phase, and Either a Na C 1-type cubic crystal phase mainly composed of Co, a cubic crystal phase mainly composed of Cu, or a monoclinic crystal phase mainly composed of Cu as the second phase The thermistor device according to any one of claims 7 to 9, wherein the thermistor device contains at least one or each of the second phase crystal phases. (11) A thermistor sintered body made of an oxide semiconductor for a thermistor having a negative resistance temperature characteristic is formed into a disk shape or a chip shape to form a thermistor body, and at least one of the thermistor body is formed. In a thermistor device with electrodes formed at both ends of the pair,  A thermistor device comprising Mn and Co as main components of the thermistor sintered body and containing Cu and Ti in a total amount of 1 to 40% by weight.  (12) The content of the metal components Mn and Co is 24≤Mn≤50 and 36≤Co≤60, respectively, in terms of% by weight with respect to the metal component, as described in claim 11. Thermistor device.