JPH0734104A - Treatment vessel for dehydrogenation of titanium hydride powder and dehydrogenation method - Google Patents

Abstract

PURPOSE:To provide a treatment vessel for dehydrogenation of titanium hydride powder capable of preventing powder to be treated from sticking to the vessel and to provide a dehydrogenation method. CONSTITUTION:When titanium powder is produced by a hydrogenationdehydrogenation method, the inside of a treatment vessel 3 used in a dehydrogenation process is coated with a releasing agent 4 or this agent 4 is laid on the inside of the vessel 3 and titanium hydride powder 2 is housed in the vessel 3. This vessel 3 is then put in a furnace heated to a high temp. and the titanium hydride powder 2 is dehydrogenated by heat treatment in vacuum.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a container and a dehydrogenation container for using a titanium hydride powder in a dehydrogenation heat treatment when the titanium powder as a powder metallurgy raw material is produced by the hydrodehydrogenation method (HDH method). The present invention relates to a chemical heat treatment method.

[0002]

2. Description of the Related Art Titanium alloys have high specific strength, excellent heat resistance and corrosion resistance, and have properties that are extremely effective as materials for aircraft, etc., but have difficulty in workability such as melting, forging, and cutting. There is. Therefore, the powder metallurgy method is promising as a technique for directly manufacturing a semi-finished product having a final shape from the viewpoint of reducing the processing cost and improving the yield. In the case of producing a titanium alloy by powder metallurgy, there are a method of using a mixed powder of pure titanium powder and a titanium mother alloy powder as a raw material, and a method of using a titanium alloy powder. The former method is considered to be an advantageous method because alloys of various compositions can be manufactured at low cost by changing the mixing ratio of both powders.

As a method of producing pure titanium powder, there is generally a method of mechanically directly crushing sponge titanium to obtain metallic titanium to obtain powder, but since sponge titanium is rich in spreadability, it is directly crushed and finely divided. It is difficult to obtain a powder, and even if it is obtained, it has a large chlorine content, which is not preferable for powder metallurgy. On the other hand, there is an atomizing method in which molten titanium is blown off with a gas to produce powder, or a rotating electrode method in which a titanium electrode is rotated and the electrode is melted by plasma or the like and blown off by a centrifugal force to obtain powder. According to these methods, titanium of relatively high purity can be obtained,
There are problems in powder shape, particle size, cost, etc.

For this reason, the raw material titanium is hydrotreated to give a brittle titanium hydride, which is mechanically pulverized into powder and then dehydrogenated by vacuum heating or the like to obtain titanium powder by the HDH method. Is generally adopted. That is, in the HDH method, scrap materials such as titanium sponge, chips of titanium products, and scraps are charged into a heat treatment furnace, hydrogenated at a high temperature in a hydrogen atmosphere under reduced pressure, and further cooled in a hydrogen atmosphere. The hydrogenated titanium thus obtained is extremely brittle and is crushed to a desired particle size by a mechanical crushing method such as a ball mill. After that, a dehydrogenation treatment is performed to remove hydrogen combined with titanium from the titanium hydride powder.

[0005]

In the above dehydrogenation treatment step, titanium hydride powder is stored in a dish-shaped container, charged into a treatment furnace, and heated to a high temperature (preferably 600 to 80) in vacuum.
Heat and cool. At this time, a processing container made of iron or stainless steel is used for convenience of processing or handling. During the heat treatment, sintering of the stored processing powder proceeds, and as a result, the processing powder is processed. Cohesion occurs between the container and the container, making it difficult to peel the treated powder from the container after the process. Therefore, the treated powder and the container that have adhered are forcedly peeled off by mechanically striking them, which causes the following problems. Since the peeling process is troublesome, the productivity is low and the cost is high. The container is deformed by impact and its life is short. The quality of the treated powder deteriorates because the coagulated container material is mixed with the treated powder.

The present invention solves such a problem, and is a container for dehydrogenation treatment of titanium hydride powder and a dehydrogenation treatment method capable of preventing the powder to be treated from adhering to the container for heat treatment. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention has the following features in a method for producing titanium powder by a hydrodehydrogenation method. That is,
(1) A titanium hydride powder used in a dehydrogenation step, which is a processing container containing titanium hydride powder, characterized in that the inner surface of the processing container is coated or laid with a release material. Dehydrogenation treatment container. And (2) in the dehydrogenation step of the hydrodehydrogenation method for producing titanium powder, the titanium hydride powder is housed in a processing container whose inner surface is coated or laid with a mold release material, and the furnace is heated to a high temperature. A method for dehydrogenating titanium hydride powder, which comprises charging and heat treating under vacuum. In the present invention, a mold release material made of a refractory metal may be laid on the inner surface of the processing container, or a mold release material made of a high melting point material may be applied or sprayed.

[0008]

The present invention will be described in detail below. When titanium powder is filled in a container and heat-treated at a high temperature, pseudo-sintering occurs and the powders adhere to each other to form an agglomerate, or the powder becomes an agglomerate and the agglomerate powder adheres to the treatment container and cannot be removed. . Generally, in an iron or stainless steel container that is subjected to a high-temperature (500 ° C. or higher) heat treatment, the adhered powder does not easily separate, and a mechanical means such as beating is required, but it is necessary to use Demolding (peeling) on the inner surface that comes in contact with the powder to be treated
If the material is laid or applied, the powder to be treated and the container can be prevented from adhering to each other, that is, they can be easily peeled off, so that the container is not damaged and the productivity is not lowered.

