JPH02152203A - Thermal resistor - Google Patents

Abstract

PURPOSE:To prevent a bonding strength between an electrode and an element unit from being lowered by a method wherein at least one kind out of composition raw materials for the element unit is contained in the electrode at a specific range in total. CONSTITUTION:A thermistor 10 contains a thermistor element 12 formed by sintering a metal oxide of Mn, Ni, Co, Al and the like so as to be sheetlike; electrodes 14 are formed on both faces of the thermistor element 12. The electrodes 14 are formed by baking an electrode paste containing a total of 0.1 to 30wt.% of a metal oxide of Mn-Ni, Mn, Ni or the like composing the thermistor element 12 in addition to a metal powder of, e.g., Pt, Ag, Ag-Pg or the like. After a conductive paint 18 has been dried, it is baked and a glass film 20 is formed at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a temperature resistance element, and particularly to a temperature resistance element such as a thermistor used for temperature measurement or temperature compensation.

[Prior art]

An example of this type of thermistor is, for example,
It is disclosed in Japanese Patent No. 535.

As shown in FIG. 2, the conventional thermistor 1 has Mn, N
Electrodes 3 made of Ag, Ag-Pd, etc. are formed on both sides of the thermistor element 2, which is made by sintering metal oxides such as i, Co, etc. After adhering with conductive paint 5 and drying, 700 to 900
It was formed by simultaneously performing baking and glass coating 6 at a temperature of °C.

[Problem to be solved by the invention]

In the conventional thermistor 1, the adhesive strength between the thermistor element 2 and the electrode 3 was weak. In particular, when the metal lead wire 4 is bonded to the electrode 3 with the heat-resistant conductive paint 5, the heat-resistant conductive paint 5 shrinks due to sintering, which weakens the adhesive strength between the thermistor element 2 and the electrode 3, resulting in poor bonding. This causes poor aging characteristics and processing changes.

Therefore, the main object of the present invention is to provide a temperature resistance element that does not weaken the adhesive strength between the element unit and the electrode.

[Means for Solving the Problems] Simply put, the present invention provides a temperature resistance element including an element unit formed with a predetermined composition and electrodes formed on both sides of the element unit. At least one of the composition raw materials is contained in a total of 0. 1-30
It is a temperature resistance element characterized by containing wt%.

[Effect]

Depending on the composition raw materials of the element unit contained in the electrode, for example, the shrinkage of the electrode during integral firing is similar to that of the element unit, so only the electrode is thick (reduction in adhesive strength between the element unit and the element unit caused by shrinkage). Therefore, there is no need to peel off the electrodes when cutting out each element unit or connecting lead wires.

〔Effect of the invention〕

According to this invention, there is no decrease in the adhesive strength between the electrode and the element unit, so there is no problem of poor bonding, which has been a problem in the past.
No aging characteristic defects or processing change defects are eliminated.
As a result, not only can the rate of non-defective products during manufacturing be expected to improve, but also quality deterioration due to aging can be prevented.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

L Example] Referring to FIG. 1, the thermistor 10 of this example is M
The thermistor element 12 includes a thermistor element 12 formed by sintering metal oxides such as n, Ni, Co, and A1 into a plate shape, and electrodes 14 are formed on both sides of the thermistor element 12. This electrode 14 is an electrode containing a total of 0.1 to 30 wt% of a metal oxide such as Mn-Ni, Mn or Ni, which constitutes the thermistor element 12, in addition to metal powder such as PL, Ag, or Ag-Pg. It is formed by firing a paste. Each electrode 14 has a lead wire 16 made of a metal such as Dumet, and a heat-resistant conductive paint 1 such as Au or the like.
8. After drying the conductive paint 18,
The baking and glass coating 2o are carried out simultaneously at a temperature of 700-900'C.

The thermistor 1o obtained in this manner is manufactured, for example, by the following method.

First, a raw ceramic sheet to become the thermistor element I2 is prepared. That is, Mn, Ni.

Co and AI! , etc. are blended in a predetermined ratio and wet-mixed using a ball mill or the like. Thereafter, it is dehydrated and dried, and then calcined at 850'C for about 2 hours. After wet grinding, it is evaporated and dried, and an organic binder is added thereto to form a slurry.

