JPS59221986A - Ceramic heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a helical heater that facilitates and provides touch-resistant markings. Hiramic heaters, which use the conventional Reramic Zamister as a heating element, are made by uniformly applying metal to both end surfaces of the heating element using chemical plating, paste, or thermal spraying methods. d9, therefore, this j;
However, it has the advantage that the current density 1a of the heating element is uniform, and therefore the temperature distribution is uniform. The metal electrode is corroded due to the broken bond (1b)
The quality deteriorated, and there were problems with the use of the product.

Therefore, the present invention has been made to improve these conventional drawbacks, and has the highest corrosion resistance on both end faces of the heating element, and has a lower specific resistance than any other heating element. By uniformly forming a small electrode layer made of f-helamix and providing a ring-shaped metal electrode part on the periphery of each electrode layer, only the metal electrode part can be easily sealed 41? IJ report and 1liJ
It is an object of the present invention to provide a helical heater which has good properties (1) whose metal electrodes are free from corrosion even when used in an I atmosphere.

That is, the present invention provides a positive characteristic ceramic heating element layer that generates heat when energized, and a ceramic heating element layer provided on both end surfaces of the ceramic heating element layer, which has a normal temperature specific resistance of The present invention relates to a ceramic heater comprising: a ceramic electrode layer having a small specific resistance J at room temperature; and a ring-shaped metal electrode portion provided on the peripheral edge of the ceramic electrode layer.

Correctness 1 here! IL! The lamic heating element layer (hereinafter simply referred to as 1 photothermal element layer 1) is made of a metal oxide sintered material whose resistivity is j-W?J at the upper temperature limit. Typically, I14 is a Ba1-i03 semiconductor.
will be accomplished. (The specific resistance at room temperature +:1 can be controlled by slightly doping a specific substance.) Other positive characteristic ceramic heating elements include 7n.
, 7i, Ni oxide type, [1) Fe, Nl + oxide type S1 type, chalcogenite, etc. can be used. The reason why a positive temperature ceramic heating element is used as the heating element is to facilitate constant temperature control. Furthermore, ceramic electrode layers made of a ceramic material having a small specific resistance at room temperature are provided on both end faces of the heating element layer. Zuru no IJ
, Relamic Den 4! This is to uniformly distribute the current in the plane of i fW and to make the current density uniform in the plane perpendicular to the current in the heating element. Further, a ring-shaped metal electrode portion is provided at the peripheral edge of the ceramic electrode layer. A method such as a chemical plating method, a paste method, or a thermal spray method can be used to form the metal electrode portion. As the material, A-mic electrode metals such as aluminum, nickel, silver, and Ag+base metals can be used. In addition, a hoist using a 1-no-mister with positive characteristics as a helical electrode layer (J, forming a photothermal body 11° 1)
l j, sushi, diI-J specific resistance at room temperature is 1/1.5
It is desirable that the following is true, and in 1 noli Iij,
I want it to be 100 degrees higher than 30℃: 1. This [,tX
It is possible to form a dense current circuit on the plane of the ramic electrode layer by heating it.
)ru night 1? This is because the resistance of the ceramic electrode 14 layer remains smaller than the resistance of the heating element layer even in the case of crystallization, resulting in a 1116-like pattern. In short, from room temperature [1 target light heat]
In order to improve the quality, it is necessary that the specific resistance of the material of the ceramic electrode layer 44i is smaller than the specific resistance J of the material v11 constituting the heating element. YotsuC, registration rlrl layer (21, S t C1T 1C1N I O etc. 8
(74 can also be formed by f'+ 4''i 1!l Leemister.

The metal electrode trB is formed in a ring shape at the periphery of the ceramic electrode layer. Therefore, by shielding this ring-shaped metal electrode portion from the atmospheric debris of 1), corrosion of the electrode is prevented. Also ring-shaped (
Even if this metal electrode part is made of 4f4, the specific resistance of the ceramic electrode layer is expressed as -1-)Δ(, and the specific resistance of the heating element J,
Since the heating element layer has a small structure, a uniform current density distribution is achieved in the heat generating layer 4', II').

Hereinafter, the present invention will be explained in detail! I will explain based on the example.

FIG. 1 is a partially perspective view showing the 414 configuration of a heramic heater according to an embodiment of the present invention (4-target<7). 3. On the hour 11 II? The ramic photothermal layer 2 is made of ditaneous barium-based half-barium 414 (1) The heating element layer 2 is made of barium titanate containing 0.4 mol of Y203. % doping.Positive t!11=Both OJ: surfaces of the lamic heating element layer 2 have ceramic electrode layers 4a, 4
b is joined. This ceramic electrode layer (well, also made of a barium ditanate semiconductor) was prepared by doping barium butane with 0.2% 'l' 203.
ζ temperature chamber (1) 1, which has a resistivity smaller than that of the material of the photothermal layer 4a, 41+
Metal electrode portions 6a and 6b are provided in a J-ring shape on the periphery of the electrode. For the gold h13 electrode portions 6a and 6b, chemical metal 4-N1Δ-mic electrodes were used.

