JP3758196B2 - Hot isostatic press - Google Patents

Description

【００２０】
各断熱層Ａ、Ｂ、Ｃをそれぞれ備えたＨＩＰ装置を用いて、圧媒ガスとして酸素２０％、アルゴン８０％の混合ガスを使用して、表２に示す条件でＨＩＰ処理した。
【００２１】
【表２】

【００２２】
ＨＩＰ処理後の各断熱層Ａ、Ｂ、Ｃを構成する最内断熱コップの表面生成物、表面に形成された被膜の厚み、及び酸化被膜形成による断熱層の重量変化を表３に示す。
【００２３】
【表３】

【００２４】
表３からわかるように、断熱層Ａの断熱コップを構成する合金中のアルミニウム含有量が少ないために不安定な酸化被膜が形成され、錆等が剥離して、結果的に重量が減少した。断熱層Ｂでは、ＨＩＰ処理回数が少ないうちは、表面にＡｌ₂ Ｏ₃ の被膜が形成され、ほとんど重量変化もなかったが、ＨＩＰ処理を繰り返すうちに、被膜が剥離し始め、２０回繰り返すと、かなりの重量減少が起こった。一方、断熱層Ｃを用いると、最内断熱コップ内面にはアルミニウムを所定量含有する合金層が設けられているので、表面生成物のうち内側はクロム、ニッケルの酸化物が生成されたが、最表面の表面生成物は安定なＡｌ₂ Ｏ₃ 被膜であったため、繰り返しＨＩＰ処理を行っても断熱層全体としての重量変化はほとんどなかった。
【００２５】
なお、上記実施例では、最内側の断熱コップ２０ｃの内面にのみ合金層を設けたが、外面にも合金層を設けるとなおよい。また、ヒータ保持台、製品載置台についても、酸化により安定なＡｌ₂ Ｏ₃ を生成するような合金層を表面に設けることは、耐酸化性の点から好ましい。
また、上記実施例では、断熱層は倒立コップ形状の断熱コップ２０ａ、２０ｂ、２０ｃから構成されたが、本発明のＨＩＰ装置は複数の金属製断熱コップを備えていればよい。また、断熱コップ間に充填された断熱材繊維１９等は、別に充填しなくてもよい。
【００２６】
【発明の効果】
本発明のＨＩＰ装置は、金属製断熱層の表面に合金層を設けるだけなので、断熱層全体がぶ厚くならず、小型化に対応できる。そして、合金層は高温酸化性の雰囲気で酸化されて安定なＡｌ₂ Ｏ₃ の保護膜が生成されるので、耐酸化性に優れている。
【００２７】
しかも、生成されるＡｌ₂ Ｏ₃ の酸化膜は、断熱層を構成する金属との熱膨張率との差異からひびが入ったりすることがあっても、あらたに表面に露出する合金層の酸化により新たなＡｌ₂ Ｏ₃ の被膜が生成されることから、繰り返し行うＨＩＰ処理に対しても長期にわたって安定なＡｌ₂ Ｏ₃ 被膜を維持できるので、装置の長寿命化に繋がる。
【図面の簡単な説明】
【図１】 ，本発明一実施例に係るＨＩＰ装置の断面模式図である。
【図２】図１のＨＩＰ装置の断熱層の部分拡大図である。
【図３】本発明の他の実施例に係るＨＩＰ装置の断熱層の部分拡大図である。
【図４】従来のＨＩＰ装置の断面模式図である。
【図５】図４のＨＩＰ装置の断熱層の部分拡大図である。
【符号の説明】
１５ 断熱層
２０ａ 断熱コップ
２０ｂ 断熱コップ
２０ｃ 断熱コップ
２１ 合金層[0001]
[Industrial application fields]
The present invention relates to a hot isostatic press used in a medium and low temperature oxygen atmosphere of about 1200 ° C.
[0002]
[Prior art]
Hot isostatic pressing equipment (hereinafter referred to as pressure sintering of metal powder, ceramic powder, etc. by applying temperature and gas pressure simultaneously, and densification processing of precision casting products, ceramic parts, etc. HIP device) has already been used industrially and has a proven track record. In recent years, as new materials such as ceramics and cermet are developed, the range of application is expanding.
[0003]
Japanese Patent Laid-Open No. 61-289287 proposes a HIP device as shown in FIG. The heat insulating layer 1 of this HIP device includes a cylindrical (inverted cup-shaped) ceramic heat insulating cup 3 whose upper end is closed, and an inverted cup-shaped dense material heat insulating material provided outside the ceramic heat insulating cup 3. The heat insulating material 4 is filled between the dense heat insulating cups 2a and 2b.
[0004]
In the heat insulating layer 1 of this HIP apparatus, the ceramic heat insulating cup 3 is exposed to the highest temperature during the HIP process, and therefore ceramics (specifically, alumina (Al ₂ O ₃ )) having excellent heat resistance and oxidation resistance are used. In addition to being used, in order to have a heat insulating effect, it is porous (porosity 30 to 80%) and has a thickness of 5 to 20 mm. As the heat insulating cups 2a and 2b made of the dense material, a heat resistant metal such as stainless steel is used to suppress convection which is generated through the heat insulating cup 3 made of ceramics.
[0005]
[Problems to be solved by the invention]
However, in general, ceramics such as Al ₂ O ₃ are easily broken, and the thickness of the ceramic heat insulating cup 3 is required to be at least 5 mm, which is usually 10 mm or more. For this reason, since the heat insulation layer 1 becomes thick as a whole, it is difficult to reduce the size of the apparatus, and the HIP processing space cannot be effectively used. In addition, since Al ₂ O ₃ constituting the ceramic heat insulating cup 3 and the metal constituting the dense material heat insulating cup 2b on the inner layer side have different coefficients of thermal expansion, in general, as shown in FIG. It is necessary to provide a space 5 for. For this reason, the heat insulation layer 1 tends to become thicker, making it difficult to reduce the size of the entire apparatus. Furthermore, the difference in the coefficient of thermal expansion between Al ₂ O ₃ and metal is not only problematic in terms of downsizing of the above-mentioned apparatus, but also because heat conduction is intensively performed at the contact portion between the two. Easily damaged.
[0006]
On the other hand, when the heat insulating layer 1 is constituted only by the metal heat insulating cups 2a and 2b without providing the ceramic heat insulating cup 3 on the innermost side of the heat insulating layer, the metal heat insulating cup 2a is used in an oxidizing atmosphere such as an oxygen-containing gas. 2b is oxidized, and the generated rust adheres to the treated product, causing adverse effects such as discoloration, alteration, and performance degradation of the treated product.