The ceramic slurry thus obtained is applied by a doctor blade method to form a green ceramic sheet with a thickness of 200 μm. For example, 2 ceramic raw sheets
The sheet is cut into a size of 7×36fflI, and three of the cut sheets are stacked and thermocompressed to obtain a green ceramic sheet with a thickness of about 500 μm.

Next, an electrode paste to become the electrode 14 is prepared.

This electrode paste is made by adding a total of 0.1 to 30 wt% of at least one of the raw materials for the thermistor element 12, such as an oxide powder such as Mn-Nt, Mn or Ni, to a metal powder such as Pt. It is.

Then, this electrode paste is applied to both sides of a ceramic raw sheet having a thickness of 500 μm, and fired at 1200 to 1300° C. for about 2 hours. The fired ceramic sheet is cut into 0.51 TII11 squares, and electrodes 1 are placed on both sides.
A thermistor element 12 in which 4 is formed is obtained.

Further, lead wires 16 such as Dumet are bonded onto the electrodes 14 on both sides of the thermistor element 12 with a heat-resistant conductive paint 18, dried, and then baked at a temperature of 700 to 900°C.

Finally, although not shown, the thermistor element 12 is placed in a glass cap with the lead wire 16 fixed to the electrode 14, and the entire glass cap is heated by a carbon heater. Then, the glass cap is softened and the ends of the glass cap are sealed, and a radial type thermistor 10 sealed with a glass coating 20 is obtained as shown in FIG.

In the thermistor lO formed in this way,
When cutting the ceramic sheet after firing, or when cutting the lead wire 1.
Even when connecting the electrode 6 to the electrode 14, the electrode 14 did not peel off.

In the experiment, the thermistor elements were formed from Mn and Ni metal oxides, and the thermistors were manufactured using the above method by varying the type and amount of metal oxide added to the electrode paste. Initial resistance (R
) and its variation (δ) were observed. The result is
Shown in the attached table.

Sample numbers 2-4, 7-9 and 12 in Attached Table 1
Tests No. 1 to 14 are within the scope of the present invention, and no peeling of the electrode occurred either when cutting the ceramic sheet or when connecting the lead wires. In addition, the initial resistance (R
) and its variation (δ) did not cause any particular problems.

In addition, sample numbers 1, 6.11 and 16 are outside the scope of this invention, and since the amount of metal oxide added in these is too small at 0.05 wt%, all of them are difficult to remove when cutting or connecting lead wires. Sometimes the electrodes peeled off.

And sample number 5, which is also outside the scope of this invention.
, 10 and 15, electrode peeling did not occur, but because the amount of metal oxide added was too large (31 wt%), the electrode peeling problem did not occur, but the electrode density became too coarse and the initial resistance The value (R) and its dispersion (δ) are large.

In addition, although the above-mentioned Example demonstrated the radial type thermistor 10, it is not limited to this, and of course can also be applied to an axial type thermistor or a laminated thermistor.

Further, in the above-described embodiment, a case was described in which no glass frit was added to the electrode paste to become the electrode 14, but it goes without saying that glass frit may be added.

Furthermore, the present invention is not limited to thermistors, but is equally applicable to positive temperature coefficient thermistors and other resistance-temperature elements.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is an illustrative cross-sectional view showing the prior art. In the figure, 10 is a thermistor, 12 is a thermistor element, and 14 is an electrode. Table * Out-of-scope patent applicant Murata Manufacturing Co., Ltd. Agent Patent attorney Yama 1) Yoshihito Figure S

Claims (1)

[Scope of Claims] 1. A temperature resistance element including an element unit formed with a predetermined composition and electrodes formed on both sides of the element unit, wherein the electrode contains at least one of the raw materials for the composition of the element unit. A temperature resistance element characterized by containing 0.1 to 30 wt% in total. 2 A total of 0 of at least one of the composition raw materials of the ceramic raw sheet is added to the ceramic raw sheet having a predetermined composition.
．． 2. The temperature resistance element according to claim 1, wherein the temperature resistance element is formed by applying an electrode paste containing 1 to 30 wt% and then integrally firing it.