JPH0734153A - Molybdenum sintered compact material and molybdenum material - Google Patents

Abstract

PURPOSE:To provide a molybdenum sintered compact material, which is cold- workable and from which a molybdenum material having high dimensional precision can be obtained and further the product having improved reliability and strength can be manufactured at a comparatively low cast and in good yield, can be applied for the electronic component field where heretofore any product is not applied, and also to provide a molybdenum material. CONSTITUTION:The molybdenum sintered compact material consists of 0.003 to 0.7wt.% carbon and the balance substantially molybdenum and comprises Mo particles having <= 25mum average particle size and also has 9.55 to 10.15 specific gravity, at least 900MPa strength and toughness of at least 0.8mm deflection. The molybdenum material, which is obtained by working this molybdenum sintered compact material into final shape with the cold-working, has at least 9.6 specific gravity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molybdenum material which is a refractory metal material used for electronic parts and the like.

[0002]

2. Description of the Related Art Generally, there are two methods for producing a molybdenum member made of metal molybdenum (Mo) or an alloy containing molybdenum (Mo) as a main component (hereinafter, both are simply referred to as Mo material). The method is known.

As a first method thereof, a Mo sintered body material produced by an ordinary powder metallurgy method is hot or cold rolled or swaged and drawn to be processed into a plate or a bar and then cut. Alternatively, it is a method of obtaining a desired shape by performing punching, drawing or the like hot or warm.

The second method is to fill a die made into a product shape with powder and perform compression molding.
This is a method of sintering to obtain a Mo material having a desired shape.

[0005]

The above-mentioned first problem
Although the method of (1) can obtain a product with a high specific gravity, it has a drawback that the manufacturing process is relatively complicated, resulting in high cost.

On the other hand, in the second method, the dimensional accuracy is not so good due to the strain generated during sintering, and it is difficult to obtain the desired accuracy. Therefore, in order to obtain the desired dimensional accuracy, it is necessary to further process this Mo sintered body material.

Conventionally, as a method for processing a Mo sintered body material, there has been proposed a method of heating a sintered body material and a jig to be processed in order to prevent cracks during processing and cracks (Japanese Patent Publication No. 4). -51927 gazette).

However, the heating temperature of the Mo sintered body material is usually 200 to 1000 ° C. depending on the size of the material, but it is difficult to heat the material, and
When the heating temperature is 500 to 600 ° C., oxides are generated on the surface and the surface condition deteriorates.

Regarding the toughness of the Mo sintered body, there has been proposed a method for improving the toughness by vapor-depositing carbon on the surface of the material and then uniformly annealing it (see Japanese Patent Publication No. 56-8100). ), This method does not affect the inside of a large sintered body.

Therefore, the technical problem of the present invention is not to process the Mo sintered body material by heating it so that it has toughness, but the Mo sintered body itself has toughness. M that can be processed to the final shape
o To provide a sintered body material and a Mo material.

[0011]

[Means for Solving the Problems] The inventors of the present invention have toughened by controlling the density, average particle size, and carbon content of the sintered body so that even a large sintered body has sufficient toughness. The present invention has been completed by discovering that a Mo sintered body material having properties can be obtained.

According to the present invention, 0.003 wt% to 0.
A molybdenum sintered body material is obtained which is characterized in that 7 wt% of carbon and the balance substantially consist of molybdenum.

According to the present invention, the molybdenum sintered body material is formed of Mo particles having an average particle size of 25 μm or less, has a specific gravity of 9.55 to 10.15, and a transverse rupture strength of at least 900 MPa, And a molybdenum sintered body material having a toughness with a bending amount of at least 0.8 mm.

According to the present invention, there is obtained a molybdenum material characterized by comprising a molybdenum processed material obtained by processing the molybdenum sintered body material to a final shape by cold working.

According to the present invention, the molybdenum material has a specific gravity of at least 9.6.

Here, in the present invention, cold working means working without heating the material or working jig, and hot working or warm working means working by heating the material or working jig. The difference between hot and warm is the difference in heating temperature, and the boundary was 200 ° C.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) Mo powder was used as a carbon source.
_The test powder was prepared by adding ₂ C so that the carbon content was 1.0 wt% or less. The test powder was pressed into a predetermined shape at 294 MPa and heated in hydrogen at 1700 ° C. for 4 hours to give an outer diameter of 11. Disc-shaped Mo with a thickness of 9 mm and a thickness of 3.0 mm
A sintered body material was obtained. This Mo sintered body material has an inner diameter of 12 mm
The sample was put into a mold and subjected to a sizing test without heating. The properties of the Mo sintered body material at this time and the crack occurrence rate in the sizing test are shown in Table 1 below.

[0019]

[Table 1]

Carbon content less than 0.001 wt% (N
o. 1) or 0.8 wt% or more (No. 5) of the comparative example had a relatively high crack occurrence rate of 1 and 0.8 in the sizing test,
Carbon content is 0.003 to 0.6 wt% (No. 2 to N
o. In the embodiment of the present invention 4), the crack occurrence rate is 0 to
It was as small as 0.4.

