JP2015140288A - Vessel for nitride crystal growth and method for manufacturing nitride crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vessel for nitride crystal growth capable of obtaining both heat and pressure resistance and corrosion resistance without lining or coating a material, such as a platinum group and noble metal.SOLUTION: The vessel for nitride crystal growth has a multiple structure consisting of a first nickel-chromium alloy on an outer wall side and a second nickel chromium alloy having higher corrosion resistance to a nitrogen containing solvent as compared with the first nickel-chromium alloy on an inner wall side. In such a multiple structure, the heat and pressure resistance of the vessel is guaranteed by the outer part consisting of the first nickel-chromium alloy, and the corrosion resistance of the vessel is guaranteed by the inner part consisting of the second nickel-chromium alloy. The second nickel chromium alloy preferably has a corrosion rate of 0.1 mm/year or less in a supercritical or subcritical nitrogen containing solvent.

Description

  The present invention relates to a vessel used for growing a nitride crystal and a method for producing a nitride crystal using the same, and more particularly, a nitride crystal is formed in the presence of a nitrogen-containing solvent in a supercritical state or a subcritical state. It relates to technology for growth.

  An ammonothermal method is known as one method for growing a nitride crystal in the presence of a nitrogen-containing solvent in a supercritical state or a subcritical state. In this method, a desired nitride crystal is produced by utilizing a dissolution-precipitation reaction of a nitride crystal raw material using an ammonia solvent in a supercritical state or a subcritical state.

  When growing a nitride crystal by the ammonothermal method, utilizing the temperature dependence of the solubility of the raw material in the ammonia solvent, a temperature difference is provided between the raw material in the reaction vessel and the seed crystal (seed), This temperature difference causes a supersaturated state in the vicinity of the seed crystal to cause crystal precipitation. Specifically, raw materials and seeds are placed in a reaction vessel such as an autoclave and sealed with a lid, etc., and heated with a heater installed inside or outside the reaction vessel to form a high temperature region and a low temperature region in the reactor. While the above raw material is dissolved in an ammonia solvent, a desired nitride crystal is produced by crystal precipitation on the seed.

  In order to obtain a high purity nitride crystal, it is necessary to bring a nitrogen-containing solvent such as ammonia into a supercritical state or a subcritical state. Therefore, the reaction vessel is required to have high pressure resistance at high temperatures. For this reason, the reaction container needs to be a container (pressure-resistant container) that can withstand high-temperature and high-pressure conditions such as a temperature of 600 ° C. or higher and a pressure of 200 MPa or higher.

  In addition, the nitrogen-containing solvent in a supercritical state or subcritical state under high temperature and high pressure exhibits extremely high corrosiveness, so that the reaction vessel has excellent corrosion resistance in addition to sufficient pressure resistance at high temperatures. It is required to be.

  Against this background, Patent Document 1 proposes a pressure vessel for growing a single crystal in which a pressure vessel body is made of a heat-resistant alloy and an inner surface thereof is subjected to corrosion-resistant mechanical lining. In this document, the material of the pressure vessel body is preferably a heat-resistant alloy of Fe-containing alloy, Ni-containing alloy, Cr-containing alloy, Mo-containing alloy, or Co-containing alloy. Corrosion-resistant mechanical lining is made of Pt, Ir , Rh and the like or alloys thereof are preferred.

  Further, in Patent Document 2, the pressure resistant container is preferably a Ni-based alloy or a Co-based alloy as a material excellent in corrosion resistance against an ammonia solvent among materials having high temperature strength and high corrosion resistance. In order to suppress internal corrosion of the pressure resistant container, it has been proposed to line or coat the inner surface of the container with a platinum group or a noble metal.

JP 2006-193355 A International Publication No. WO2012 / 090918

  However, when the inner surface of the container is lined with a platinum group or the like, since the strength of the platinum group or the like is weak, the lining of the platinum group or the like in a portion related to the lid may be damaged when the lid is opened or closed. In order to prevent the above damage, iridium etc. can be added to the part related to the lid to improve the strength, but in general, when trying to increase the size of the pressure resistant container, the lid is more in balance with the sealing property. Since it needs to be tightened strongly, there is a risk of cracking in the platinum group to which iridium or the like is added.

  Moreover, when enlarging a pressure-resistant container as mentioned above, since the intensity | strength of a platinum group etc. is weak, there exists a possibility that a platinum group etc. cannot be processed accurately. Furthermore, in the case of increasing the size of the pressure resistant container as described above, it is possible to achieve both heat resistance / pressure resistance and corrosion resistance without using an expensive material such as a platinum group in order to suppress the manufacturing cost. A reaction vessel is also required.

  Accordingly, the present inventors have intensively studied a reaction vessel that can achieve both heat resistance / pressure resistance and corrosion resistance without lining or coating a material such as a platinum group or a noble metal, thereby achieving the present invention. .

  In order to solve the above-mentioned problems, a nitride crystal growth vessel according to the present invention is a hermetic pressure-resistant vessel used for growth of nitride crystals, and the outer wall side of the vessel is a first nickel- It is made of a chromium alloy, and the inner wall side of the container is made of a second nickel-chromium alloy having higher corrosion resistance against a nitrogen-containing solvent than the first nickel-chromium alloy.

