JPS62235267A - Ceramics electric joining method - 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 [Field of Industrial Application] The present invention relates to a method for electrically bonding ceramics using electrical energy.

[Prior Art] For example, when non-conductive ceramics are to be joined, the applicant places an adhesive that is conductive at high temperature on the joint surface of the non-conductive ceramic and heats the joint surface. At the same time, we proposed an electrical bonding method for ceramics that applies a high DC or AC voltage to both ends of the bonding surface.

FIG. 2 is an electrical connection diagram of a device for carrying out a conventional electrical bonding method for ceramics, in which a commercial AC power source 1 short-circuits the secondary winding 2b of a welding transformer 2, which has a drooping characteristic, for example. is connected to the primary winding 3a of the step-up transformer 3 via this primary winding 2a, and is connected to the secondary winding 3b of the step-up transformer 3.
Discharge electrodes 4a and 4b are connected to both ends of the welding transformer 2, and a high voltage can be applied between them, and by changing the reactor of the welding transformer 2, an arbitrary N current can be applied. Next, the adhesive 5, which is conductive at high temperatures, is interposed between the bonding surfaces of the non-conductive ceramics 5a, 5b, and the spouts and discharge electrodes 4a, 4b of the snowstorms 7a, 7b are attached to the bonding surfaces of the non-conductive ceramics 5a, 5b. The discharging electrodes 4a and 4b are arranged so that the gaps between the tips of the discharge electrodes 4a and 4b and the bonding surfaces are approximately 2 mm.

Now, the snowstorm 7 placed on both sides of ceramics 5a and 5b
a, 7. Heat the joint surface to 850℃ with combustible gas flame from b.
While heating to 900°C, a discharge voltage of 1000 to 10000 is applied between ff14a and ff4b depending on the bonding width of the ceramics.
When an AC voltage of V is applied, the adhesive 5
As the conductivity of the electrodes improves, arc discharge occurs between the discharge electrodes 4a and 4b and both ends of the bonding surface, and a distance of several tens of meters is generated.
A current of approximately A or more is applied to the adhesive 5. For example, in ceramics with a bond width of 17 mm, when a voltage of 6000 V is applied, a current of about 0.5 A flows. As a result, the adhesive 5 is heated to a high temperature by Joule heat, melts in a short time, and firmly joins the ceramics 5a and 5b.

If the area of the joint is large, the entire surface may be joined while moving the ceramic or snowflake using an appropriate moving means (not shown). Further, by providing multiple pairs of snowstorms, a wide area can be bonded simultaneously.

Here, adhesives that have conductivity at high temperatures include:
Kaolin, A +2203. The main component is a glass component such as S i 02, and oxides, sulfides, chlorides, etc. of copper, nickel, manganese, indium, molybdenum, zinc, etc.
Oxides of rare earth elements such as lanthanum, indium, vanadium, holmium, and yttrium, metals such as molybdenum, manganese, tungsten, iron, copper, silver, nickel, tin, and zinc, fluorides such as calcium fluoride, sodium fluoride, etc. Examples of known adhesives include appropriately blended adhesives. Further, as the combustible gas, combustible gases such as city gas, propane gas, hydrogen/oxygen gas, etc. may be used alone or in combination as appropriate.

In addition, when applying a DC voltage, 2 of the step-up transformer 3
A rectifier circuit may be added between the secondary winding 3b and the discharge electrodes 4a, 4b.

[Problems to be Solved by the Invention] If the voltage applied to both ends of the bonding surfaces of the ceramics to be bonded through an adhesive that is conductive at high temperatures is a commercial frequency alternating current voltage, arc discharge may occur. There is a risk of failure to re-ignite the arc near the zero point of the current flowing in the adhesive, and in order to start the discharge, for example, a high voltage of 6000 V or more must be applied to ceramics with a bond width of 7 mm. Must be. Therefore, applying a high voltage is not preferable from the viewpoints of work, safety, and increase in input power. On the other hand, in the case of DC voltage, there is a risk that the airflow generated in the adhesive will change due to high temperature explosion of the adhesive, which may interrupt the discharge. Under the above-mentioned conditions, a high voltage of 5000 V or more will be applied, which is not preferable from the viewpoint of work, safety, and increase in input power.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a high-frequency voltage is superimposed on an AC voltage or a DC voltage as the voltage applied to both ends of the joining surfaces of the ceramics to be joined. It is characterized by what it did.

[Function] When the temperature of the adhesive described above is raised to 850°C to 900°C, the molecules are thermally ionized into electrons and positive ions.

In such a thermally ionized state, if a high voltage is applied to sufficiently move electrons and positive ions, the electrons and positive ions will be accelerated to 1/10 to 1/10
It is known that the amount of electrons and positive ions increases in a short period of seconds, and even if the voltage is lowered immediately thereafter, the amount of electrons and positive ions is sufficiently maintained. That is, once generated electrons and positive ions are prevented from recombining by a slight ionization effect, so that once generated arc discharge continues.

