JP2540775B2 - Diffusion bonding method and bonding crimping device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffusion bonding method and a pressure bonding device for bonding, which are suitable for use in the case of manufacturing a thin product such as a gas supply nozzle used in a radical reaction type precision cutting device by diffusion bonding. Regarding

[0002]

2. Description of the Related Art As a gas supply nozzle used in a radical reaction type precision cutting apparatus, the applicant of the present invention has previously shown that a plurality of bonding projections Wb are formed inside a bonding peripheral edge Wa as shown in FIG. A pair of mirror-symmetrical nozzle halves (objects to be joined) W, W having a gas introduction port Wd formed outside the gas flow recess Wb while being etched while leaving Wc,
Mutual bonding edges Wa, Wa and mutual bonding protrusions Wc,
Wc is in contact with each other, and the gas flow recesses W are opposed to each other.
An ultra-thin nozzle has been developed in which a gas passage T and a gas ejection port F are formed between a pair of nozzle halves W and W of b and Wb and are integrally diffusion bonded (Japanese Patent Application No. 5-99875).

The nozzle half W is made of a metal plate such as stainless steel, and has a thickness of 0.1 to 1.0 mm, a length of 450 mm or less, a width of 60 mm or less, and an etching depth of the gas flow recess Wb. That is 1/4 of the thickness of the nozzle half W
.About.1 / 2, and the diameter of the joining protrusion Wc is about 0.5 to 1 mm.

By the way, the diffusion bonding is performed by mass transfer between objects to be bonded, and the mass transfer is based on diffusion of atoms and ions in a solid through a contact surface. There are various technical points of diffusion bonding such as cleaning of the bonding surface, processing temperature and time, processing atmosphere (vacuum degree), etc., but if the contact between the bonding surfaces is poor, the bonding will not be performed well. , Will be a defective product.

When the thin products as described above are diffusion-bonded, in the conventional case, as shown in FIG.
W is sandwiched between a pair of contact plates 21 and 21 that have been subjected to a bonding prevention treatment with a chromium oxide film, and is inserted between the substrate 22 and the pressing plate 23, and pressure is applied by a weight 24 for diffusion bonding.

[0006]

However, when the gas supply nozzle described above is pressure-bonded and diffusion-bonded by the conventional method, the nozzle halves W, W are not completely diffusion-bonded.
There was a tendency for gas leakage to occur from portions other than the gas ejection port F. Therefore, as a result of investigating the cause of the bonding failure, there is no problem in cleaning the bonding surfaces of the nozzle halves W, W, the processing temperature / time, the processing atmosphere, etc. It was found that this was caused by the contact failure between the joint surfaces of.

(1) When pressurizing the nozzle halves W, W, the substrate 22, the backing plate 21, the nozzle halves W, W, the backing plate 21, the pushing plate 23, and the weight 24 are stacked in this order.
There is no clear position reference between the nozzle halves W, W and the weight 24, and the position of the center of gravity of the weight 24 slightly changes each time diffusion bonding is performed.

(2) The gas supply nozzle has a large aspect ratio, and if only one set of nozzle halves is pressed by the weight 24, the sitting will deteriorate and become unstable. Therefore, as shown in FIG. It is necessary to arrange the halves W and W side by side. But,
If so, the pressing area becomes large, and it becomes difficult to make the surface pressure distribution uniform over the entire pressing area.

(3) When the two sets of nozzle halves W, W are arranged side by side as shown in FIG. 5, a weight 24 of 50 kg or more is required. Therefore, the weight 24 is divided into several pieces in consideration of the work in the furnace, but the surface pressure distribution changes depending on how the weights 24 are stacked, and the uniformity is impaired.

(4) Abutting plate 21 for the nozzle half W
The chromium oxide film for preventing the diffusion bonding is formed by applying a chemical to the patch plate 21 with a brush or dope and then heat-treating it, so that the thickness of the film is not constant in each part of the patch plate 21. , Make the surface pressure distribution non-uniform. Moreover, since it cannot be machined after the heat treatment, there is no way to correct the above.

An object of the present invention is to provide a diffusion bonding method and a bonding crimping device capable of performing accurate diffusion bonding by making the surface pressure distribution of all the bonding surfaces of the objects to be bonded uniform. Another object of the present invention is to provide a diffusion bonding method and a bonding crimping device that do not require weight and can smoothly perform the in-furnace work of the diffusion bonding furnace. Still another object of the present invention is to provide a bonding crimping device in which the backing plate does not reduce the flatness due to repeated use.