  Preferably, the second nickel-chromium alloy has a corrosion rate of 0.1 mm / year or less in a nitrogen-containing solvent in a supercritical state or a subcritical state.

  Preferably, in the second nickel-chromium alloy, the sum of the amount of δ phase, the amount of η phase, and the amount of Laves phase is 2% or less in the area ratio evaluation.

  Preferably, in the second nickel-chromium alloy, the sum of the amount of δ phase, amount of η phase, and amount of Laves phase after aging at 500 to 700 ° C. for 3000 hours is 10% or less in area ratio evaluation. is there.

  Preferably, the second nickel-chromium alloy has a tensile strength evaluated in a temperature range of 500 to 700 ° C. of 600 to 1300 MPa and an elongation at break of 5% or more.

Further, preferably, the second nickel-chromium alloy has a ratio of a restriction (R _H %) of a hydrogen charge material in which 50 to 60 ppm of hydrogen is charged to the alloy to a restriction (R ₀ %) of an uncharged material (R ₀ %). R _H / R ₀ ) is 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C.

  Preferably, the second nickel-chromium alloy has a nickel content of 50 to 80%, a chromium content of 15 to 30%, and an iron content of 5% or less by weight.

  Preferably, the first nickel-chromium alloy has a sum of δ phase amount, η phase amount, and Laves phase amount of 5% or less in area ratio evaluation.

  Preferably, in the first nickel-chromium alloy, the sum of the δ phase amount, the η phase amount, and the Laves phase amount after aging at 500 to 700 ° C. for 3000 hours is 10% or less in the area ratio evaluation. is there.

  Preferably, the first nickel-chromium alloy has a tensile strength evaluated in a temperature range of 500 to 700 ° C. of 700 to 1300 MPa and a breaking elongation of 5% or more.

Preferably, the first nickel-chromium alloy has a ratio (R _H %) of a hydrogen charging material ( ₅₀ % to 60 ppm of hydrogen) charged to the alloy (R ₀ %) of an uncharged material (R ₀ %). R _H / R ₀ ) is 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C.

  Preferably, the first nickel-chromium alloy has a nickel content of 20 to 70%, a chromium content of 10 to 25%, and an iron content of 40% or less by weight.

  Further, preferably, the thickness of the first nickel-chromium alloy layer on the outer wall side of the container is 60 mm or more.

  A nitride crystal growth container according to the present invention is a method for producing a nitride crystal using the above-described container, wherein the container is filled with a nitrogen-containing solvent, the container is sealed, and the container in the sealed container is A nitride crystal is grown with a nitrogen-containing solvent in a supercritical state or a subcritical state.

  Preferably, the nitride crystal is grown at a temperature of 600 ° C. or higher.

  Preferably, the nitride crystal is grown under a pressure of 200 MPa or more.

  Preferably, the nitrogen-containing solvent is ammonia.

  In the nitride crystal growth vessel according to the present invention, the outer wall is made of a first nickel-chromium alloy, and the inner wall is made of a second nickel having higher corrosion resistance to a nitrogen-containing solvent than the first nickel-chromium alloy. -It has a multiple structure consisting of a chromium alloy. In such a multiple structure, the heat resistance and pressure resistance of the container are ensured by the outer part made of the first nickel-chromium alloy, and the corrosion resistance of the container is ensured by the inner part made of the second nickel-chromium alloy.

  Therefore, the use of the above structure provides a reaction vessel that can achieve both heat resistance / pressure resistance and corrosion resistance without lining or coating a material such as a platinum group or a noble metal.

  In addition, by using the nitride crystal growth vessel according to the present invention, even when a nitride crystal is grown in a supercritical state or a subcritical state such as ammonia, the contamination of impurities from the vessel is suppressed. Thus, a high-quality nitride crystal can be obtained.

It is a schematic sectional drawing for demonstrating the structural example of the container for nitride crystal growth which concerns on this invention. It is a figure for demonstrating the corrosion weight loss (mg / cm < ² >) in the ammonia solvent (temperature 600 degreeC, pressure 200MPa) of each nickel-chromium alloy in a supercritical state. It is a figure for demonstrating the corrosion rate (mm / year) in the ammonia solvent (temperature 600 degreeC, pressure 200MPa) in the supercritical state of each nickel-chromium alloy. It is the SEM photograph which observed the structure before aging of Alloy718 (material A). It is the SEM photograph which observed the structure | tissue of Alloy718 (material A) after long-term aging of 10,000 hours at the temperature of 650 degreeC. Alloy 706 Mod. It is the SEM photograph which observed the structure before aging of (material B). Alloy 706 Mod. After prolonged aging for 5,000 hours at a temperature of 650 ° C. It is the SEM photograph which observed the organization of (material B). It is the SEM photograph which observed the structure before aging of Alloy625 (material D). It is the SEM photograph which observed the structure | tissue of Alloy625 (material D) after 3,000 hours of long-time aging at the temperature of 650 degreeC. Alloy 718 (Material A), Alloy 706 Mod. It is the figure which compared and showed the result of having investigated the tensile strength about (material B), Rene41 (material C), and Alloy625 (material D). Alloy 718 (Material A), Alloy 706 Mod. It is the figure which compared and showed the result of having investigated breaking elongation about (material B), Rene41 (material C), and Alloy625 (material D). Alloy 718 (Material A), Alloy 706 Mod. Ratio (R _H / R ₀ ) of the hydrogen charged material restriction (R _H %) and the uncharged material restriction (R ₀ %) for (Material B), Rene 41 (Material C), and Alloy 625 (Material D) It is the figure which showed the result of having investigated and compared. It is a block diagram which shows the 1st structural example of the crystal growth apparatus by the ammonothermal method using the container for nitride crystal growth of this invention. It is a block diagram which shows the 2nd structural example of the crystal growth apparatus by the ammonothermal method using the container for nitride crystal growth of this invention.

