201209176 六、發明說明： 關連申請的互相參照 本申請案基於2010年4月1日所申請的日本特許出願 201 0-84801號而主張優先權，其所揭示的全部內容由於參 照而收編於本說明書。 【發明所屬之技術領域】 本發明關於一種鉬合金及其製造方法，更詳細而言， 關於一種鉬合金，其係使用作爲在2000 °C以上的高溫要求 具有足夠強度而在高溫環境下使用的構件的材料；及其製 造方法》 【先前技術】201209176 VI. OBJECTS OF THE INVENTION: CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority based on Japanese Patent Application No. 201-84801, filed on Apr. 1, 2010, the entire disclosure of which is hereby incorporated by reference. . [Technical Field] The present invention relates to a molybdenum alloy and a method for producing the same, and more particularly to a molybdenum alloy which is used as a high temperature at 2000 ° C or higher and which is used in a high temperature environment. Material of component; and manufacturing method thereof [Prior Art]
Mo、W及該等合金具有2000°C以上的熔點，一直以來 ’主要被使用於電子構件、電極材料、燈絲材料等。在近 年來’著眼於該等合金其高溫下的強度及耐蝕性優異，而 期待作爲構造用構件材料的用途。但是由於Mo及W的熔點 非常高，且加工性差，因此難以藉著通常的熔解或加工這 些方法製作出製品。所以在現況中，一般而言藉由粉末燒 結法製造各種構件。 然而’以一般的粉末燒結法所得到燒結體的相對密度 在9 0%左右，所以在其內部會殘留多數氣孔。已知該等金 屬燒結體的強度或耐蝕性等特性會明顯隨著密度而改變， 燒結體內部的氣泡會使強度顯著降低，腐蝕性溶液或氣體 -5- 201209176 滲透至內部的氣泡，而明顯損害耐蝕性。另一方面，燒結 溫度若過高’則結晶粒粗化，而會有強度降低變脆的問題 。所以在現況中，通常藉由熱壓延或熱鍛造這些塑性加工 法，以謀求高密虔化。 以該等方法所製作出的構件，由於在高溫下使用而產 生等軸結晶粒，因此導致高溫下的強度顯著降低、耐久性 惡化。另外，Mo的耐氧化性非常貧乏，因此在成形體中 氧的含量非常高。其結果，在2000 °C左右的高溫環境使用 的情況下，認爲是由於氧氣所造成的氣體產生，而使得構 件的一部分或全體會有發生局部的膨脹的情況。 對於此問題，例如專利文獻1 (日本特開平9-1 96570 號公報）所揭示般，已知藉由鎢（W )的添加可抑制結晶 粒的粗化。但是，這專利文獻1並未明確提及膨脹的發生 。另外，在這專利文獻1的方法中，由於加工步驟複雜， 其製作採用了藉由壓延進行的原料板的製作步驟與熱旋壓 加工，因此導致在製作大型構件時成本增加。 先前技術文獻 專利文獻 專利文獻1:日本特開平9-196570號公報 【發明內容】 本發明人等，這次得到如下述這些見解，藉由在作爲 基體的鉬（Mo)粉末混合Nb、Ta及W之1種或2種以上的 201209176 添加粉末並且固化成形，該添加粉末的量相對於鉬粉末而 言爲20〜50原子％，即使在2000 °C的高溫使用時，也能抑 制局部的膨脹發生及結晶粒粗化而使構件的壽命延長，而 且不需要複雜的加工步驟，也能輕易製作出大型構件。 所以，本發明之目的在於提供一種鉬合金及其製造方 法，其係即使在2000°C的高溫使用時，也能抑制局部的膨 脹發生及結晶粒粗化而使構件的壽命延長，而且不需要複 雜的加工步驟，也能輕易製作出大型構件。 亦即，依據本發明其中一個形態，提供一種鉬合金， 其係在作爲基體的鉬（Mo )粉末混合Nb、Ta及W之1種或 2種以上的添加粉末並且固化成形而得，該添加粉末的量 相對於鉬粉末而言爲20〜50原子％。 另外’依據本發明的另一個形態，提供一種鋁合金之 製造方法’其係包含以熱均靜水壓（HIP )將混合粉末固 化成形，該混合粉末係含有作爲基體的鉬粉末；與Nb、 Ta及W之1種或2種以上的添加粉末，該添加粉末相對於鉬 粉末而百爲20〜50原子°/〇。 【實施方式】 組合金 藉由本發明所得到的鉬合金’係在作爲基體的鉬（Mo, W and these alloys have a melting point of 2000 ° C or higher, and have been mainly used for electronic members, electrode materials, filament materials and the like. In recent years, attention has been paid to the excellent strength and corrosion resistance of these alloys at high temperatures, and it is expected to be used as a structural member material. However, since Mo and W have a very high melting point and poor workability, it is difficult to produce a product by ordinary melting or processing. Therefore, in the present state, various members are generally manufactured by powder sintering. However, the relative density of the sintered body obtained by the general powder sintering method is about 90%, so that many pores remain in the inside. It is known that the properties such as strength or corrosion resistance of these metal sintered bodies change significantly with density, and the bubbles inside the sintered body cause a significant decrease in strength, and the corrosive solution or gas -5 - 201209176 penetrates into the internal bubbles, which