The wooden lamic heater was manufactured using the following steps.

(1) Add an organic binder and granulate it.1. :Fill things into gold 511.

(2) When filling, fill in three layers.

(('I) Press molding.

(4) Furnace 1 formation (firing in bonded state)'? l-ru.

(5) Fuririru the electric 4^.

Moreover, even if the molded parts of Sea I~ are laminated into three layers by C device 'l', J, I, 7 A heramic heater with such a structure +, t, , metal mold folded parts 6a and 6b. By applying a voltage between them, a current flows in a direction perpendicular to the heating element layer. This It'1. The specific resistance of the material that forms the helical electrode layer [well, 1. The material that makes up the ceramic heating element layer. (A-) (A current flows through the back surface -4, l; of the b1 ceramic electrode layer, and as a result of A, the helamic electrode layer /la is obtained. 41) < r current animal 1 α molecule l + as cow, uniform i nail heat generation 71 3, metal) ゛ IIN pole part (, 15
, because it is formed in a ring shape 414, the metal electrode part 6
J, S, l to Rirukonin who shields a, and (3b in a ring shape)
Figure 2 shows a modification of this embodiment.It can also be used in gas or liquid.

The embodiment of FIG. 1 and V+47: points (, 11,
There is a theory that there are many communicating holes 8 in one line in the axial direction of a, 411 (no,
It has a so-called honeycomb shape.

FIG. 3 shows the relationship between the area of the metal electrode portion and the resistance jν'L value between the metal electrode portions 4a and 4b of the ceramic heater according to this embodiment. In measuring this special 1!1-, the ceramic heater has a cross section of 7 cm that is heavy on the current t1. , 11h property is 0.1cmg12lamic electric power & h? j's J+/ is 0.1 On+, resistance of hourly 1-1-reramic heating element layer is 0.5Δ-1x, "P:+-Lee+:a 8o
℃, potato temperature 1 old resistance 350 cm, resistance of one end layer of ceramic electrode layer 171-- tx, 1-1-ri one point 130'
C,'A\low temperature specific resistance 7oΩcn+IJ.

(1 is actual measurement data C in which the resistance between the electrodes was measured with various changes in the area of the 1 gold bending + + i part in the heramic heater of this example. 1, part A) Illustration +
: i 11, This is the measured value when the metal part of 44i is made the same as the planar surface of the helical electrode layer (^^) and the electrode layer is formed uniformly. In addition, the broken line ■ in the figure The electrode part
J! of the interelectrode resistance value when both end faces of the heating element are configured uniformly and the end area of the ceramic plate is varied. 11 essays 1+i
It is. From this, the area of the metal electrode part is 2 to 7 cm.
When it is between m2, the surface of the ring-shaped metal ill ~ part (L
It can be seen that the resistance is almost uniform regardless of ll1
In other words, the area of the metal electrode part is 2 cm2, and it is formed into a ring shape. is d3 in the cross-sectional area perpendicular to the current V↑, and is -4y
It can be seen that it is flowing to A. .

That is, the current (3I) is not localized between both ring-shaped electrode parts.

Next, the results of measuring the heat generation characteristics of the ceramic heater of this example are shown in Fig. 5). This heat generation characteristic is illustrated in FIG. 4: J:U<r'L? In the ceramic heater, the F part-1-2 of the metal electrode part such as the central part T1 of the ceramic heater
The temperature was measured over time. In this ceramic heater (13), the metal electrode part has a ratio of 1/2 of the area of A to the area of the ceramic electrode layer.
No. 41 was completed in A91.

J, sea urchin, center T1 as seen from the experimental data shown in Figure 5
There is a difference in the rate of γ rise (temperature at the lower part of the metal electrode), and the metal? This indicates that the temperature increase rate is greater at the lower part of the Ui pole. Immediately from this, standing 1
It can be seen that in the rising time period ζ, the current is concentrated around the electrode portion. However, in the steady state after 5 seconds, both men are at the same position. In other words, 1fld degree of 22 parts of the ceramic with stepped metal electrode parts is on the back, and the resistance 1i+ of that part of the positive characteristic heating layer is
4 rises, and the current tries to flow uniformly toward the center, which causes the current density to become uniform in the cross section perpendicular to the current direction. fever is iI
It is thought that there is.

Next, we will discuss a four-layer structure of a ceramic heater in which the metal parts of the wood-ceramic heater are sealed.

