JP2002294305A - Electric-heating-type hip equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new electric-heating-type HIP equipment by which uniform sintered compacts can be rapidly obtained by making use of the characteristics of both of the electric-heating sintering method capable of rapid sintering and the HIP method capable of production of uniform sintered compacts. SOLUTION: The equipment has a high-pressure cylinder 10 containing conductive liquid 14. The high-pressure cylinder 10 has: a lower lid 12 for energizing the liquid 14 from an electric power source 17; a punch 13; and a means of applying external pressure to the liquid 14 from uniaxial direction via the punch 13. Sintering is performed by means of Joule heat of the liquid 14 while isostatically pressurizing a sintering material 16 held in the liquid 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric sintering apparatus for heating and sintering a powder while applying pressure, and more particularly to a novel electric sintering apparatus in which electric sintering and HIP are combined. .

[0002]

2. Description of the Related Art An electric current sintering apparatus is known as an apparatus for sintering powder by electric heating. As shown in FIG. 2, a conventional electric current sintering apparatus has a sintering mold 2 having a columnar space.
1 and a movable upper punch 23a and a lower punch 23 which are made of a conductive material from above and below.
Pressure is applied in one axis direction by b. In this pressurized state, the power supply 24 is passed through the upper punch 23a and the lower punch 23b.
After that, Joule heat is generated by conducting electricity and sintering is performed. As the power supply 24, a pulse power supply or a DC power supply is used.

[0003] This type of electric sintering apparatus is capable of rapid sintering due to an internal heating system utilizing electric power to the powder 22 itself and utilizing Joule heat. However, it was difficult to obtain a uniform sintered body due to the friction between the sintering mold 21 and the powder 22 and the friction between the powders because of the uniaxial pressing method. In particular, as the shape of the sintered body becomes more complicated, the disadvantage becomes more prominent.

[0004]

On the other hand, as a sintering apparatus for solving the above-mentioned problems caused by friction, a HIP (hot isostatic processing) apparatus as shown in FIG. 3 is known. This HIP device has a high-pressure cylinder 30 whose bottom is closed by a lower lid 31 and whose upper part is closed by an openable and closable upper lid 32. Upper lid 32
Is provided with a gas inlet 32-1 for introducing a pressurized inert gas into the high-pressure cylinder 30. High pressure cylinder 3
A heater 33 is disposed in the inside of the cylinder 0, and a heat insulating layer 34 can be interposed between the heater 33 and the inner wall of the high-pressure cylinder 30. The sintered powder material is placed on a support 35 in a high-pressure cylinder 30 in a state packed in a capsule. According to this HIP device, the above-mentioned problem of friction is solved, and a uniform sintered body can be obtained.

However, the sintered powder material packed in a capsule is placed in a pressurized inert gas, and the heater 3
3 sintering by external heating, there is a difference between the internal temperature and the external temperature of the sintered powder material, and it is difficult to sinter rapidly.

Accordingly, an object of the present invention is to provide a novel uniform sintered body which can be rapidly obtained by utilizing the features of both the electric sintering method capable of rapid sintering and the HIP method capable of obtaining a uniform sintered body. Another object of the present invention is to provide a simple energizing HIP device.

[0007]

According to the present invention, an energizing HI according to the present invention is provided.
The P device has a high-pressure cylinder containing a conductive liquid, and the high-pressure cylinder has a pair of electrodes for supplying electricity to the conductive liquid, and applies an external pressure to the conductive liquid from a uniaxial direction. Means, wherein the sintering material contained in the conductive liquid is sintered by at least Joule heating of the conductive liquid while isotropically pressing. .

[0008] As the conductive liquid, for example, mercury can be used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an embodiment of an energized HIP device according to the present invention will be described. In FIG. 1, the current-carrying HIP apparatus has a high-pressure cylinder 10 provided with a heat insulating wall 11 on an inner wall. The bottom of the high-pressure cylinder 10
The lower lid 12 made of a conductive material is closed. High pressure cylinder 1
The upper part of 0 is closed by a movable punch 13 made of a conductive material. An energizing liquid 14 made of a conductive material is accommodated in the high-pressure cylinder 10, and a sintered material 16 is disposed in the energizing liquid 14 in a state of being accommodated in a capsule 15. The type of the sintering material 16 is not particularly limited as long as it can be sintered, and examples thereof include metal powder and ceramic powder. A power supply 17 is connected to the lower lid 12 and the punch 13. As the energizing liquid 14, for example, high-resistance mercury is used, but is not limited thereto. Further, if a material having a higher electric resistance than the sintering material 16 is used as the energizing liquid 14, the sintering material 16 is also energized, and the Joule heat of the sintering material 16 itself can be used. As the power supply 17, a pulse power supply or a DC power supply is used.

In this energizing HIP apparatus, an external pressure, for example, a hydrostatic pressure, is applied to the punch 13 to press the sintered material 16 through the energizing liquid 14. From this, the sintered material 16
In order to pressurize isotropically the capsule 15
1, it is preferable to be arranged so as to be separated from any of the lower lid 12 and the punch 13. Of course, lower lid 12, punch 13
A seal is provided between the cylinder and the high-pressure cylinder 10 so that there is no liquid leakage even under high pressure.

In the heating method, a current-carrying liquid 14 is put around a sintered material 16, and a lower lid 12, a punch 1
Electric current is supplied through the power supply 3 to cause the energized liquid 14 to generate Joule heat. The heat insulating wall 11 may be made of a material having an insulating property not only in heat but also in electrical properties.

With the above structure, the load applied from the punch 13 increases the hydrostatic pressure of the energizing liquid 14, and the current flowing through the energizing liquid 14 generates Joule heat.
Is heated. Then, the pressurized and heated current-carrying liquid 14
Presses and heats the sintered material 16 isotropically.

[0013]

The current-carrying HIP device according to the present invention is capable of rapid heating without a temperature difference between the inside and the outside of the sintered material because of the internal heating by Joule heat of the current-carrying liquid serving as the pressurized medium. Further, since the pressurizing medium is a liquid, the material can be isotropically pressurized and sintered. Therefore, by using the current-carrying HIP device, it is possible to speed up the molding of a sintered product having a complicated shape.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a current-carrying HIP device according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional electric current sintering apparatus.

FIG. 3 is a cross-sectional view illustrating an example of a conventional HIP device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High-pressure cylinder 11 Insulated wall 12, 31 Lower lid 13 Punch 14 Energized liquid 15 Capsule 16 Sintered material 17, 24 Power supply

Claims (2)

[Claims] 1. A high-pressure cylinder containing a conductive liquid,
The high-pressure cylinder is provided with a pair of electrodes for energizing the conductive liquid and means for applying an external pressure to the conductive liquid from a uniaxial direction. A current-carrying HIP apparatus characterized in that sintering is performed by at least Joule heating of the conductive liquid while isotropically pressing the binding material. 2. The current-carrying HIP device according to claim 1, wherein the conductive liquid is mercury.