is obvious. Damage to corrosion resistance. On the other hand, if the sintering temperature is too high, the crystal grains are coarsened, and there is a problem that the strength is lowered and becomes brittle. Therefore, in the current state, these plastic working methods are usually performed by hot rolling or hot forging to achieve high density. The member produced by these methods produces equiaxed crystal grains by use at a high temperature, so that the strength at a high temperature is remarkably lowered and the durability is deteriorated. Further, Mo is extremely poor in oxidation resistance, so that the content of oxygen in the formed body is very high. As a result, in the case of use in a high-temperature environment of about 2000 °C, it is considered that gas is generated by oxygen, and partial expansion of a part or the whole of the member may occur. For example, as disclosed in Japanese Laid-Open Patent Publication No. Hei 9-1 96570, it is known that the coarsening of crystal grains can be suppressed by the addition of tungsten (W). However, this Patent Document 1 does not explicitly mention the occurrence of expansion. Further, in the method of Patent Document 1, since the processing steps are complicated, the production process of the raw material sheet by the rolling and the hot spinning processing are employed, resulting in an increase in cost when manufacturing a large-sized member. In the present inventors, the present inventors have obtained the following findings by mixing Nb, Ta, and W with molybdenum (Mo) powder as a matrix. One or two or more kinds of 201209176 are added and solidified, and the amount of the added powder is 20 to 50 atom% with respect to the molybdenum powder, and local expansion can be suppressed even when used at a high temperature of 2000 °C. The coarsening of the crystal grains allows the life of the members to be extended, and large-scale members can be easily produced without complicated processing steps. Therefore, an object of the present invention is to provide a molybdenum alloy and a method for producing the same, which can suppress the occurrence of local expansion and coarsening of crystal grains even when used at a high temperature of 2000 ° C to extend the life of the member, and does not require Larger components can also be easily fabricated with complex machining steps. That is, according to one aspect of the present invention, there is provided a molybdenum alloy obtained by mixing a molybdenum (Mo) powder as a substrate with one or more kinds of added powders of Nb, Ta and W, and solidifying and molding the same. The amount of the powder is 20 to 50 atom% with respect to the molybdenum powder. In addition, according to another aspect of the present invention, a method for producing an aluminum alloy is provided, which comprises solidifying a mixed powder by a hot hydrostatic pressure (HIP) containing a molybdenum powder as a matrix; and Nb, One or two or more kinds of added powders of Ta and W, and the added powder is 20 to 50 atom%/〇 with respect to the molybdenum powder. [Embodiment] Group of alloys The molybdenum alloy obtained by the present invention is attached to molybdenum as a matrix (