The present invention has been made in view of the technical background as described above, and an object of the present invention is to provide a HIP device that can be miniaturized with a thin heat insulating layer and can sufficiently withstand an oxidizing atmosphere. There is to do.
[0007]
[Means for Solving the Problems]
The hot isostatic pressing device of the present invention has a heat insulation layer in which a plurality of inverted cup-shaped heat-resistant metal heat insulation cups are concentrically stacked in a high-pressure vessel, and is heated inside the heat insulation layer. In the hot isostatic pressing apparatus in which the apparatus is arranged to form a high-temperature furnace chamber, the inner surface of the heat insulating cup on the innermost side of the heat insulating layer is oxidized to form an Al ₂ O ₃ coating of 50 to 300 μm. An alloy layer having a thickness of 5 mm is provided by thermal spraying.
The alloy layer is preferably composed of a Ni-based alloy containing 3 to 30% by weight of Al or a Fe-based alloy containing 3 to 48% by weight of Al.
[0008]
[Action]
When the HIP process is performed in an oxygen atmosphere using the hot isostatic pressing device of the present invention, the alloy layer provided on the surface of the metal heat insulating layer is oxidized to produce an Al ₂ O ₃ coating. The coating of Al ₂ O ₃ prevents the progress of oxidation, thereby protecting the metal heat insulating layer from the oxidizing atmosphere. Therefore, in the hot isostatic pressing apparatus of the present invention, only a thin alloy layer capable of generating an oxidation-resistant film is provided, so that the apparatus can be miniaturized and can be used in an oxidizing atmosphere.
[0009]
Also, since the coefficient of thermal expansion is different between the generated Al ₂ O ₃ and the metal constituting the heat insulating layer, the Al ₂ O ₃ coating cracks or cracks when the HIP treatment is repeated, but it appears newly on the surface. The alloy layer is oxidized again to produce an Al ₂ O ₃ coating. Therefore, the hot isostatic pressing device of the present invention produces a stable Al ₂ O ₃ coating that can withstand repeated HIP treatment and can be used repeatedly in an oxidizing atmosphere.
[0010]
【Example】
First, an HIP apparatus according to an embodiment of the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 10 denotes a cylindrical pressure vessel, the upper opening of which is sealed with a lid 11, and the lower opening of which is sealed with a lid 12. A pressure medium gas flow hole 13 is formed in the upper lid body 11.
[0011]
An inverted cup-shaped heat insulating layer 15 is disposed in the pressure vessel 10, and a processing chamber 16 provided with a heating device is formed inside the heat insulating layer 15. In the processing chamber 16, the workpiece 18 mounted on the mounting table 17 is subjected to HIP processing.
The heat insulation layer 15 includes a plurality of inverted cup-like heat insulation cups 20a, 20b, and 20c concentrically stacked, and a heat insulation material made of ceramic fiber, heat-resistant glass wool, or a mixed fiber of Al ₂ O ₃ and silica between the heat insulation cups. It is configured by filling fibers 19 and the like. The heat insulating cups 20a, 20b, and 20c are made of a heat-resistant metal material such as heat-resistant SUS, Mo alloy, or Inconel.
[0012]
As shown in FIG. 2, an alloy layer 21 having the following composition is provided on the inner surface of the innermost heat insulating cup 20c. The alloy composition of the alloy layer 21 is an alloy that is oxidized to form a dense Al ₂ O ₃ film on the surface. For example, an alloy such as a Ni-based alloy or an Fe-based alloy containing aluminum is preferably used. The content of aluminum in the alloy is an amount necessary and sufficient for forming a stable Al ₂ O ₃ coating, and the melting point of the alloy is higher than the HIP processing temperature of about 1200 ° C., preferably the melting point of the metal of the heat insulating cup 20c. It is the amount which becomes the same level or more. For example, the aluminum content in the case of a Ni-based alloy is 3 to 30% by weight, and the aluminum content in the case of an Fe-based alloy is 3 to 48% by weight. When the aluminum content is less than 3% by weight, a compound formed by oxidation of the alloy layer has a spinel structure, and a stable oxide film cannot be obtained.