  A nitride crystal growth vessel according to the present invention and a method for producing a nitride crystal using the same will be described below with reference to the drawings. In addition, the aspect demonstrated below is only the illustration for implementing this invention, and this invention is not limited to these embodiment. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Basic structure of nitride crystal growth vessel]
FIG. 1 is a schematic cross-sectional view for explaining a structural example of a nitride crystal growth vessel according to the present invention. The term “nitride crystal growth vessel” as used in the present specification refers to containing the nitrogen-containing solvent when growing a nitride crystal in the presence of a nitrogen-containing solvent in a supercritical state or a subcritical state. The inner wall surface of the container is in contact with a nitrogen-containing solvent in a supercritical state or a subcritical state.

  As shown in FIG. 1, the container 10 for growing a nitride crystal is different in a container inner wall side 2 and a container outer wall side 1 in which a nitrogen-containing solvent in a supercritical state or a subcritical state is in direct contact. It has a multiple structure made of materials. During the growth of the nitride crystal, the opening at the top of the container 10 shown in FIG. 1 is closed with a lid member having a multiple structure similar to that of the container 10, and the inside of the container 10 is sealed.

  Both the outer wall side 1 and the inner wall side 2 of the container 10 are made of a nickel-chromium alloy, but the alloy composition is different, and the material of the inner wall side 2 is compared to the first nickel-chromium alloy on the outer wall side 1. Thus, the second nickel-chromium alloy having high corrosion resistance against the nitrogen-containing solvent is selected.

  The heat resistance and pressure resistance of such a multi-structure container 10 is ensured mainly by the outer wall side 1 made of the first nickel-chromium alloy, and the corrosion resistance of the container 10 is made by the inner wall side 2 made of the second nickel-chromium alloy. Secured by In that sense, the portion on the outer wall side 1 made of the first nickel-chromium alloy is the “pressure-resistant portion” (P), and the portion on the inner wall side 2 made of the second nickel-chromium alloy is the “corrosion-resistant portion” (C). Can also be called.

  Here, the “pressure-resistant portion” (P) on the outer wall side 1 made of the first nickel-chromium alloy and the “corrosion-resistant portion” (C) on the inner wall side 2 made of the second nickel-chromium alloy were integrated. Although it is good also as a thing, both can be divided | segmented and it is good also as a thing of the aspect which inserts and uses the corrosion-resistant part C inside the pressure-resistant part P.

  In FIG. 1, the container 10 is shown as having a double structure composed of the pressure-resistant portion P and the corrosion-resistant portion C. However, the first and second nickels are interposed between the pressure-resistant portion P and the corrosion-resistant portion C. -It is good also as a thing of the structure which provided the part which consists of a material different from a chromium alloy.

  Furthermore, in order to sufficiently ensure the strength of the pressure-resistant portion P, the thickness of the first nickel-chromium alloy layer on the outer wall side of the container is preferably 60 mm or more, and more preferably 100 mm or more. .

  That is, the nitride crystal growth vessel according to the present invention is a hermetic pressure-resistant vessel used for nitride crystal growth, and the outer wall side of the vessel is made of the first nickel-chromium alloy, and the inner wall of the vessel The side has at least a double structure consisting of a second nickel-chromium alloy that is more resistant to corrosion by nitrogen-containing solvents than the first nickel-chromium alloy.

  These first and second nickel-chromium alloys are selected so that they can withstand high-temperature and high-pressure conditions when growing nitride crystals by the ammonothermal method. Is selected from those having high corrosion resistance to a nitrogen-containing solvent such as ammonia in a supercritical state or a subcritical state.

  In the present invention, a material having the following characteristics is selected as a preferred material for the second nickel-chromium alloy.

  From the viewpoint of high corrosion resistance to the nitrogen-containing solvent required for the second nickel-chromium alloy, the corrosion rate in the nitrogen-containing solvent in the supercritical state or subcritical state is 0.1 mm / year or less. preferable.

  In addition, from the viewpoint of heat resistance and pressure resistance required for the second nickel-chromium alloy, the embrittlement phase precipitated in the pre-aging alloy is the sum of the δ phase amount, η phase amount, and Laves phase amount. However, it is preferable that it is 2% or less by area ratio evaluation.