Mo )粉末混合作爲第二相的添加粉末並且固化成形所得 〇 作爲基體的鉬（Mo)粉末爲純鉬的粉末，容許含有Mo) powder is mixed as a powder of the second phase and solidified by molding. The molybdenum (Mo) powder as a matrix is a pure molybdenum powder, and is allowed to contain
S 201209176 不可避免的雜質。鉬粉末係以具有6〜30μπι的平均粒徑爲 佳，較佳爲1〇〜20μηι。基體的平均粒徑若在6μπι以上，則 成形時的充塡變得極佳，可得到實際使用時所要求足夠的 密度，強度提升。另外還可有效迴避鉬中的氧含量增加而 成爲膨脹發生的主要原因。基體的平均粒徑若在30 μιη以 下，則第二相的分散狀態良好，可有效地防止局部密度降 低。 作爲第二相的添加粉末爲Nb、Ta及W之1種或2種以上 的粉末，容許含有不可避免的雜質。此添加粉末的添加量 ，相對於作爲基體的鉬粉末而言爲20〜50原子％，宜爲20 〜40原子％。使用Nb、Ta及/或W作爲添加粉末的理由在於 ，藉由使滿足這兩個條件：第1，在高溫下不會熔融；第2 ，在高溫下的強度優異的第二相粒子分散在內，可抑制基 體的鉬相的結晶粒粗化，且可提高在高溫下的強度。添加 粉末的添加量若未達2 0原子％，則會有無法得到足以承受 所產生的氣體壓力的強度的情況。另外，添加量若超過50 原子％，則其效果達飽和。 添加金屬粉末的平均粒徑係以15〜50μιη爲佳，較佳 爲30〜50μιη。平均粒徑若在15μηι以上，則可減少因爲在 結晶粒界的缺口效應等所造成局部強度減弱的部分，而抑 制氣體通過粒界而聚集的現象，藉此可充分提升抑制膨脹 的效果。平均粒徑若在5 Ομιη以下，即可防止燒結性降低 ，在HIP後可得到夠高的密度。另外，鉬粉末及添加粉末 的平均粒徑，係藉由雷射繞射法所測得體積基準粒徑分布 -8 - 201209176 中5 0%粒徑的D50 » 將這些原料粉末混合並且固化成形所得到的鉬合金， 係以由Nb、Ta及W之1種或2種以上、與剩餘部分的Mo及 不可避免的雜質所構成（consisting of)爲佳。 製造方法 藉由本發明所得到的鉬合金之製造方法，係包含以熱 均靜水壓（HIP)將混合粉末固化成形，該混合粉末係含 有作爲基體的鉬粉末、與Nb、Ta及W之1種或2種以上的添 加粉末，該添加粉末相對於鉬粉末而言爲20〜50原子 此HIP處理，係以藉由將混合粉末保持在處理溫度 1100〜2100 °C及壓力50〜300MPa的條件下30分鐘〜24小 時而進行爲佳，以藉由保持在處理溫度1200〜1700 °C及壓 力100〜200MPa的條件下1〜10小時而進行爲較佳。處理 溫度若在ll〇〇°C以上，則密度顯著變高，溫度若在2100°C 以下，即可迴避實際應用時設備方面的成本提高。另外， 在HIP溫度超過1 400°C的條件下，SC製容器會因爲處理溫 度而熔融，因此使用市售的鉬、鈮或鉬等高熔點材質的板 材，製作出與SC製容器相同尺寸的容器，使用HIP處理爲 佳。 另外，壓力若在50MPa以上即可得到夠高的密度，壓 力只要在300MPa以下，即可迴避實際應用時設備方面的 成本提高。進一步而言，保持時間若在30分鐘以上，即可 得到足夠的密度，在24小時以下’即可有效地防止結晶粒 -9- 201209176 的粗化。 如以上所述’以相對於作爲基體的鉬粉末而言爲20〜 50原子％的量，混入平均粒徑爲15〜50μηι的Nb、Ta及W之 1種或2種以上的添加粉末，而製成HIP成形體，藉此可抑 制在2000 °C左右的高溫環境所產生的膨脹。進一步而言， 藉由添加第二相，可得到結晶粒微細化的效果，並且因爲 藉由HIP法製作而成爲非等軸結晶粒，所以能夠使構件的 壽命延長。 [實施例] 以下藉由實施例對本發明作具體說明。各種添加粉末相 對鉬粉末的組成如表1所揭示，將其混合而得的粉末20kg 充塡至直徑25 0mm而高度80mm的圓柱形HIP用鐵製囊體， 並且脫氣密封。在處理溫度1350 °C、壓力147MPa、保持 時間5小時及加壓媒介爲Ar的條件下，對此囊體實施HIP處 理，製作出直徑200mm而厚度40mm的成形體。對於以這 樣的方式所得到的成形體進行以下評估。 評估1 :成形體密度 針對所製作出的成形體評估相對密度（％ )。此相對 密度，係藉由將所製作出的成形體的密度與純鉬成形體的 成形體密度比較評估而決定。將其結果揭示於表1。 評估2:符合實際使用環境的評估 -10- 201209176 爲了進行符合實際使用環境的評估，使用碳加熱器， 在2〇oo°c、不活性環境下，對於成形體實施熱處理。對於 實施此熱處理的成形體，評估在2000°c熱處理後的膨脹及 作爲基體..的鉬的.結..晶粒徑.。.將屬等結果揭示..於表1。 關於腫脹，以目視觀察在2000 °c熱處理後的氣體有無 造成構件局部的膨脹。其結果之中，將並未觀察到局部腫 脹的情形評爲〇、觀察到局部腫脹的情形評爲X。 關於熱處理後結晶粒徑（μιη )，將硏磨面腐蝕，並 以光學顯微鏡拍攝照片，在此照片畫上—定長度的測試直 線’測定此直線與結晶粒界的交點數目，[測試直線長度 (μιη) ]/[交點數目（個）]，藉此進行評估。S 201209176 Inevitable impurities. The molybdenum powder is preferably an average particle diameter of 6 to 30 μm, preferably 1 Å to 20 μm. When the average particle diameter of the substrate is 6 μm or more, the filling at the time of molding becomes excellent, and a sufficient density and strength can be obtained in actual use. In addition, it is possible to effectively avoid the increase in the oxygen content in the molybdenum and become the main cause of the expansion. When the average particle diameter of the substrate is 30 μm or less, the dispersion state of the second phase is good, and the local density can be effectively prevented from being lowered. The powder to be added as the second phase is one or two or more