JPS6035780B2 - End hat for magnetron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an end hat for a magnetron used in a microwave oven or the like.

The magnetron consists of an upper end hat 1 and a lower end hat 1' made of molybdenum, as shown in Figure 3.
It is common to have a main part 2 between which is held a coil 3 made of thorium tungsten. Both end hats 1, 1' are supported by molybdenum glue rods 4, 4' joined to each other, and both ends of the coil 3 are brazed to the two end hats. Conventionally, so-called platinum solder has been used as the brazing material for soldering the coil 3 to the end hat, but this platinum solder is extremely expensive, which increases the manufacturing cost of the magnetron accordingly. . Further, when soldering the coil 3 and the end hat, it was difficult to properly hold the brazing material 5 in a predetermined brazing position, and a great deal of effort was required to prepare for brazing. Instead of the platinum wax mentioned above, a method has been adopted in which a paste-like paste of molybdenum and ruthenium is used as a wax coating, and this is applied to the wax area with a brush for soldering, but the preparation work for the wax coating is inefficient;
A major problem was that it was difficult to obtain a uniform waxy state. The present invention was made in view of the above circumstances, and provides an economically superior end hat that allows efficient soldering work.

This will be explained below. The end hat for a magnetron according to the present invention is characterized in that a brazing material made of a competitive alloy of ruthenium and molybdenum is adhered to the surface of the end hat body.

FIG. 1 shows one embodiment of the end hat for a magnetron according to the present invention, in which a is a sectional view and b is a bottom view. This end hat 1 consists of an end hat la made of molybdenum and a brazing material 5 attached to the end hat body la. The end hat main body la has a flange part lb and a cylindrical part lc protruding from the center of the flange part lb, and the solder filler metal 5 is attached to the lower surface of the flange part lb so as to surround this cylindrical part lc. It is attached. This brazing filler metal 5 is made of a sintered alloy of ruthenium and molybdenum. An alloy of ruthenium (Ru) and molybdenum (Mo) has a ruthenium content of about 42
There is a eutectic point at the point of weight % (hereinafter simply referred to as %), and the eutectic temperature is approximately 1950 o○, so ruthenium-molybdenum alloys with a composition around this point have a combination of wax acidity and heat resistance. Due to this combination, it is suitable as a wax for heat-resistant parts that are exposed to high temperatures. Furthermore, since ruthenium-molybdenum alloys generally have good wetting properties with high melting point metal materials such as tungsten and molybdenum, in this respect as well, they are excellent as brazing materials for heat-resistant members made of these high melting point metal materials. This brazing filler metal can be manufactured, for example, as follows.

That is, first, molybdenum powder and ruthenium powder are mixed in a predetermined ratio, and the obtained mixed powder is press-molded into a predetermined shape. M. The blending ratio of the livedenum powder and the ruthenium powder is preferably such that the composition is near the eutectic point, that is, the ruthenium content is about 32 to 52%. It is more preferable to set the blending ratio such that the content of ruthenium is about 37 to 47%. As the molybdenum powder, for example, a powder having an average particle size of 3 to 5 microns can be used. In addition, as a ruthenium powder, for example, minus 2
A powder of about 0.00 mesh can be used. There are no particular restrictions on the particle size of these raw material powders. Note that a granulating agent, lubricant, and other additives may be added to the mixed powder as necessary. The obtained mixed powder is charged into a predetermined mold and pressure-molded into a predetermined shape (in the illustrated example, a ring shape) using a hydraulic press machine, an automatic press machine, or the like. The molding pressure for this pressure molding should be selected within a range that will provide a molded product with sufficient strength that will not interfere with subsequent processes, and usually a pressure of several tons per square centimeter is adopted. Ru. The obtained molded body is presintered at a relatively low temperature in a non-oxidizing atmosphere such as a vacuum or a hydrogen stream.