[0012]

In order to achieve the above-mentioned object, the diffusion bonding method of the present invention is such that the objects to be bonded are sandwiched between a pair of patch plates and at least one of the plates and the patch is made of boron nitride. Powder is applied and sandwiched, and this is inserted between the substrate and the pressing plate, and the silicon nitride spring presses the pressing plate toward the substrate so that the objects to be joined can be overlapped with each other through the pressing plate. The structure is such that pressure is applied and diffusion bonding is performed. In the above, the powder of boron nitride is dissolved in an organic solvent and applied to at least one of the object to be joined and the backing plate,
It is preferable to dry the boron nitride and then remove the excessive boron nitride powder.

Further, according to the joining crimping device of the present invention, the base plate and the spring receiving plate having the through holes are inserted into the through holes of the base plate and the spring receiving plate, the nuts are screwed together, and the springs are tightened by the nuts. A plurality of screw rods that move the receiving plate toward the substrate, a pressing plate provided between the substrate and the spring receiving plate, and a pressing plate provided between the spring receiving plate and the pressing plate. A silicon nitride spring, which is sandwiched between a pair of backing plates by being pressed against the substrate and is pressed between the pressing plate and the substrate, pressurizes the objects to be joined. It is preferable that the caul plate is made of the same material as the material to be joined and is annealed.

[0014]

A spring made of silicon nitride has a modulus of elasticity that rapidly decreases when heated to a high temperature by diffusion bonding.
Since the elastic modulus hardly decreases to around 300K,
The objects to be joined can be diffusion-bonded by applying a predetermined pressure to each other without using a weight. Further, the boron nitride powder acts as a bonding prevention layer to prevent the diffusion bonding of the backing plate to the object to be bonded, but the powder adhered to the object to be bonded or the patching plate is freely removed from them to keep the coating thickness constant. Therefore, the surface pressure distribution can be made uniform and the objects to be joined can be brought into good contact with each other. Moreover, when the backing plate made of the same material as the article to be joined is annealed, there is no difference in thermal expansion and contraction between the article to be joined and the backing sheet, and no strain remains on the backing sheet. Since the predetermined surface accuracy is maintained without changing the shape, the backing plate can be used repeatedly.

[0015]

1 to 3 show an embodiment of a bonding crimping device according to the present invention. In these figures, reference numeral 1 is a substrate and 2 is a spring bearing plate. The substrate 1 and the spring bearing plate 2 have substantially the same planar shape, and each of the six through holes 1 is located at the same position.
a and 2a are provided respectively. The base plate 1 and the spring bearing plate 2 are opposed to each other, and the through holes 1a, 2 at the same position are provided.
The threaded rod 3 inserted in a and the nuts 4 and 5 screwed to both ends of the threaded rod 3 are connected to each other.

1 is provided on the upper surface of the substrate 1 and the lower surface of the spring receiving plate 2.
The individual recesses 1b and the six recesses 2b are individually formed, and the spacers 6 are fitted into the recesses 1b of the substrate 1,
Spring seats 7 are fitted in the recesses 2b of the spring receiving plate 2, respectively. The recesses 2b are formed symmetrically on the left and right of the screw rod 3 in FIG. The recess 1b is formed in a long shape by connecting from one end to the other end of the substrate 1, and the other recess 2b is circular.

Reference numeral 9 is a push plate. The push plate 9 is arranged below the spring receiving plate 2. The upper surface of the push plate 9 has 6
A circular recess 9a is formed, and a positioning ring 10 is fitted in each recess 9a. Both the spring seat 7 and the positioning ring 10 are circular and correctly face each other vertically. A circular guide hole 7a is formed in the center of the spring seat 7, and a circular recess 9b is formed in the portion of the push plate 9 facing the guide hole 7a.

Between the spring receiving plate 2 and the pushing plate 9, 6 points each are provided.
The individual central shaft 11, the small-diameter coil spring 12, and the large-diameter coil spring 13 are concentrically provided around the central shaft 11.
The central shaft 11 has protrusions 11a and 11b at both ends, and the protrusion 11a at the upper end is inserted into the guide hole 7a of the spring seat 7, and the protrusion 11b at the lower end is inserted into the recess 9b of the pressing plate 9. Further, the small-diameter coil spring 12 has its upper end abutted on the spring seat 7 and its lower end abutted on the bottom of the recess 9a of the pressing plate 9, and the large-diameter coil spring 13 positions its upper end on the spring seat 7 and its lower end. The rings 10 are brought into contact with each other. The upper end and the lower end of the large-diameter coil spring 13 are locked to the locking portions 7b and 10a provided on the spring seat 7 and the positioning ring 10.