kinds of powders of Nb, Ta and W, and it is allowed to contain unavoidable impurities. The amount of the added powder to be added is 20 to 50% by atom, preferably 20 to 40% by atom, based on the molybdenum powder as the matrix. The reason why Nb, Ta, and/or W are used as the additive powder is to satisfy the above two conditions: first, it does not melt at a high temperature; second, second phase particles excellent in strength at a high temperature are dispersed in In this case, coarsening of crystal grains of the molybdenum phase of the matrix can be suppressed, and the strength at a high temperature can be improved. If the amount of the added powder is less than 20% by atom, the strength sufficient to withstand the pressure of the generated gas may not be obtained. In addition, if the amount added exceeds 50 atom%, the effect is saturated. The average particle diameter of the metal powder to be added is preferably 15 to 50 μm, preferably 30 to 50 μm. When the average particle diameter is 15 μm or more, the portion where the local strength is weakened by the notch effect of the crystal grain boundary or the like can be reduced, and the phenomenon that the gas aggregates through the grain boundary can be suppressed, whereby the effect of suppressing the expansion can be sufficiently enhanced. When the average particle diameter is 5 Ομηη or less, the sinterability can be prevented from being lowered, and a high density can be obtained after HIP. In addition, the average particle diameter of the molybdenum powder and the added powder is the D50 of the 50% particle diameter in the volume-based particle size distribution -8 - 201209176 measured by the laser diffraction method. The obtained molybdenum alloy is preferably composed of one or two or more of Nb, Ta and W, and the remaining part of Mo and unavoidable impurities. Manufacturing Method The method for producing a molybdenum alloy obtained by the present invention comprises solidifying a mixed powder containing a molybdenum powder as a matrix and Nb, Ta and W as a matrix by a hot hydrostatic pressure (HIP). Or two or more kinds of added powders, the added powder is 20 to 50 atoms with respect to the molybdenum powder, and the HIP treatment is carried out by maintaining the mixed powder at a treatment temperature of 1100 to 2100 ° C and a pressure of 50 to 300 MPa. It is preferably carried out in the next 30 minutes to 24 hours, and it is preferably carried out by maintaining the treatment temperature at 1200 to 1700 ° C and a pressure of 100 to 200 MPa for 1 to 10 hours. If the treatment temperature is above ll 〇〇 °C, the density will become significantly higher, and if the temperature is below 2100 ° C, the cost of equipment in practical applications can be avoided. In addition, when the HIP temperature exceeds 1 400 ° C, the SC container is melted by the processing temperature. Therefore, a commercially available high-melting material such as molybdenum, niobium or molybdenum is used to produce the same size as the SC container. Containers, preferably treated with HIP. In addition, if the pressure