(Example 2) Using the powder used in Example 1,
Under the same conditions as in Example 1, a Mo sintered body material for bending (bending) test was made, and the cemented carbide tool standard (CIS 026-1) was used.
983), sample thickness 3.10 to 3.20 m
m, width 7.10 to 7.20 mm, and the bending strength was measured. Here, in the bending test, the bending strength was measured by the method shown in FIGS. 1 (a) and 1 (b). That is, as shown in FIG. 1A, in the support base 10,
The test piece 1 is supported at two points with fulcrums 2 and 3, and the load P
Is pressed through the fulcrum 4 and the jig 5. In addition,
As shown in (b), the test piece to which the load P is applied is bent, and the bending amount S is calculated from the position of the fulcrum 4.
In addition, as shown in FIG. 1 (b) at the time of measurement, when the test piece 1 is in contact with the jig 5, the flexure amount is calculated as the flexure amount at the time of contact, or the load immediately before contact is taken as the fracture value. did. The properties of the Mo sintered body material and the bending test results at this time are shown in Table 2 below.

[0022]

[Table 2]

As shown in Table 2 above, the Mo according to the comparative example
In the sintered body material samples (No. 1 and No. 5), the Mo sintered body material samples (No. 2 to No.
The deflection amount S is smaller than that in 4).

(Example 3) No. 1 used in Example 1 was used. 3 powder, under the same conditions as in Example 1, outer diameter 9.8 mm,
A columnar Mo sintered body material 11a having a thickness of 4.9 mm was prepared. As shown in FIG. 2 (A), this Mo sintered body has an inner diameter of 1
Put in 2mm die 12 and punch without punching 1,1
Then, pressure was applied at 4 to form a disk 11b having an outer diameter of 12 mm and a thickness of 3.17 mm as shown in FIG. 2 (B). Then, Figure 2
As shown in (C), the punch 14 of the die is set to 0.
A punch 15 having a step of 5 mm was used, and as shown in FIG. 2D, pressure was applied again, and a coining test was performed.

In this test, the Mo material 11c was not cracked or broken. The specific gravity at that time is shown in Table 3 below.

[0026]

[Table 3]

As shown in Table 3 above, the density of the Mo material increased when pressure was applied without steps. on the other hand,
The density did not change when pressure was applied with steps.

(Example 4) No. used in Example 1 Using the powder of No. 3, under the same conditions as in Example 1, a large disk having an outer diameter of 69 mm and a thickness of 3.5 mm was made, and this Mo sintered body material was put into a die having an inner diameter of 70 mm and the die was heated. Forged The characteristics of the disk before and after that are shown in Table 4 below. At this time, the Mo material was not cracked or broken.

[0029]

[Table 4]

As shown in Table 4, the density is increased, the warp is corrected, and the surface roughness is improved.

As described above, by using the Mo sintered body material according to the embodiment of the present invention, the final shape can be processed only by cold working. In the processing at this time, the thickness reduction rate was as high as 35%, the density was higher than the Mo sintered body material, the voids were reduced, and the strength was also increased.

[0032]

As described above, according to the present invention, by providing the molybdenum sintered body material with high toughness, cracks and cracks are generated without heating during processing such as sizing and coining. Therefore, it is possible to provide a molybdenum sintered body material that can be prevented from being processed and can be cold worked.

Further, according to the present invention, a molybdenum material having a higher dimensional accuracy than the molybdenum sintered body material can be obtained, and reliability and strength can be improved, and a product can be obtained at a relatively low cost and a high yield. As a result, it has become possible to apply it to the components of electronic components that were not previously applied to sintered products.

[Brief description of drawings]

FIG. 1A and FIG. 1B are views showing a bending test method.

2 (A), (B), (C), and (D) are diagrams sequentially showing a method for processing a Mo sintered body material according to an example of the present invention.

[Explanation of symbols]

 1 Test piece 2, 3, 4 Support point 5 Jig 10 Support stand 11a Sintered body material 11b, 11c Molybdenum material after processing 12 Mold 13, 14, 15 Punch

Claims (4)

[Claims] 1. A material for a molybdenum sintered body, wherein 0.003 wt% to 0.7 wt% of carbon and the balance substantially consist of molybdenum, and the carbon is distributed inside. 2. The molybdenum sintered body material according to claim 1, wherein the molybdenum sintered body material is formed of Mo particles having an average particle diameter of 25 μm or less, has a specific gravity of 9.55 to 10.15, and a transverse rupture strength of at least 900 MPa, And a material for a molybdenum sintered body, which has a toughness of which a bending amount is at least 0.8 mm. 3. A molybdenum material, which comprises a molybdenum processed material obtained by processing the molybdenum sintered body material according to claim 1 to a final shape by cold working. 4. The molybdenum material according to claim 3,
A molybdenum material having a specific gravity of at least 9.6.