The coil springs 12 and 13 push the push plate 9 downward, and a pair of upper and lower contact plates 15 and 15 are provided between the spacer 14 provided on the lower surface of the push plate 9 and the spacer 6 on the substrate 1.
The object to be joined W, such as the nozzle half, which is inserted by being sandwiched by 15, is pressed.

The material of each member will be described below. The substrate 1, the spring receiving plate 2, the screw rod 3, the nuts 4, 5,
Spring seat 7, push plate 9, positioning ring 10, central shaft 11
Is graphite excellent in heat resistance, the spacers 6 and 14 are made of alumina excellent in heat resistance, chemical resistance and strength, and the coil springs 12 and 13 are made of silicon nitride excellent in heat resistance and strength. The coil springs 12 and 13 have elastic modulus which hardly decreases up to around 1300K, unlike ordinary coil springs made of heat-resistant alloy whose elastic modulus rapidly decreases from around 900K. Incidentally, the coil springs 12 and 13 in the figure have a maximum load of 14 kgf, and a maximum load of 168 kgf (= 14 × 12) can be applied to the article W.

The backing plate 15 is made of the same material as the article W to be joined,
It has been annealed. When the article W to be joined is the nozzle half body made of stainless steel described above, it is manufactured by machining to a thickness of 5 to 8 mm and a parallelism of 1/100 or less. The material of the backing plate 15 is 1000 to 110 before machining.
Anneal at 0 ° C. This process eliminates residual strain,
The backing plate 15 does not change its shape even if it is repeatedly used, and maintains the surface accuracy in a predetermined state. The reason why the backing plate 15 is made of the same material as that of the article to be joined W is that the difference in thermal expansion and contraction is eliminated, and a large thermal strain is not left on the article to be joined W in the heating / cooling process.

Hexagonal boron nitride (h
-BN) powder is applied. This powder is the object W
It prevents diffusion bonding of the backing plate 15 to the. The boron nitride powder is dissolved in an organic solvent and atomized to form a patch 1.
It is good to spray on No. 5 and dry with a dryer. Since the particle diameter of boron nitride is about 1/10000 mm, if it is done as described above, it can be uniformly applied to a thickness of about 1/100 mm, and it sufficiently functions as a bonding prevention film. Since the powder that has adhered too much can be freely removed with a brush or the like, the substantial flatness of the contact plate 15 is not impaired by the powder. The hexagonal boron nitride powder may be applied to the article W to be joined, or both the article W to be joined and the backing plate 15.

Next, one embodiment of the diffusion bonding method according to the present invention will be described together with the operation of the bonding crimping device having the above-mentioned structure. First, loosen each nut 5 sufficiently to make spacers 6,
14 is widened, and the objects to be joined W, W are sandwiched between the contact plates 15, 15 between them and inserted. Needless to say, the surface of each patch plate 15 is previously coated with boron nitride powder. The number of charging stages of the articles W and W to be joined in the figure is "10", but this is arbitrary.

After loading the objects to be joined, each nut 5
Is tightened uniformly with a constant torque. This operation pushes down the spring receiving plate 2, so that each coil spring 1
2 and 13 are compressed and press the respective objects W, W to be joined together via the pressing plate 9, the spacer 14 and the contact plate 15. Since there is a correlation between the pressing force of the coil springs 12 and 13 and the tightening torque of each nut 5 or the compression interval of the spring receiving plate 2 and the pressing plate 9 and the like, reproducibility is very good, and the object Each part of W and W is uniformly pressed to obtain a good contact state.

In practice, a universal material testing machine (for example, testing machine capacity 10 ton, load cell 500 kgf)
Using, the object to be joined W is loaded into the crimping device for joining and crimped. That is, in this case, first, a yokan-shaped iron jig having a concave width and a length equal to the length of the spring receiving plate 2 is placed on the upper surface of the spring receiving plate 2 and the center thereof is pressed by a material testing machine (compressed). The coil springs 12 and 13 are contracted.

Considering that the free lengths of the coil springs 12 and 13 are slightly different and the spring constants of the coil springs 12 and 13 are changed by using the coil springs a plurality of times, the compressive load is controlled by a material test. Use the compressive load indicated by the load cell of the machine.
Therefore, the operation of the nuts 4 and 5 is as follows.

The nut 4 is set so that the screw rod 3 does not protrude downward. Next, a material tester is used to compress and apply a predetermined load. Set the nut 5 so that it touches the upper surface of the spring receiving plate 2. If tightened too much, the load applied to each of the 6 to 8 threaded rods 3 will be different, causing damage to the threaded rod 3. If tightened too much, the load cell's load reading will drop and you can see immediately. Finally, the material testing machine is unloaded.