is 50 MPa or more, a high density can be obtained, and if the pressure is 300 MPa or less, the cost of the equipment in practical use can be avoided. Further, if the holding time is 30 minutes or longer, a sufficient density can be obtained, and under 24 hours or less, the coarsening of the crystal grains -9 - 201209176 can be effectively prevented. As described above, the amount of the additive powder of Nb, Ta, and W having an average particle diameter of 15 to 50 μm is mixed in an amount of 20 to 50 atom% with respect to the molybdenum powder as the substrate, and The HIP molded body is formed, whereby expansion at a high temperature environment of about 2000 ° C can be suppressed. Further, by adding the second phase, the effect of refining the crystal grains can be obtained, and since the non-equal crystal grains are produced by the HIP method, the life of the members can be extended. [Examples] Hereinafter, the present invention will be specifically described by way of examples. The composition of each of the added powders relative to the molybdenum powder was as shown in Table 1, and 20 kg of the powder obtained by mixing them was filled into a cylindrical HIP iron capsule having a diameter of 25 mm and a height of 80 mm, and was degassed and sealed. The capsule was subjected to HIP treatment under the conditions of a treatment temperature of 1,350 ° C, a pressure of 147 MPa, a holding time of 5 hours, and a pressurized medium of Ar to prepare a molded body having a diameter of 200 mm and a thickness of 40 mm. The following evaluation was performed on the molded body obtained in this manner. Evaluation 1: Shaped body density The relative density (%) was evaluated for the formed shaped body. This relative density is determined by comparing the density of the formed compact to the density of the molded body of the pure molybdenum molded body. The results are disclosed in Table 1. Evaluation 2: Evaluation in accordance with the actual use environment -10- 201209176 In order to carry out the evaluation in accordance with the actual use environment, heat treatment is applied to the formed body in a 2 〇 ° ° C, inactive environment using a carbon heater. For the shaped body subjected to this heat treatment, the expansion after the heat treatment at 2000 ° C and the crystal grain size of the molybdenum as the matrix were evaluated. The results of the genus are revealed. Regarding the swelling, it was visually observed whether or not the gas after the heat treatment at 2000 °C caused local expansion of the member. Among the results, the case where no local swelling was observed was evaluated as 〇, and the case where local swelling was observed was evaluated as X. Regarding the crystal grain size (μιη) after heat treatment, the honing surface was etched, and a photograph was taken with an optical microscope, and the number of intersections of the straight line and the crystal grain boundary was measured on this photograph--a test line of a fixed length, [test straight length (μιη) ] / [number of intersections (number)], by which evaluation is performed.