For example, when applying a commercial frequency AC voltage of 6000V, the recombination time is usually 1/103 to 1/105 seconds near the voltage zero point, and the voltage is higher than the above-mentioned AC voltage, for example, a high frequency voltage of 10000V. By superimposing , electrons and positive ions are prevented from recombining at least once, so that the electrons and positive ions are maintained at a certain value. After that, even if the potential is about 1000V, for example, electrons and positive ions are multiplied by this electric field, so the above-mentioned AC voltage can be reduced to 700 to 2000V. Further, even when the AC voltage is reduced in this way, the arc can be re-ignited reliably by superimposing the high-frequency voltage on the AC voltage near the zero point of the current flowing through the adhesive. On the other hand, a similar phenomenon can occur when applying a DC voltage, so by superimposing a high-frequency voltage at startup, the applied voltage can be reduced, and by continuously superimposing a high-frequency voltage, some When arc breakage occurs due to
Re-ignition is ensured.

[Example] The present invention will be described below with reference to the drawings. FIG. 1 is an electrical connection diagram of an apparatus for carrying out the method of electrically bonding ceramics according to the present invention, and the same components as in FIG. 2 are given the same reference numerals. In the figure, the commercial AC power supply 1 is
For example, the secondary winding 2b of the welding transformer 2 having drooping characteristics
is short-circuited and connected to the primary winding 3a of the step-up transformer 3 via this primary winding 2a, and a bypass capacitor 8 is connected to both ends of this secondary winding 3b. Furthermore, a high frequency generator @10 is connected to the primary winding 9a of the air core transformer 9 at one end, and is connected to the discharge electrode 4a via the secondary winding 9b. A discharge electrode 4b is connected. That is, the high frequency voltage generated from the high frequency generator 10 becomes a high voltage in the secondary winding 9b of the air core transformer 9, and this high frequency voltage is superimposed on the secondary output voltage of the step-up transformer 3. A voltage is applied between discharge electrodes 4a and 4b.

Next, after interposing an adhesive 5 that is conductive at high temperatures between the bonding surfaces of the non-conductive ceramics 5a and 5b,
Blizzard 7a, 7b nozzles and discharge electrodes 4a, 4
b are arranged toward both ends of the joint surface.

Now, the snowstorm 7 placed on both sides of ceramics 5a and 5b
a, 7. Heat the joint surface to 850℃ with combustible gas flame from b.
In the case of ceramics with a bonding width of 17 mm, for example, when heating to 900° C. and applying a voltage obtained by superimposing a high frequency voltage of 1 oooov to a commercial frequency AC voltage of about 1000 V to the discharge electrodes 8i4a and 4brm, the discharge N electrode 4a
, 4b and both ends of the joint surface. After that, adjust the reactor of the welding transformer 2, and
The adhesive 5 is energized with a current comparable to that when only an AC voltage of a commercial frequency of ooo v is applied. At this time, the current due to the high frequency voltage flows through the bypass capacitor 8. As a result, the adhesive 5 is heated to a high temperature and melted, and the ceramics 6a and 6b are firmly joined. Here, the timing for generating the high-frequency voltage may be continuous, but in the configuration described above, the phase of the energizing current is delayed by approximately 90 degrees with respect to the applied AC voltage, so the energizing current near the zero point of the applied voltage It is more effective if it is set near the zero point of .

In the above explanation, the type of applied voltage was commercial frequency AC voltage, but in the case of DC voltage, the
A rectifier circuit may be added between the next winding 3b and the bypass capacitor 8.

In addition, by partially forming the ejection ports of the snowstorms 7a, 7b into protruding shapes, the snowstorms 7a, 7b can be used as discharge electrodes.

[Effects of the Invention] As described above, according to the present invention, by superimposing a high-frequency voltage on the voltage applied to the adhesive, the applied voltage can be reduced compared to the conventional method, thereby reducing power equipment and This improves safety for the human body, improves workability, etc., and also ensures that the arc is re-ignited even when the applied voltage is reduced.

[Brief explanation of drawings]

FIG. 1 is an electrical connection diagram of an apparatus for implementing the ceramic electrical bonding method of the present invention, and FIG. 2 is an electrical connection diagram of an apparatus for implementing the conventional ceramic electrical bonding method. 1... AC power supply, 3... Step-up transformer. 4 a, 4 b...Discharge electrode, 5...
··glue. 5 a, 5 b... Ceramics to be joined. 7 a, 7 b...blizzard, 10...
・High frequency generator sub-agent

Claims (1)

[Claims] 1. Butt ceramics to be joined that are electrically conductive at high temperatures, or butt ceramics to be joined with an adhesive that is electrically conductive at high temperatures, heat both ends of the joining surfaces with a gas flame, and A method for electrically bonding ceramics in which a DC or AC voltage is applied to a portion of the ceramics, the method comprising applying a voltage obtained by superimposing a high-frequency voltage on the DC or AC voltage.