  Further, in the second nickel-chromium alloy, the sum of the δ phase amount, the η phase amount, and the Laves phase amount after aging at 500 to 700 ° C. for 3000 hours is preferably 10% or less in the area ratio evaluation. .

  The second nickel-chromium alloy preferably has a tensile strength of 600 to 1300 MPa evaluated in a temperature range of 500 to 700 ° C. and an elongation at break of 5% or more.

Furthermore, the second nickel-chromium alloy has a ratio (R _H / R) of the restriction (R _H %) of the hydrogen charge material charged with 50 to 60 ppm of hydrogen to the restriction (R ₀ %) of the uncharged material. ₀ ) is preferably 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C.

  A desirable composition of such a second nickel-chromium alloy is 50 to 80% nickel content, 15 to 30% chromium content, and 5% or less iron content by weight ratio.

  Examples of the second nickel-chromium alloy used in the present invention include Rene 41, Alloy 230, and Alloy 625.

  In the present invention, the first nickel-chromium alloy having the following characteristics is selected as a preferable material.

  From the viewpoint of heat resistance and pressure resistance required for the first nickel-chromium alloy, the embrittlement phase precipitated in the pre-aging alloy has a total amount of δ phase amount, η phase amount, and Laves phase amount, It is preferable that it is 5% or less by area ratio evaluation.

  In the first nickel-chromium alloy, the sum of the δ phase amount, the η phase amount, and the Laves phase amount after aging at 500 to 700 ° C. for 3000 hours is preferably 10% or less in the area ratio evaluation. .

  Furthermore, it is preferable that the first nickel-chromium alloy has a tensile strength of 700 to 1300 MPa evaluated in a temperature range of 500 to 700 ° C. and an elongation at break of 5% or more.

Further, the first nickel-chromium alloy has a ratio (R _H / R) of the restriction (R _H %) of the hydrogen charge material in which 50 to 60 ppm of hydrogen is charged to the alloy and the restriction (R ₀ %) of the uncharged material. ₀ ) is preferably 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C.

  A desirable composition of such a first nickel-chromium alloy is, by weight ratio, a nickel content of 20 to 70%, a chromium content of 10 to 25%, and an iron content of 40% or less.

  Examples of the first nickel-chromium alloy used in the present invention include Alloy 706 Mod. , Alloy 718.

  The thickness of the pressure-resistant portion P made of the first nickel-chromium alloy is preferably 60 mm or more, and particularly preferably 100 mm or more in order to ensure sufficient pressure resistance.

  Hereinafter, the reason why the above-mentioned characteristics are determined to be preferable as the first and second nickel-chromium alloys will be described.

[Results of corrosion test of nickel-chromium alloy]
Nickel-chromium alloy samples having different compositions were prepared, and the corrosion rate in an ammonia solvent in a supercritical state was examined for each alloy.

  The nickel-chromium alloy used for the evaluation is Alloy 718 (Material A), Alloy 706 Mod. (Material B), Rene 41 (Material C), Alloy 625 (Material D), and Alloy 625 HAZ (Material E) which is a heat affected zone of the Alloy 625 (Heat Affected Zone).

  Table 1 shows the composition (weight ratio: mass%) of the nickel-chromium alloy.

  Note that Alloy 706 Mod. Is the sum of the addition amounts of Al (0.2 mass%) and Nb (3 mass%) in Alloy 706, and the addition amount of Al is 1.2 mass%. Moreover, since Alloy 625 (material D) and Alloy 625HAZ (material E) are the same material, the composition does not change.

  The corrosion weight loss of these nickel-chromium alloys in a supercritical ammonia solvent (temperature 600 ° C., pressure 200 MPa) was investigated up to 3000 hours to determine the corrosion rate. In this test, in order to investigate the corrosion resistance under standard conditions when growing gallium nitride crystals by the ammonothermal method, the above-mentioned nickel-chromium alloy sample is placed in the pressure vessel actually used for crystal growth. However, no mineralizer was added to the ammonia solvent.

2A and 2B are diagrams for explaining the total corrosion weight loss (mg / cm ² ) and corrosion rate (mm / year) of each nickel-chromium alloy, respectively.

  None of Rene 41 (material C), Alloy 625 (material D), and Alloy 625 HAZ (material E) show any significant corrosion weight loss even after 3000 hours in the ammonia solvent in the supercritical state. The speed was 0.1 mm / year or less, and it was revealed that the film exhibited high corrosion resistance against nitrogen-containing solvents. In addition, it was recognized that Alloy 625 (Material D) and Alloy 625 HAZ (Material E) do not change the corrosion resistance. That is, it was recognized that the corrosion resistance did not change even when Alloy 625 (material D) was welded.

  Compared to these nickel-chromium alloys, Alloy 718 (Material A) and Alloy 706 Mod. (Material B) has a significant weight loss due to corrosion, the corrosion rate exceeds 0.1 mm / year, and is unsuitable for use as the corrosion resistant part C of the nitride crystal growth container according to the present invention. Conceivable.