S -11 - 201209176 [表1]S -11 - 201209176 [Table 1]
No Mo粉末的 平均粒徑 (#ra) 添加 粉末 ① 量 (at%) 添加份未的 平均粒徑 (#m) 添加 粉末 ② 添加量 (at%) 添加粉末的 平均粒徑 (^m) 成形體 密度 (%) 在20001C 熱處理 後膨脹 熱處雜 晶粒徑 (βία) 1 8 W 20 35 — — 一 99.2 〇 43 2 11 W 30 35 — - - 99.0 〇 40 3 8 Nb 20 35 — — - 99.5 〇 33 4 8 Ta 20 35 — - — 99.3 〇 *50 5 11 Ta 30 35 — 一 — 99.5 〇 57 6 8 w 10 35 Nb 10 40 99.4 〇 43 7 8 w 10 45 Nb 15 25 99.3 〇 50 8 9 w 20 45 Nb 30 25 99.0 〇 50 9 7 w 10 40 Ta 30 23 99.2 〇 45 10 8 w 20 40 Ta 30 38 99.0 〇 44 11 7 Ta 5 35 Nb 40 45 99.0 〇 51 12 8 Ta 15 45 Nb 5 30 99.4 〇 40 13 6 W 10 35 — - 一 99.4 X 57 14 8 w 20 13 — - — 99.3 X 50 15 4 w 30 35 — 一 — 99· 1 X "50 16 35 w 10 35 — - - 97.5 X 56 17 7 w 5 10 Nb 10 11 99.5 X 56 18 4 w 20 60 Ta 20 52 96.2 〇 47 19 45 Ta 30 45 Nb 30 30 95.7 〇 60 20 10 — - - — — 一 99.9 X 500 如表1所不般，在No.20爲純Mo的情況下，在2000 °c 熱處理後觀察到膨脹，熱處理後結晶粒徑大。No.13的添 加量少，因此在2000 °C熱處理後觀察到膨脹，且熱處理後 結晶粒徑稍大。N 〇. 1 4的添加粉末的平均粒徑小，因此在 2000C熱處理後觀察到膨脹。No.15的Mo粉末的平均粒徑 小，因此在2000°C熱處理後觀察到膨脹。 Νο·16的Mo粉末的平均粒徑大，且添加粉末的添加量 少’因此成形密度低’且在200(TC熱處理後觀察到膨脹， •12- 201209176 熱處理後結晶粒徑梢大。No . 1 7的添加粉末的添加量少’ 且添加粉末的平均粒徑小，因此在2000 °C熱處理後觀察到 膨脹，熱處理後結晶粒徑稍大。No. 18的Mo粉末的平均粒 徑小，且添加粉末的平均粒徑大，因此成形密度低。Average particle size of No Mo powder (#ra) Addition of powder 1 amount (at%) Addition of average particle size (#m) Addition of powder 2 Addition amount (at%) Addition of powder average particle diameter (^m) Forming Bulk Density (%) The particle size of the expansion heat at 20001C after heat treatment (βία) 1 8 W 20 35 — — a 99.2 〇 43 2 11 W 30 35 — - - 99.0 〇 40 3 8 Nb 20 35 — — - 99.5 〇33 4 8 Ta 20 35 — — — 99.3 〇*50 5 11 Ta 30 35 — 一 — 99.5 〇57 6 8 w 10 35 Nb 10 40 99.4 〇43 7 8 w 10 45 Nb 15 25 99.3 〇50 8 9 w 20 45 Nb 30 25 99.0 〇50 9 7 w 10 40 Ta 30 23 99.2 〇45 10 8 w 20 40 Ta 30 38 99.0 〇44 11 7 Ta 5 35 Nb 40 45 99.0 〇51 12 8 Ta 15 45 Nb 5 30 99.4 〇40 13 6 W 10 35 — — a 99.4 X 57 14 8 w 20 13 — — — 99.3 X 50 15 4 w 30 35 — 一 — 99· 1 X "50 16 35 w 10 35 — - - 97.5 X 56 17 7 w 5 10 Nb 10 11 99.5 X 56 18 4 w 20 60 Ta 20 52 96.2 〇47 19 45 Ta 30 45 Nb 30 30 95.7 〇60 20 10 — — — — — A 99.9 X 500 As shown in Table 1 In the case where No. 20 is pure Mo After heat treatment at 2000 ° c after the expansion was observed, crystallization heat treatment a large particle size. No. 13 was added in a small amount, so expansion was observed after heat treatment at 2000 °C, and the crystal grain size was slightly larger after the heat treatment. The average particle diameter of the added powder of N 〇. 14 was small, so expansion was observed after heat