[0013]
Both the Ni-based alloy and the Fe-based alloy may contain about 1 to 25% by weight of Y, Cr or the like as a metal other than aluminum. Specific composition examples of the alloy satisfying such requirements are as follows: (1) Cr 22 wt%, Al 10 wt%, Y 1 wt%, balance Ni Ni-based alloy; (2) Cr 22 wt%, Al 5.8 wt% And Fe-based alloy of the remaining Fe; (3) Fe 22% by weight of Cr, 4.8% by weight of Al, Fe-based alloy of the remaining Fe, and the like. The composition of the alloy is preferably selected so that the thermal expansion coefficient approximates that of the metal constituting the metal heat insulating cup 20c provided with the alloy layer. For example, when using Inconel 601 (melting point: about 1350 ° C.) for the heat insulating cup 20c, the alloy layer 21 is preferably composed of the Ni-based alloy (1) whose thermal expansion coefficient approximates that of Inconel 601.
[0014]
The thickness of the alloy layer 21 is preferably about 50 to 300 μm. If it is too thin, the metal constituting the heat insulating cup 20c and oxygen are likely to come into direct contact with each other, and oxidation of the metal heat insulating cup 20c cannot be sufficiently prevented.
The alloy layer 21 is not particularly limited as long as a thin film within the above range is obtained, and may be formed by a thermal spraying method such as arc spraying or plasma spraying, or may be formed by a PVD method such as a vacuum deposition method. May be. Of these, the thermal spraying method is preferably used because it can easily form a film of about several hundred μm.
[0015]
In the HIP apparatus having the above-described configuration, even when a high-temperature gas containing oxygen flows into the processing chamber 16 during HIP processing, the alloy layer 21 is first oxidized and Al ₂ is formed on the surface of the innermost heat insulating cup 20c. An O ₃ film is formed. Although the alloy layer 21 is composed of an alloy composed of a plurality of metals, since the formation energy of Al ₂ O ₃ is smaller than the formation energy of other metal oxides, aluminum is preferentially oxidized and Al ₂ O is first oxidized. Form ₃ Since the Al ₂ O ₃ coating is dense, when the coating is formed on the surface, the oxidation is prevented from proceeding to the inside. That is, the formed Al ₂ O ₃ film serves as an oxidation-resistant protective film in an oxidizing atmosphere.
[0016]
Therefore, according to the HIP device of the present invention, oxidation that affects the irradiated object even in an oxidizing atmosphere, that is, rust and the like are peeled off does not occur. Moreover, since the alloy layer 21 having a composition that generates Al ₂ O ₃ is only provided on the surface of the heat insulating cup 20c, the space in the processing chamber 16 can be used more effectively than in the case where a ceramic plate or the like is provided. Can cope with downsizing. Furthermore, the former is more difficult to break than the innermost heat insulating cup 20c in which the alloy layer 21 is oxidized to form an Al ₂ O ₃ protective film and the heat insulating cup made of Al ₂ O ₃ itself. Cheap.
[0017]
It is conceivable that a coating of Al ₂ O ₃ is directly provided on the heat insulating cup 20c, but in this case, due to the difference in thermal expansion coefficient between the Al ₂ O ₃ and the metal constituting the heat insulating cup 20c, Al _If the film of ₂ O ₃ is cracked or severe, it will crack and peel off. On the other hand, in the configuration of the present invention, when the HIP treatment is repeatedly performed, even if the previously generated Al ₂ O ₃ film is damaged, the alloy exposed from the damaged portion is oxidized again to produce new Al ₂ O _3. Since a film is formed, a stable Al ₂ O ₃ film can be maintained over a long period of time.
[0018]
Next, the effect of the HIP processing apparatus of the present invention will be described based on a specific example. As the heat insulating layer, three types of heat insulating layers A, B, and C having the metal composition shown in Table 1 were used in the innermost heat insulating cup or alloy layer constituting the heat insulating layer. The heat insulating layers A and B are not provided with an alloy layer on the surface, and Table 1 shows the metal composition constituting the heat insulating cup. The heat insulating layer C is provided with an alloy layer having a thickness of about 200 μm on the surface of the heat insulating cup by a thermal spraying method. Table 1 shows the metal composition of the alloy layer.
[0019]
[Table 1]