  All of the nickel-chromium alloys exhibiting high corrosion resistance with a corrosion rate of 0.1 mm / year or less in the above corrosion test have a nickel content of 50 to 80%, a chromium content of 15 to 30%, and an iron content of 5%. A nickel-chromium alloy having the following composition may be selected as the nickel-chromium alloy used in the corrosion-resistant portion C of the nitride crystal growth vessel.

  Alloy 230, which is known as an alloy exhibiting high-temperature oxidation resistance and excellent in high-temperature strength, has a weight ratio of nickel content of 57%, chromium content of 22%, and iron content of about 3%. Moreover, it may be considered that it is a nickel-chromium alloy suitable for use as the corrosion resistant part C of the nitride crystal growth vessel according to the present invention.

[Precipitation test result of embrittlement phase of nickel-chromium alloy]
As is well known, the precipitation of an embrittled phase in a metal material reduces the strength and toughness of the material. Since the nickel-chromium alloy used in the nitride crystal growth vessel of the present invention needs to maintain sufficient strength and toughness even when used at high temperature and high pressure, such a brittle phase precipitates. It must be difficult. Therefore, the degree of precipitation of the embrittlement phase was investigated for various nickel-chromium alloys under the same environment as the actual nitride crystal growth conditions.

  3A, FIG. 4A, and FIG. 5A show the above-mentioned Alloy 718 (Material A), Alloy 706 Mod. It is a SEM photograph which observed the structure before aging of (material B) and Alloy625 (material D). While precipitation of δ phase is observed in a part of Alloy 718 (Material A), Alloy 706 Mod. In (Material B), no precipitation of the embrittlement phase is observed. In Alloy 625 (material D), almost no precipitation of embrittlement phases such as δ phase, η phase, and Laves phase is observed.

  When the content of the embrittled phase of the nickel-chromium alloys of materials A to E before aging was examined, Alloy 718 (Material A) and Alloy 706 Mod. (Material B) has a total content of δ phase, η phase, and Laves phase, which are embrittled phases, of 5% or less in area ratio evaluation, Rene 41 (Material C), Alloy 625 (Material D), And about Alloy625HAZ (material E), the sum total of the said (delta) phase amount, (eta) phase amount, and Laves phase amount was 2% or less by area ratio evaluation.

  In order to investigate the degree of precipitation of the embrittlement phase of these nickel-chromium alloys under the same environment as the actual nitride crystal growth conditions, the alloy was aged at 500 to 700 ° C. for a long time. The degree of precipitation was investigated.

  FIG. 3B is a SEM photograph observing the structure of Alloy 718 (material A) after long-term aging at 10,000 ° C. for 650 ° C. In the material A after aging for a long time, an increase in the δ phase at the grain boundary is observed, but no precipitation of the embrittlement phase within the grain is observed, and the required strength and dust are also obtained at high temperature and high pressure. Sex is generally maintained.

  FIG. 4B shows Alloy 706 Mod. After prolonged aging for 5,000 hours at a temperature of 650 ° C. It is the SEM photograph which observed the organization of (material B). Even in the material B after aging for a long time, although an increase in the δ phase at the grain boundary is recognized, no precipitation of the embrittlement phase is observed in the grains, and similarly to the material A, even at high temperature and high pressure, The required strength and toughness are generally maintained.

  FIG. 5B is an SEM photograph observing the structure of Alloy 625 (material D) after aging for 3,000 hours at a temperature of 650 ° C., and precipitation of δ phase is observed at the grain boundaries. Also in the material D, the required strength and toughness are generally maintained.

  The contents of the embrittled phase after aging of the above-described nickel-chromium alloys of materials A to E were examined. As a result, the amount of δ phase, the amount of η phase after aging at 500 to 700 ° C. for 3000 hours, and Laves The sum of the phase amounts was 10% or less in the area ratio evaluation.

  Nickel-chromium alloys A and B have a nickel content of 20 to 70%, a chromium content of 10 to 25%, an iron content of 40% or less, and a corrosion rate of 0.1 mm / year or less in a corrosion test. The nickel-chromium alloys C to E exhibiting high corrosion resistance are all of a composition having a nickel content of 50 to 80%, a chromium content of 15 to 30%, and an iron content of 5% or less. , As described above.

[Tensile strength test result of nickel-chromium alloy]
FIGS. 6 and 7 show, respectively, Alloy 718 (Material A), Alloy 706 Mod. It is the figure which compared and showed the result of having investigated the tensile strength (FIG. 6) and breaking elongation (FIG. 7) about (material B), Rene41 (material C), and Alloy625 (material D). 6 to 7 show the test results at a temperature of 625 ° C. Since Alloy 625 (Material D) and Alloy 625 HAZ (Material E) are the same material and have the same mechanical properties, the result of Alloy 625 HAZ (Material E) is the same as that of Alloy 625 (Material D). is there.

  All of these nickel-chromium alloys have a tensile strength of approximately 900 to 1300 MPa and an elongation at break of approximately 10 to 30% at a temperature of 625 ° C.

