JPS6367540B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a molybdenum material having excellent high-temperature strength. [Technical background of the invention and its problems] Molybdenum materials that have a high recrystallization temperature and high strength after recrystallization are generally used for parts used at high temperatures such as furnace heaters and deposition boats. . However, among molybdenum materials, for example, conventional molybdenum heaters, molybdenum has a high melting point, so it is heavily used in high-temperature (~1800℃) vacuum furnaces, reducing atmosphere furnaces, etc. However, at such high temperatures in practical use, the heater is oxidized by the unavoidable partial pressure of oxygen, deteriorating the surface of the heater, and even breaking, resulting in a shortened lifespan. Further, similar problems may occur with anchor support materials and magnetron center support materials. The anchor support material is a support member that supports the middle part of the filament of a light bulb so as not to deform it.The magnetron center support material is a support member that is provided so as to penetrate the spiral heat radiator of the magnetron, and is used to support the filament of the light bulb so that it does not deform. It is a material that supports the body in a fixed manner. These materials are made of molybdenum, similar to the heater material described above, but there is room for improvement in terms of surface oxidation and deformation of the materials. Furthermore, when a molybdenum boat is used as an evaporation source boat and aluminum is evaporated onto semiconductor devices, etc., the molybdenum boat comes into contact with molten aluminum and undergoes physical changes, resulting in deformation and cracking. Ta. [Object of the Invention] The first object of the present invention is to provide a molybdenum material that has excellent oxidation resistance at high temperatures and has a long life. The aim is to provide materials. [Summary of the Invention] In order to achieve the above object, the present invention provides a molybdenum material having at least a surface portion having long crystals. As a result of research into surface deterioration of molybdenum heaters and vapor deposition boats, the inventors of the present application found that surface oxidation and embrittlement due to molten aluminum occur mainly along grain boundaries. The present invention was completed based on the knowledge that by forming long crystals on at least the surface of a molybdenum heater, the oxidation path or the penetration path of molten aluminum is lengthened, and the time required for surface deterioration is lengthened. The surface portion in the present invention refers to a depth of 0.1 mm from the surface portion, and the greater the depth, the more effective the present invention is. Specifically, it is preferably 1 mm or more, and more preferably 5 mm or more. Further, the molybdenum material of the present invention is effective in preventing surface oxidation and deterioration due to molten aluminum, and is also extremely effective in preventing creep deformation. Therefore, due to the combination of these effects, the molybdenum material of the present invention has a long life. From this point of view, it is desirable that the molybdenum material has long crystals formed throughout. Next, we will discuss long crystals. The longer the crystals are, the smaller the deterioration and embrittlement of the molybdenum material can be. However, L/W is practically preferably 10 or more, and more preferably 20 or more. Here, L is the maximum diameter of the crystal,
W is the minimum width of the crystal. The molybdenum alloy capable of forming long crystals is, for example, one or more selected from compounds of aluminum, silicon, and potassium in a total amount of 0.005 to 0.75% by weight in terms of the amount of aluminum, silicon, and potassium. desirable. Examples of the aluminum, silicon, and potassium compounds include oxides, chlorides, and silicone tungstates. In addition to potassium, silicon, and aluminum, lanthanum, cerium, desprosium, yttrium, thorium, titanium, zirconium,
By containing one or more of niobium, tantalum, vanadium chromium, and magnesium oxides, carbides, or nitrides in a total amount of 0.3 to 3% by weight, the high temperature strength is further improved, making it an effective molybdenum material. Can be provided. A preferred method for producing the molybdenum material of the present invention is as follows:
This is a method in which a molybdenum alloy is sintered, hot worked, and then recrystallized by heat treatment. The hot working is preferably carried out at a working rate of 85% or more, more preferably 90% or more. Further, the temperature range of the recrystallization heat treatment is preferably from 100°C higher than the recrystallization temperature to 2200°C, and more preferably from 200°C higher than the recrystallization temperature to 2100°C. The above treatment allows recrystallized grains to grow long and large. [Embodiments of the Invention] Example 1 Three types of aluminum, silicon, and potassium are added to molybdenum powder in the form of a solution so that they can be uniformly mixed with the molybdenum powder, and when this is dried, the content of the additional elements in the molybdenum powder is determined. The amounts are respectively in the form of aluminum oxide, silicon oxide and potassium chloride.
Contains three types at the same time at 0.015% by weight. Molybdenum powder was press-molded at a pressure of 2 tons/cm ² and then sintered in a hydrogen furnace at 1830°C for 5 hours. This sintered body was rolled in a temperature range of 1,100°C to 1,400°C, and then wire-drawn in a temperature range of 300°C to 1,100°C to obtain a wire body of 6 mmφ. The processing rate of this wire is
It was 95%. Next, from the recrystallization temperature of this wire,
This wire was heat-treated for 2 hours at a temperature of 2000°C, which is 350°C higher, to create a heater for an electric furnace. This heater was formed entirely of long crystals with an L/W of 30. The contents of aluminum, silicon, and potassium in this heater were 0.005% by weight, 0.003% by weight, and 0.007% by weight, respectively. As a comparative example, a molybdenum heater with L/W of 1.3 was created. The thus obtained electric furnace heater of the present invention and the heater of the comparative example were each placed in a reducing atmosphere furnace (atmosphere
It was attached to the wall of a furnace (N ₂ + H ₂ ) and used at 1300°C. As a result, the electric furnace heater of the present invention had no heater breakage even after 6 years had passed, and the surface did not deteriorate due to wear and tear. On the other hand, the heater of the comparative example broke after one year and became unusable. As is clear from the above results, the electric furnace heater of the present invention has excellent oxidation resistance at high temperatures and has a long life compared to conventional molybdenum heaters. Example 2 A sintered body was obtained in the same manner as in Example 1. This sintered body
Hot forged in the temperature range of 1100℃~1400℃, then
A boat material was obtained by hot rolling in a temperature range of 300°C to 1100°C. The processing rate of this boat material was 95%. Next, 350℃ higher than the recrystallization temperature of this boat material.
This boat material was heat treated for 2 hours at a high temperature of 2000°C to create a boat for deposition. This boat is made up of long crystals with an L/W of 30, and the content of aluminum, silicon, and potassium is 0.005% by weight, respectively.
They were 0.003% by weight and 0.007% by weight. As a comparative example, a molybdenum evaporation boat with L/W of 1.3 was created. Using the thus obtained vapor deposition boat of the present invention and the boat of the comparative example, aluminum was vapor deposited and the lifespan was examined. As a result, the boat for vapor deposition of the present invention did not deform or crack even after being used 100 times, and there was no physical change due to molten aluminum. On the other hand, the comparative boat experienced physical changes due to molten aluminum after being used seven times.
Cracks appeared on the surface and it was no longer usable. As is clear from the above results, the vapor deposition boat of the present invention is less susceptible to molten aluminum and has a longer lifespan than conventional molybdenum boats. Examples 3 to 14 Three types of aluminum, silicon, and potassium were added to molybdenum powder in the form of a solution so that they could be uniformly mixed with the molybdenum powder, and when this was dried, the content of the added elements in the molybdenum powder was oxidized. Added 0.005% by weight, 0.005% by weight, and 0.01% by weight in the form of aluminum, silicon oxide, and potassium chloride, respectively;
Molybdenum powder with an average particle size of 2 to 5 μm was produced by reduction. This molybdenum powder, various powders having the composition shown in Table 1, and the molybdenum powder were mixed in a vibrating mill for 20 hours.