When heating the molded product containing a granulating agent etc., there is a risk of cracks occurring in the molded product.
It is preferable to adopt a heating method that raises the temperature to a temperature above (usually 1100 to 1200 oo). It is also good to adopt a temperature increase schedule that maintains the temperature to a certain extent at about 400 qo at which the organic additive scatters. After pre-sintering is completed, main sintering is performed at a high temperature. The main sintering is also carried out in a non-oxidizing atmosphere, such as in a vacuum or in a hydrogen stream, as in the case of the pre-branching. The temperature of this compaction should be such that a compact can be obtained that has enough strength to be used as a brazing material. For example, if held at 1700 qo for several hours, a compact can be obtained that does not pose any practical problems. can get. In this way, a brazing material suitable for use as a brazing material for high-melting point metal materials can be obtained. Other elements may be added to this brazing filler metal within a range that does not impair the effects of the present invention. Note that in order to successfully spread the filler metal throughout the solder saddle, a considerably larger amount of filler metal than is actually required is normally required, but the filler metal of the present invention is a sintered body. Therefore, the density can be lowered appropriately if necessary,
Therefore, there is an advantage that the brazing material can be placed in advance over the entire brazing area without unduly increasing the amount (weight) of the brazing material. Next, this solder filler is attached to the end hat body as shown in Figure 2, but the attachment means for this purpose is to hold the filler metal in a predetermined position during heating for soldering. For example, the brazing material may be bonded to the end hat body using an organic adhesive such as vinyl or urethane, or it may be welded by a method such as spot welding. good.

As mentioned above, when the organic solvent is heated to a high temperature, it gasifies and scatters, but in the illustrated end hat, the brazing material is continuously held down by the coil 3, so that it does not shift from a predetermined position. EXAMPLE An upper end hat 1 as shown in FIG. 1 was manufactured, and a reed shank 4 was welded and a coil 3 was soldered to obtain a main part 2 for a magnetron as shown in FIG. 3.

In Figure 1a, D is 8.5 fences, D2 is 4.07 willows, d is 1.55 ribs, day is 2.0 skins, t is 0.5 pigs, t'
was on the 1.5 side. In addition, the dimensions of the ring-shaped brazing material are: outer diameter 8, inner wall 4.3, thickness 0.3 willow, and this is glued to the molybdenum end hat body la with vinyl adhesive. there was. Waxing is carried out in an electric furnace with a hydrogen atmosphere, and since the waxing material is firmly held in the waxing area, the preparation work for waxing is extremely easy and the entire waxing process is efficient. I was able to do it.

Moreover, the main part 2 for magnetron thus obtained was excellent in both strength and performance. Next, Figure 4 shows the results of measuring the braze saddle strength using ruthenium-molybdenum brazing fillers of various compositions, heating the molybdenum round rods (1.55 mm) M against each other. , 0, × represent the average value, and the vertical bar represents the range of variation in the measured values.

From the same figure, it can be seen that when the ruthenium content is 37 to 47%, the average solder strength is 15 kg/mau or more, and the variation is small, so it is sufficiently suitable for practical use. In this test, soldering was carried out in a hydrogen atmosphere using a butt welding machine (microbutt welding machine, manufactured by Nippon Welding Materials Co., Ltd.).The brazing conditions were (1) a voltage of 1.4V; ) was 1.3V, the electrode spacing was 2 skins, and the current application time was 2 seconds.As is clear from the above explanation, the magnetron end hat according to the present invention is a wax saddle made of molybdenum or the like. Since the brazing material of a suitable composition is pre-adhered to the soldering area, when assembling the magnetron using this material, the brazing work can be done efficiently and a uniform brazing condition can be obtained. .

Furthermore, since the brazing material is made of a ruthenium-molybdenum alloy, which is cheaper than conventional platinum solder, it is economical in this respect as well, making it extremely practical.

[Brief explanation of the drawing]

FIG. 1 shows an example of an end hat for a magnetron according to the present invention, in which a is a sectional view and b is a bottom view. Further, FIG. 2 is a perspective view of the brazing material and the end hat body, and FIG. 3 is a sectional view of the main parts of the magnetron. moreover,
FIGS. 4a and 4b are a graph showing the relationship between the composition of the brazing filler metal and the strength of the brazing filler metal, and an external view of the test piece. 1... Upper end hat, 1'... Lower end hat, la.
... End hat body, 3... Coil, 4, 4'... Lead shank, 5... Brazing metal. Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. An end hat for a magnetron, comprising a brazing material made of a sintered alloy of ruthenium and molybdenum having a ruthenium content of 37 to 47% by weight, attached to the surface of the end hat body. 2. An end hat for a magnetron according to claim 1 or 2, wherein the brazing material is bonded to the end hat body with an organic adhesive. 3. An end hat for a magnetron according to claim 1 or 2, wherein the brazing material is attached to the end hat body by spot welding.