  From these experimental results, Alloy 718 (Material A) and Alloy 706 Mod. As for (Material B), it is estimated that the tensile strength is 700 to 1300 MPa and the elongation at break is 5% or more in a temperature range of at least 500 to 700 ° C. Further, with respect to Rene 41 (material C), Alloy 625 (material D), and Alloy 625 HAZ (material E), the tensile strength is 600 to 1300 MPa and the elongation at break is 5% in a temperature range of at least 500 to 700 ° C. It is estimated that this is the case.

[Hydrogen charge tensile test results of nickel-chromium alloy]
FIG. 8 shows Alloy 718 (Material A), Alloy 706 Mod. It is the figure which compared and showed the result of having investigated the tensile strength of the hydrogen charge material about (material B), Rene41 (material C), and Alloy625 (material D). Here, the tensile strength is defined as the ratio (R _H / R ₀ ) between the drawing (R _H %) of the alloy charged with 50 to 60 ppm of hydrogen (hydrogen charging material) and the drawing (R ₀ %) of the uncharged material. ) At a temperature of 625 ° C.

In any nickel-chromium alloy, the drawing ratio (R _H / R ₀ ) is in the range of 0.35 to 1.0 at a temperature of 625 ° C.

From these experimental results, in the temperature range of at least 500 to 700 ° C., each of the materials A to E described above has a drawing ratio (R _H / R ₀ ) of 0.3 or more at a hydrogen charge amount of 50 to 60 ppm. It is estimated to show the value of.

[Nickel-chromium alloy preferably selected in the present invention]
According to the results of the above-described various characteristic evaluations, the first nickel-chromium alloy as the pressure-resistant part P, which is preferably selected in the present invention, can be arranged as follows.

  The sum of the amount of δ phase, the amount of η phase, and the amount of Laves phase is 5% or less in the area ratio evaluation.

  The sum of the amount of δ phase, amount of η phase, and amount of Laves phase after aging at 500 to 700 ° C. for 3000 hours is 10% or less by area ratio evaluation.

  The tensile strength evaluated in the temperature range of 500-700 degreeC is 700-1300 Mpa, and elongation at break is 5% or more.

The ratio (R _H / R ₀ ) of the hydrogen charged material (R _H %) charged with 50-60 ppm of hydrogen in the alloy to the uncharged material (R ₀ %) is 500 to 700 ° C. in the temperature range. It is 0.3 or more in the tensile test.

  The nickel content is 20 to 70%, the chromium content is 10 to 25%, and the iron content is 40% or less by weight.

  Moreover, the 2nd nickel-chromium alloy as the corrosion-resistant part C preferably selected by this invention can be arranged as follows.

  The corrosion rate in a nitrogen-containing solvent in a supercritical state or a subcritical state is 0.1 mm / year or less.

  The sum of the amount of δ phase, the amount of η phase, and the amount of Laves phase is 2% or less in the area ratio evaluation.

  The sum of the amount of δ phase, amount of η phase, and amount of Laves phase after aging at 500 to 700 ° C. for 3000 hours is 10% or less by area ratio evaluation.

  The tensile strength evaluated in the temperature range of 500-700 degreeC is 600-1300 MPa, and elongation at break is 5% or more.

The ratio (R _H / R ₀ ) of the hydrogen charged material (R _H %) charged with 50-60 ppm of hydrogen in the alloy to the uncharged material (R ₀ %) is 500 to 700 ° C. in the temperature range. It is 0.3 or more in the tensile test.

  The nickel content is 50 to 80%, the chromium content is 15 to 30%, and the iron content is 5% or less by weight.

[Configuration Example of Crystal Growth Apparatus Using Nitride Crystal Growth Vessel of the Present Invention]
FIG. 9 is a block diagram showing a first configuration example of an ammonothermal crystal growth apparatus using the above-described nitride crystal growth vessel.

  The inside of the container 10 is divided into two parts by a baffle material 3, the lower side is a raw material dissolution region for dissolving the raw material 4 in ammonia, and the upper side is a crystal for growing a nitride crystal loaded with a seed crystal 5. It becomes a growth area.

  The upper part of the container 10 is sealed with a lid 6, and is heated by a heater (not shown) installed on the outside during crystal growth. The lid 6 is provided with a conduit 7 through which a vacuum pump 11, an ammonia cylinder 12 and a nitrogen cylinder 13 are attached through a valve 8. The ammonia cylinder 12 is provided with a mass flow meter 14.

  In addition, in order to adjust the pressure of the container 10, the container 10 used for this invention may have at least 1 or more valve | bulb. The number of valves is not particularly limited, but it is preferable to have two or more valves in order to perform pressure regulation safely and effectively. Further, the position where the valve is arranged is not particularly limited, and a plurality of valves may be arranged in series or may be arranged in parallel. It is preferable that at least two valves are arranged in series because the pressure adjustment can be performed safely and effectively.

  FIG. 10 is a block diagram showing a second configuration example of an ammonothermal crystal growth apparatus using the above-described nitride crystal growth vessel.

