Electric heating – Metal heating – For bonding with pressure
Patent
1992-06-03
1994-03-15
Evans, Geoffrey S.
Electric heating
Metal heating
For bonding with pressure
219118, 219601, 219611, C04B 3700, C04B 3702
Patent
active
052947696
DESCRIPTION:
BRIEF SUMMARY
FIELD OF APPLICATION IN INDUSTRY
The present invention generally relates to an electric joining method and more particularly, to a method for electrically joining a body to be jointed including a butted portion at least between electroconductive ceramics to be jointed or between an electroconductive ceramics to be jointed and a metal while relieving the thermal stress generated at the ceramics to be jointed.
BACKGROUND OF THE INVENTION
Conventionally, in order to join an electroconductive ceramics with an electroconductive ceramics or a metal, a method by a direct resistance heating, a method by a high frequency inductive heating, or a combination of these methods etc. have been proposed. According to the aforementioned method by a direct resistance heating, when an body to be jointed which is composed of two materials to be jointed parts at either side of a butted portion is arranged in contact with an electrode and supplied an electric current, a Joule heat is generated at the butted portion thereby to partially heat the butted portion. Therefore, a joining agent at the butted portion is melted, whereby the to be jointed parts are jointed together. According to the method by a high frequency inductive heating, an induction coil is provided around the butted portion of the body to be jointed, and the butted portion is partially heated by Joule heat resulting from the induction heating, so that the joining agent of the butted portion is melted. Meanwhile, when the method by a direct resistance heating is used in combination with the method by a high frequency inductive heating, a ceramics of a higher resistance, namely, having a lower electrical conductivity is heated beforehand by the high frequency inductive heating to lower the resistance value (that is, to increase the conductivity). Thereafter, the direct resistance heating is carried out to flow a large amount of current to quickly heat the butted plane.
FIG. 11(A) shows the structure when the conventional method by a direct resistance heating is performed. In the structure of FIG. 11(A), conductive cylindrical ceramics 1a', 1b' to be jointed are brought to butt against each other via a joining agent 3', thereby constituting a butted portion. Ring-shaped electrodes 2a', 2b' are provided butting against the corresponding ceramics 1a', 1b' in a manner as indicated in the drawing. Thermal insulators 4a', 4b' are placed at the end parts of the ceramics 1a', 1b', respectively. A voltage is impressed between the electrodes 2a' and 2b' while the ceramics 1a', 1b' are pressured by a pressuring device (not shown) via the thermal insulators 4a', 4b'. As a result, Joule heat is generated at the ceramics 1a', 1b' because of the flow of a current in a vertical direction to the butted plane of the ceramics 1a', 1b'. Since the butted plane is partially heated by this Joule heat, the joining agent 3' is melted, thereby joining the ceramics 1a', 1b' together. In such a case as above where the materials to be jointed are made of the same material in the same shape and jointed with use of electrodes of a small heat capacity, since the resistance values of both materials are equal to each other, the quantities of heat generated at materials to be jointed between the electrodes 2a', 2b' become equal to each other. Accordingly, the two materials to be jointed in the vicinity of the butted portion are heated generally uniformly as is indicated by a curve (a) of FIG. 11(B) and moreover no large temperature gradient is formed to the materials to be jointed in the vicinity of the electrodes. In employing the other two joining methods described earlier, if the materials to be jointed are in the same shape and of the same material, or if the joining temperature is low, there is no particular problem to be solved.
In the meantime, the electrodes 2a', 2b' for the direct resistance heating are generally formed of heat-resisting metal such as tungsten, molybdenum or the like or inorganic material with heat-resistance such as carbon or the like. These kinds of material have a go
REFERENCES:
patent: 4093839 (1978-06-01), Moliterno et al.
patent: 4717801 (1988-01-01), Brolin et al.
Hoshino Hisakiyo
Miyake Natsumi
Nishi Tokumitsu
Numano Masashi
Okuda Kouji
Daihen Corporation
Evans Geoffrey S.
LandOfFree
Electric joining method of material including ceramics does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric joining method of material including ceramics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric joining method of material including ceramics will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1537313