[0020]
Using a HIP apparatus provided with each of the heat insulation layers A, B, and C, HIP treatment was performed under the conditions shown in Table 2 using a mixed gas of 20% oxygen and 80% argon as the pressure medium gas.
[0021]
[Table 2]

[0022]
Table 3 shows the surface product of the innermost heat insulating cup constituting each of the heat insulating layers A, B and C after the HIP treatment, the thickness of the film formed on the surface, and the change in the weight of the heat insulating layer due to the formation of the oxide film.
[0023]
[Table 3]

[0024]
As can be seen from Table 3, because the aluminum content in the alloy constituting the heat insulation cup of the heat insulation layer A is small, an unstable oxide film is formed, rust and the like are peeled off, and the weight is reduced as a result. In the heat insulation layer B, when the number of HIP treatments was small, a coating of Al ₂ O ₃ was formed on the surface and there was almost no change in weight, but as the HIP treatment was repeated, the coating began to peel off and repeated 20 times. A considerable weight loss happened. On the other hand, when the heat insulating layer C is used, an inner layer containing an alloy layer containing a predetermined amount of aluminum is provided on the inner surface of the inner heat insulating cup. Since the surface product on the outermost surface was a stable Al ₂ O ₃ coating, there was almost no change in the weight of the entire heat insulating layer even after repeated HIP treatment.
[0025]
In the above embodiment, the alloy layer is provided only on the inner surface of the innermost heat insulating cup 20c. However, it is more preferable that an alloy layer is provided on the outer surface. In addition, it is preferable from the viewpoint of oxidation resistance that the heater holding table and the product mounting table are provided with an alloy layer on the surface that generates stable Al ₂ O ₃ by oxidation.
Moreover, in the said Example, although the heat insulation layer was comprised from the inverted cup-shaped heat insulation cup 20a, 20b, 20c, the HIP apparatus of this invention should just be equipped with the some metal heat insulation cup. Further, the heat insulating fiber 19 and the like filled between the heat insulating cups need not be filled separately.
[0026]
【The invention's effect】
Since the HIP device of the present invention is simply provided with an alloy layer on the surface of the metal heat insulating layer, the entire heat insulating layer does not become thick and can be reduced in size. Since the alloy layer is oxidized in a high-temperature oxidizing atmosphere to form a stable Al ₂ O ₃ protective film, the alloy layer is excellent in oxidation resistance.
[0027]
Moreover, even if the generated Al ₂ O ₃ oxide film cracks due to the difference in coefficient of thermal expansion from the metal that constitutes the heat insulation layer, the oxidation of the alloy layer that is newly exposed on the surface As a result, a new Al ₂ O ₃ film is generated, and thus a stable Al ₂ O ₃ film can be maintained over a long period of time even with repeated HIP treatment, leading to a longer life of the apparatus.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a HIP device according to an embodiment of the present invention.
2 is a partially enlarged view of a heat insulating layer of the HIP device of FIG. 1. FIG.
FIG. 3 is a partially enlarged view of a heat insulating layer of a HIP device according to another embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of a conventional HIP device.
5 is a partially enlarged view of a heat insulating layer of the HIP device of FIG. 4;
[Explanation of symbols]
15 heat insulation layer 20a heat insulation cup 20b heat insulation cup 20c heat insulation cup 21 alloy layer

Claims (3)

In the high-pressure vessel, a heat insulating layer formed by concentrically stacking a plurality of inverted cup-shaped heat-resistant metal heat-insulating cups is disposed, and a heating device is disposed inside the heat-insulating layer to form a high-temperature furnace chamber. In the isostatic press,
On the inner surface of the heat insulating cup on the innermost side of the heat insulating layer, an alloy layer having a thickness of 50 to 300 μm which is oxidized to form an Al ₂ O ₃ coating is provided by thermal spraying. Isotropic pressure device.   The hot isostatic pressing device according to claim 1, wherein the alloy layer is made of a Ni-based alloy containing 3 to 30% by weight of Al.   The hot isostatic pressing device according to claim 1, wherein the alloy layer is made of an Fe-based alloy containing 3 to 48% by weight of Al.

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