  An inner cylinder 20 of, for example, a platinum group is inserted and installed in the container 10, and the baffle material 3, the raw material 4, and the seed crystal 5 are set in the inner cylinder 20.

  In the case of growing a nitride crystal by the ammonothermal method using the apparatus having the configuration shown in FIG. 9, first, the raw material 4, the seed crystal 5, and a solvent containing nitrogen are put in a container 10 and sealed. Stop. Prior to introducing these into the container 10, the inside of the container 10 may be deaerated. Moreover, you may distribute | circulate inert gas, such as nitrogen gas, at the time of these introduction | transduction. The seed crystal 5 is normally charged into the container 10 at the same time as or after the raw material 4 is filled. After loading these, the container 10 may be heated and degassed as necessary.

  When the apparatus having the configuration shown in FIG. 10 is used, the inner cylinder 20 is sealed with the raw material 4, the seed crystal 5, and a nitrogen-containing solvent, and further the inner wall and inner cylinder of the container 10. The solvent is also put into the gap between the outer wall 20 and an appropriate spacer or the like is installed if necessary, and then the whole is sealed.

  Note that the solvent in the gap between the inner wall of the container 10 and the outer wall of the inner cylinder 20 does not necessarily need to be a nitrogen-containing solvent used for crystal growth. However, since these solvents are practically placed under an environment of the same pressure and the same temperature, those having the same physical properties as the solvent inside the inner cylinder 20 are preferable. In that sense, the solvent in the gap between the inner wall of the container 10 and the outer wall of the inner cylinder 20 is normally a nitrogen-containing solvent used for crystal growth.

  The nitrogen-containing solvent used in the ammonothermal method is preferably one that does not impair the stability of the nitride single crystal to be grown. Examples include ammonia, hydrazine, urea, amines (primary amines such as methylamine, secondary amines such as dimethylamine, tertiary amines such as trimethylamine, and ethylenediamine. Diamines), melamine and the like. These solvents may be used alone or in combination. Among these, it is preferable to use ammonia.

  The amount of water and oxygen contained in the solvent is desirably as small as possible, and the content thereof is preferably 1000 ppm or less, more preferably 10 ppm or less, and further preferably 0.1 ppm or less. When ammonia is used as a solvent, the purity is usually 99.9% or more, preferably 99.99% or more, more preferably 99.999% or more, and particularly preferably 99.9999% or more. .

  In the manufacturing method of the present invention, a raw material containing an element constituting the nitride crystal to be grown is used. For example, when producing a Group III nitride crystal, a Group III nitride polycrystal is used as a raw material, and a Group III element metal is added as necessary. When manufacturing a gallium nitride crystal, a gallium nitride polycrystal is used as a raw material, and gallium metal is added as necessary. Note that the polycrystalline raw material does not need to be a complete nitride, and may contain a metal component in which the group III element is in a metal state (zero valence) depending on conditions. For example, the crystal is gallium nitride. In some cases, a mixture of gallium nitride and metal gallium is included.

  The method for producing the polycrystalline raw material is not particularly limited. For example, a nitride polycrystal produced by reacting a metal or an oxide or hydroxide thereof with ammonia in a reaction vessel in which ammonia gas is circulated can be used. In addition, as a metal compound raw material having higher reactivity, a compound having a covalent MN bond (metal-nitrogen bond) such as a halide, an amide compound, an imide compound, or galazan can be used. Furthermore, a nitride polycrystal produced by reacting a metal such as Ga with nitrogen at a high temperature and a high pressure can also be used.

  The amount of water and oxygen contained in the polycrystalline raw material used as the raw material in the present invention is preferably small. The oxygen content in the polycrystalline raw material is usually 10,000 ppm or less, preferably 1000 ppm or less, particularly preferably 1 ppm or less. The ease of mixing oxygen into the polycrystalline raw material is related to the reactivity with water or the absorption capacity. The worse the crystallinity of the polycrystalline raw material, the more active groups such as NH groups exist on the surface, which may react with water and partially generate oxides or hydroxides. For this reason, it is usually preferable to use a polycrystalline material having as high crystallinity as possible. The crystallinity can be estimated by the half width of powder X-ray diffraction. The half width of the (100) diffraction line (2θ = about 32.5 ° for hexagonal gallium nitride) is usually 0.25 ° or less, preferably It is 0.20 ° or less, more preferably 0.17 ° or less.

  After the filling preparation into the container 10 is completed, the whole is heated to bring the nitrogen-containing solvent in the container 10 into a supercritical state or a subcritical state. In the supercritical state, the viscosity is generally low and it is more easily diffused than the liquid, but has the same solvating power as the liquid. The subcritical state means a liquid state having a density substantially equal to the critical density near the critical temperature. For example, in the raw material melting region, the raw material is melted as a supercritical state, and in the crystal growth region, the temperature is changed so as to be in the subcritical state, and crystal growth using the difference in solubility between the supercritical state and the subcritical state raw material is also performed. Is possible.