The article W to be joined is put into a diffusion joining furnace in a state of being pressurized by a pressure bonding apparatus and is diffusion joined as well known. After completion of the diffusion bonding, the objects to be bonded are cooled and then taken out from the furnace as they are, and the nut 5 is loosened and removed from the crimping device.

[0029]

As described above, in the diffusion bonding method according to the present invention, the objects to be joined are sandwiched between a pair of contact plates by applying a powder of boron nitride to at least one of the objects to be bonded and the contact plates. , This is inserted between the substrate and the pressing plate, and the pressing plate is pressed toward the substrate by a spring made of silicon nitride, so that the objects to be bonded are pressed together in the overlapping direction through the contact plate to perform diffusion bonding. Since it is configured, the surface pressure distribution of all the joint surfaces of the objects to be joined can be made uniform, a good contact state can be maintained, and accurate diffusion joining can be performed. Moreover, since no weight is used, the work in the furnace can be smoothly performed.

In addition, the boron nitride powder that acts as a bonding prevention layer can be applied to a backing plate or the like and then the powder that has adhered too much can be easily removed to make the coating thickness constant. It is possible to improve the contact. When the powder of boron nitride is dissolved in a solvent and applied to a patch plate or the like, it can be atomized and sprayed, and the application can be performed uniformly and easily.

In the joining crimping device according to the present invention, the base plate and the spring receiving plate having the through holes are inserted into the through holes of the base plate and the spring receiving plate, and the nuts are screwed into the spring receiving plates. A plurality of screw rods that push the plate toward the substrate; a pressing plate provided between the substrate and the spring receiving plate; and a pressing plate provided between the spring receiving plate and the pressing plate. By being pressed toward, the structure is provided with a silicon nitride spring that is sandwiched between a pair of contact plates and presses the objects to be joined that are inserted between the pressing plate and the substrate, Even in this case, the surface pressure distribution on all the joint surfaces of the objects to be joined is made uniform and a good contact state is maintained.
Diffusion bonding can be performed accurately. Moreover, since no weight is used, the work in the furnace can be smoothly performed.

Further, since the reproducibility is good, it is possible to obtain a product with high reliability of joining and good quality and constant.
When the caul plate is made of the same material as the material to be joined and annealed, no thermal strain remains in the caul plate, and therefore repetitive use becomes possible without impairing reproducibility. In addition, when the above-mentioned nozzle halves were diffusion-bonded using the main bonding pressure bonding apparatus, a good gas supply nozzle without gas leakage could be obtained. Depending on the shape, type, etc. of the objects to be bonded, they may be arranged side by side as shown in FIG. 5 and diffusion bonded.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a bonding crimping device according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a cross-sectional view showing a mounted state of a coil spring.

FIG. 4 is a front view showing an example of an article to be joined.

FIG. 5 is a front view of a conventional bonding crimping device.

[Explanation of symbols]

 1 substrate 1a through hole 2 spring receiving plate 2a through hole 3 screw rod 4 nut 5 nut 9 pushing plate 12 small diameter coil spring 13 large diameter coil spring 15 contact plate W to be joined (nozzle half)

Continuation of the front page (56) Reference JP-A-61-33783 (JP, A) JP-A-5-104258 (JP, A) JP-B 27-2767 (JP, B1) JP-B 60-90639 (JP , B2)

Claims (4)

(57) [Claims] 1. An object to be joined between a pair of pad plates,
The boron nitride powder is applied and sandwiched between at least one of the object to be bonded and the backing plate, which is inserted between the substrate and the pressing plate, and the pressing plate is pressed toward the substrate by a spring made of silicon nitride. A diffusion bonding method, characterized in that the objects are pressed together in a direction in which they overlap each other through a contact plate to perform diffusion bonding. 2. A method in which a powder of boron nitride is dissolved in an organic solvent and applied onto at least one of an object to be bonded and a backing plate, the boron nitride is dried, and then the excessive powder of boron nitride is removed. The diffusion bonding method according to claim 1. 3. A base plate having a through hole and a spring receiving plate, and a nut is screwed into the through hole of the base plate and the spring receiving plate, and the spring receiving plate is pushed toward the base plate by tightening the nut. A plurality of screw rods, a pressing plate provided between the base plate and the spring receiving plate, and a pressing plate provided between the spring receiving plate and the pressing plate, and pressing the pressing plate toward the base plate A crimping device for joining, comprising: a spring made of silicon nitride, which is sandwiched between the contact plates and is inserted between the pressing plate and the substrate to press the objects to be joined together. 4. The bonding crimping device according to claim 3, wherein the backing plate is made of the same material as the material to be bonded and is annealed.