treatment at 2000C. Since the Mo powder of No. 15 had a small average particle diameter, expansion was observed after heat treatment at 2000 °C. The Mo powder of Νο·16 has a large average particle diameter, and the addition amount of the added powder is small, so the molding density is low, and 200 (the expansion is observed after the TC heat treatment, and the crystal grain size is large after the heat treatment of 12 to 201209176. Since the addition amount of the added powder of 1 7 is small and the average particle diameter of the added powder is small, expansion is observed after heat treatment at 2000 ° C, and the crystal grain size is slightly larger after heat treatment. The average particle diameter of the Mo powder of No. 18 is small. Further, since the added powder has a large average particle diameter, the molding density is low.
No.19的Mo粉末的平均粒徑大，且添加粉末的添加量 多，因此成形密度低、熱處理後結晶粒徑大。相對於此， No.1〜12任一者的Mo粉末的平均粒徑、添加粉末的添加 量、添加粉末的平均粒徑皆滿足本發明適合範圍的條件， 可知其成形體密度高、在200(TC熱處理後並未觀察到膨脹 ，且熱處理後結晶粒徑小》 如此，藉著在Mo粉末中添加高溫下強度高的W粉末等 ，可得到夠高的強度而足以承受所產生氣體的壓力，而能 夠抑制構件的變形。另外，即使在2000 °C的高溫使用時， 也能抑制局部的膨脹發生及結晶粒粗化而使構件的壽命延 長，而且不需要複雜的加工步驟，也能輕易製作出大型構 件。再者，在以往的方法中，使用於高溫熔解的用途（約 2 000 eC )時，需要進行高溫熱處理步驟而導致成本提高， 然而在本發明中不需要這些步驟，而能夠發揮極優異的效 果0 -13-The Mo powder of No. 19 has a large average particle diameter and a large amount of added powder, so that the molding density is low and the crystal grain size after heat treatment is large. On the other hand, the average particle diameter of the Mo powder, the addition amount of the added powder, and the average particle diameter of the added powder of any of Nos. 1 to 12 satisfy the conditions of the present invention, and it is found that the molded body has a high density of 200. (The expansion is not observed after the TC heat treatment, and the crystal grain size after the heat treatment is small.) By adding a W powder having a high strength at a high temperature to the Mo powder, a high enough strength can be obtained to withstand the pressure of the generated gas. In addition, even when used at a high temperature of 2000 °C, it is possible to suppress local expansion and coarsening of crystal grains, thereby prolonging the life of the member, and it is easy to perform complicated processing steps. In the conventional method, when it is used for high-temperature melting (about 2 000 eC), a high-temperature heat treatment step is required to increase the cost. However, in the present invention, these steps are not required, and Play extremely good results 0 -13-