FIG. 1 schematically shows a dehydrogenation treatment furnace. Inside an outer cylinder 1, a plurality of treatment vessels (trays) 3 containing titanium hydride powder 2 are stacked. Although not shown, the outer tube 1 is connected to a suction tube for creating a vacuum inside, and an indirect heating means such as an electric heater is provided outside the outer tube as in the conventional furnace configuration. Is. FIG. 2 is a cross-sectional view showing the processing container (tray) 3 of the present invention, and a mold release material 4 is installed on the inner surface of the tray 3.

A high melting point material is used as the mold release material 4, and the installation method is, for example, a refractory metal such as Mo or Nb, or Al.
Ceramics composed of oxides such as ₂ O ₃ and nitrides such as BN are formed into a plate shape, which is laid or lined on the inner surface of the tray 3, or directly lined by thermal spraying or the like. Further, a method of applying the above-mentioned ceramic powder by spraying or the like can also be adopted. At this time, the solvent volatilizes at the heating temperature of the titanium powder,
It is necessary to select a material that does not have a quality problem even if it is mixed in titanium powder. The adhesion between the titanium powder and the iron or stainless steel container is due to the solid phase diffusion of both. However, the above-mentioned materials have a significantly lower solid phase diffusion with titanium than iron or stainless steel, and the heat treatment to be used. Almost no adhesion with titanium occurs at temperature.

Although the present invention has been mainly described above in the case of being used for dehydrogenation treatment, the present invention is not limited to this and can be applied to other heat treatments of titanium powder.

[0012]

Example 1 A high-purity boron nitride (BN) spray agent was uniformly applied to the inner surface of a dish-shaped stainless steel container having a diameter of 400 mm and a depth of 50 mm, and then hydrogen was passed through a 45 μm sieve into the container. 5 kg of titanium oxide powder was filled so as to have a uniform thickness. After charging the container into a vacuum heating furnace, the inside of the furnace was evacuated to 10 ⁻³ torr or less. Then, dehydrogenation was performed under vacuum while maintaining the treated powder temperature at about 700 ° C. The degree of vacuum was lowered because hydrogen was generated in the furnace during dehydrogenation, but it gradually recovered and after about 8 hours, the inside of the furnace became 10 ^-2 torr or less. Stop heating at this point,
Ar gas was introduced into the furnace to cool it to room temperature while maintaining the furnace pressure at atmospheric pressure. The treated powder taken out after cooling was pseudo-sintered into a lump state, but there was almost no adhesion to the container,
Even if there was some, it could be easily peeled from the container by tapping.

[0013]

[Comparative Example] On the other hand, in the case of the same treatment without coating the inner surface of the container, the treated powder was pseudo-sintered into a lump state in the container and the adhesion with the container was strong, so that the It had to be manually peeled off by hitting the deposit and the container with a hammer or the like.

[0014]

Example 2 A container similar to that in Example 1 has a thickness of 0.2 on the inner surface.
A pure Mo thin film of mm was laid and the same dehydrogenation treatment as in Example 1 was performed. The treated powder taken out after cooling was pseudo-sintered in a lump state, but almost no adhesion to the container was observed, and it could be easily peeled from the container by hand.

[0015]

As described above, according to the present invention, by improving the processing container, the adhesion of the high-temperature-treated titanium powder to the container is almost eliminated. Therefore, the mechanical peeling step can be omitted to improve the productivity. The production cost is reduced by eliminating the peeling process and extending the life of the processing container.
Further, since the constituent elements of the processing container can be prevented from diffusing into the titanium powder, the quality of the processing powder is improved.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a main part of a dehydrogenation treatment furnace.

FIG. 2 is a sectional explanatory view showing an example of the processing container of the present invention.

[Explanation of symbols]

 1: Outer cylinder 2: Titanium powder 3: Processing container 4: Release material

Front page continuation (72) Inventor Masao Yamamiya 2-6-3 Otemachi, Chiyoda-ku, Tokyo Within Nippon Steel Corporation (72) Inventor Michio Tamura 1 Fuji-cho, Hirohata-ku, Himeji-shi, Hyogo Shin Nippon Steel Hirohata Works Ltd. (72) Inventor Wataru Kagohashi 3-3-5 Chigasaki, Chigasaki City, Kanagawa Prefecture Toho Titanium Co., Ltd. (72) Ryoji Murayama 3-3-5 Chigasaki City, Kanagawa Prefecture Toho Titanium Co., Ltd. (72) Inventor Eiichi Fukasawa 3-5-5 Chigasaki, Chigasaki, Kanagawa Toho Titanium Co., Ltd.

Claims (5)

[Claims] 1. A processing container which is used in the dehydrogenation step of a hydrodehydrogenation method and which contains titanium hydride powder, wherein the inner surface of the processing container is coated or laid with a release material. A characteristic treatment container for dehydrogenation of titanium hydride powder. 2. The processing container for dehydrogenation of titanium hydride powder according to claim 1, wherein a release material made of refractory metal is laid on the inner surface. 3. The processing container for dehydrogenation of titanium hydride powder according to claim 1, wherein a release agent made of a high melting point material is applied to the inner surface. 4. The processing container for dehydrogenation of titanium hydride powder according to claim 3, wherein a release material made of a high melting point material is sprayed on the inner surface. 5. In the dehydrogenation step of the hydrodehydrogenation method for producing titanium powder, the titanium hydride powder is housed in a processing vessel whose inner surface is coated or laid with a mold release material, and is placed in a furnace heated at a high temperature. A method for dehydrogenating titanium hydride powder, which comprises charging and performing heat treatment under vacuum.