Figure 6 is a cross-sectional view of a sealed ceramic heater with node 1 formation.
be. A metal tip (on the plate 24, a part of the same lamic as in the above-mentioned embodiment is disposed. Part 1: Metal electrode part 6
1) is in electrical contact with the metal substrate 24. metal L4
1A 2 /I is provided with a tf426 in a circumferential manner, and an O-ring 16b is provided on this side.The ceramic heater of this embodiment also has a window in the center. Part 1
/14! - A disc-shaped convex fixing member 12 and a metal substrate 2
4. On the inner surface of the fixing part hand A12, there is a ring-shaped ring along the periphery of the disc-shaped window part 14.
8, and an O-ring 16a is disposed within the ring 28 to hermetically seal and protect the metal electrode portion 6a from corrosive atmospheric gas. A fixing member 12 G; U having a circular convex shape is fitted with a bolt 18 and fixed to a -U1 screw provided on the metal substrate 24. Due to the action of the O-rings 1611 and 168 and the pressing force, the metal electrode parts 6a and 6b are hermetically sealed from corrosive atmospheric gases and are prevented from corrosion. Further, the two metal electrode portions 6a are taken out to the outside through a rubber bushing 30 to the lead wire 20 in an airtight manner.

FIG. 7 is a block diagram of an apparatus in which a lamic heater is applied to heat a corrosive gas or liquid that is flowing. The piping member /'IO that guides the corrosive gas has a flange portion, and the piping members 'IOa and /IOb are joined. A ceramic heater having a honeycomb-shaped communication hole shown in FIG. 2 is disposed in the flange portion perpendicularly to the gas flow path.

It is the function of the O-rings 42a and 421) that hermetically seals the metal electrode portion from corrosive gases. That is, the ceramic heater connects the piping members 408 and 40 through the O-ring.
1), and the metal electrode parts (3a, 6b) are hermetically sealed.The metal electrode part is a ring-shaped spring bullet t11 disposed concentrically with the inner diameter of the gas flow path of the piping member. /I (5a, /I 611 is pressed by J. The pressing force is the concentric ring-shaped insulating plate 47
It is supported by Ia and /I411. The metal electrode parts 6a and 5b are made of rubber bumpers 50 aN b O
The lead wires 48a, 4 are sealed airtight by b.
It is electrically connected to the outside via 8b (1).

In summary, the present invention has advantages (1) and (4) disadvantages that generate heat when energized.
L-Is it something that is made up of both end faces of the lamic heating element layer?
TJ: A ceramic heater C with a ring-shaped electrode is provided at the periphery of a flat ceramic electrode layer.

Therefore, according to the ceramic heater of the present invention, since the metal electrode portion is formed in a ring shape only at the peripheral portion, it is possible to configure the metal electrode portion in a closed type. Since it is OL that can be brought into contact with corrosive gases or liquids, corrosion of all 1-electrode parts can be prevented. Furthermore, since the ceramic electrode layer is made of a material with a lower resistivity than the heat generating layer 11, the current density can be made uniform, and a uniform 4+- heat generation effect can be generated.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view of a ceramic heater according to an integral embodiment of the present invention. FIG. 2 is a sectional view of a lamic heater according to a modification of the same embodiment. FIG. 3 is a graph showing the variation characteristics of the inter-electrode resistance with respect to the area of the metal electrode portion in the lamic heater of the same example. FIG. 4 is a measurement explanatory diagram for measuring the heat generation characteristics of the ceramic heater of this example, and FIG. 5 shows the measurement data of the heat generation property 1/1. Figure 6 is a cross-sectional view of a ceramic heater in which the gold uJX electrode part of the ceramic heater according to this embodiment is constructed in an airtight shape. It is a configuration cross-sectional view of a Hiramic heater according to an example. 2... Hiramic heating element layer 4, a, 4b... Ceramic electrode layer 6a, (3b... Metal electrode part Special r1 Applicant Nippon Denso Co., Ltd. Company agent Patent attorney Hirotoshi Okawa Patent attorney Shudo Fujitani Patent attorney Akio Maruyama Go to Figure 1 32 Figure 3 Figure 4:, J, Figure 5:, % 6.1'1 1 No. 714

Claims (1)

[Scope of Claims] (1) A positive characteristic ceramic heating element 1frt which generates heat when energized; 4 grooves are formed on both end surfaces of the 1st characteristic 1st 1st helical heating element layer;
Its palm thirst IL resistance is 1t (18J,
(2) The ceramic electrode is composed of a ceramic electrode layer, a metal electrode part in the shape of an I-shaped piece provided on the peripheral edge of the ceramic electrode layer. (2) The ceramic electrode Things that make up the layers T1t, L,
Compared to the material constituting the heating element layer, the heating point is higher than -(30'C or more) and the specific resistance is 1./1.5C or higher. i[1ji
4Ilt? Qh characterized by consisting of humicus
Fi'1 A ceramic heater according to claim 1. (33) The material constituting the ceramic electrode layer is made of a negative characteristic ceramic whose resistivity at room temperature is d3 1/1.5 or more compared to the material constituting the heating element layer. Characteristic Features: The Hiramic heater according to Item 1. (/I) The ceramic heater according to claim 1, wherein a center portion of the heating element layer and the ceramic electrode layer has a large number of communicating holes.