【table】

[Table] A sintered body was obtained from the obtained mixed powder in the same manner as in Example 1. This sintered body was hot-forged and hot-rolled in the same manner as in Example 2 to obtain a boat material. The processing rate of this boat material was 95%. Next, this boat material was heat-treated for 2 hours at a temperature of 2000° C., which is higher than the recrystallization temperature of the boat material, to create a boat for vapor deposition. Content and L/W when converted into aluminum, silicon, and potassium of this boat
were as shown in Table 2. As a comparative example, a molybdenum evaporation boat with L/W of 1.3 was created. Using the thus obtained vapor deposition boat of the present invention and the boat of the comparative example, aluminum was vapor deposited and the lifespan was investigated. The results are also shown in Table 2.

【table】

[Table] As is clear from the above results, the vapor deposition boat of the present invention is less susceptible to molten aluminum than conventional molybdenum, and has a long life. [Effects of the Invention] As described above, the molybdenum material using the present invention provides a molybdenum material with excellent oxidation resistance and long life.
Furthermore, it is possible to provide a molybdenum material that does not easily deteriorate with respect to molten aluminum.

Claims (1)

[Claims] 1. One or more compounds selected from aluminum, silicon, and potassium compounds, including aluminum,
The total amount converted to the amount of silicon and potassium,
A molybdenum material having excellent high-temperature strength and consisting of 0.005 to 0.75% by weight, the remainder being substantially molybdenum, and having long crystals at least on the surface. 2. The molybdenum material having excellent high-temperature strength according to claim 1, wherein the compound is one or more of oxides, chlorides, and silicotungstates. 3. A molybdenum material with excellent high-temperature strength as set forth in claim 1 for use in a furnace heater. 4. A molybdenum material with excellent high-temperature strength as set forth in claim 1 for use in an evaporation boat. 5. A molybdenum material with excellent high-temperature strength according to claim 1, which is used as a magnetron center support material. 6. A molybdenum material excellent in high-temperature strength as set forth in claim 1 and used as an anchor support material. 7. The molybdenum material excellent in high-temperature strength according to claim 1, wherein the ratio (L/W) between the maximum diameter (L) and the minimum diameter (W) of the long crystals is 10 or more. 8 One or more compounds selected from aluminum, silicon, and potassium compounds are combined with aluminum,
The total amount converted to the amount of silicon and potassium is 0.005
~0.75% by weight, one or more oxides, carbides, or nitrides of lanthanum, cerium, desprosium, yttrium, thorium, titanium, zirconium, niobium, tantalum, vanadium, chromium, or magnesium, 0.3 to 3% by weight in total %,
A molybdenum material having excellent high-temperature strength and having elongated crystals at least on the surface, with the remainder substantially consisting of molybdenum. 9. The molybdenum material having excellent high-temperature strength according to claim 8, wherein the compound is one or more of oxides, chlorides, and silicotungstates. 10 Claim 8 for use in furnace heater
A molybdenum material with excellent high-temperature strength as described in section. 11 Claim No. 8 used for vapor deposition boat
A molybdenum material with excellent high-temperature strength as described in section. 12. A molybdenum material with excellent high-temperature strength according to claim 8, which is used as a magnetron center support material. 13. A molybdenum material with excellent high-temperature strength according to claim 8, which is used as an anchor support material. 14 Claim 8 in which the ratio (L/) of the maximum diameter (L) to the minimum diameter (W) of the long and large crystal is 10 or more
A molybdenum material with excellent high-temperature strength as described in section.