  When in the supercritical state, the reaction mixture is generally maintained at a temperature above the critical point of the solvent. When ammonia is used as a solvent, the critical point is a critical temperature of 132 ° C. and a critical pressure of 11.35 MPa. If the filling rate with respect to the volume of the container 10 is high, the pressure far exceeds the critical pressure even at a temperature below the critical temperature. . In the present invention, the “supercritical state” includes such a state exceeding the critical pressure. Since the reaction mixture is enclosed in a constant volume reaction vessel, the increase in temperature increases the pressure of the fluid. In general, if T> Tc (critical temperature of one solvent) and P> Pc (critical pressure of one solvent), the fluid is in a supercritical state.

  Under supercritical conditions, a sufficient growth rate of nitride crystals can be obtained. The reaction time depends on the temperature and pressure values. During the synthesis or growth of the nitride crystal, the pressure in the reaction vessel is preferably 120 MPa or more, more preferably 150 MPa or more, and further preferably 180 MPa or more. The pressure in the container 10 is preferably 700 MPa or less, more preferably 300 MPa or less, further preferably 280 MPa or less, and particularly preferably 250 MPa or less. The pressure is appropriately determined depending on the temperature and the filling rate of the solvent volume with respect to the volume of the container 10. Originally, the pressure in the container 10 is uniquely determined by the temperature and the filling rate. However, in reality, the pressure in the container 10 may vary depending on additives such as raw materials, temperature non-uniformity in the container 10, and the presence of free volume. Different.

  The lower limit of the temperature range in the container 10 is preferably 500 ° C or higher, more preferably 515 ° C or higher, and further preferably 530 ° C or higher. The upper limit value is preferably 700 ° C. or lower, more preferably 650 ° C. or lower, and further preferably 630 ° C. or lower.

  In the method for producing a nitride crystal of the present invention, the temperature of the raw material melting region in the reaction vessel is preferably higher than the temperature of the crystal growth region. The temperature difference (| ΔT |) between the raw material melting region and the crystal growth region is preferably 5 ° C. or higher, and more preferably 10 ° C. or higher, from the viewpoint of maintaining crystal quality and controlling spontaneous nucleation crystals. Preferably, it is 100 ° C. or less, more preferably 80 ° C. or less, and particularly preferably 60 ° C. or less. The optimum temperature and pressure in the reaction vessel can be appropriately determined according to various conditions during crystal growth.

  The injection ratio of the solvent into the container 10 to achieve the temperature range and pressure range in the container 10, that is, the filling rate is usually 20 to 95 based on the liquid density at the boiling point of the free volume of solvent in the container 10. %, Preferably 30 to 80%, more preferably 40 to 70%. Here, when the polycrystalline raw material, the seed crystal, and the baffle plate are introduced into the container 10, the above “free volume” refers to the volume thereof (and the volume of the accessory used for installing them), The remaining volume is subtracted from the volume of the container 10.

  The growth of the nitride crystal in the vessel 10 is performed by heating the vessel 10 from the outside using an electric furnace having a thermocouple, and keeping the vessel 10 in a subcritical or supercritical state of a solvent such as ammonia. Is done. The heating method and the rate of temperature increase to a predetermined reaction temperature are not particularly limited, but are usually performed over several hours to several days. If necessary, the temperature can be raised in multiple stages, or the rate of temperature rise can be adjusted in the temperature range. It can also be heated while being partially cooled.

  The “reaction temperature” can be measured by a thermocouple provided so as to be in contact with the outer wall of the container 10 or a thermocouple inserted into a hole having a certain depth from the outer wall surface. Based on this, the internal temperature of the container 10 can also be estimated. Usually, the average value of the temperatures measured with these thermocouples is taken as the average temperature.

  The reaction time after reaching a predetermined temperature depends on the type of nitride crystal, the raw material used, the size and amount of the crystal to be produced, and can usually be several hours to several hundred days. . During the crystal growth, the reaction temperature may be constant or may be gradually raised or lowered. After a reaction time for generating a desired crystal, the nitride crystal grown in the container 10 is taken out by lowering the temperature. The method for lowering the temperature is not particularly limited, but the heating of the heater may be stopped and the reaction vessel may be allowed to cool as it is in the furnace, or the reaction vessel may be removed from the electric furnace and air cooled. If necessary, quenching with a refrigerant is also preferably used.

  After the outer wall temperature of the container 10 or the estimated internal temperature of the container 10 falls below a predetermined temperature, the reaction container is opened. The predetermined temperature at this time is not particularly limited, and is usually −80 ° C. to 200 ° C., preferably −33 ° C. to 100 ° C. Here, piping may be connected to the piping connection port of the valve attached to the container 10, and the valve may be opened by passing through a container filled with water or the like. Further, if necessary, the ammonia solvent in the container 10 is sufficiently removed by making a vacuum or the like, and then dried, the nitride crystal grown by opening the lid 6 of the container 10 and the unreacted raw material, etc. Can be taken out.

  In addition, when manufacturing a gallium nitride according to the manufacturing method of the nitride crystal of this invention, Unexamined-Japanese-Patent No. 2009-263229 can be referred preferably for details, such as conditions other than the above. The entire disclosure of this document is incorporated herein by reference.

  The type of nitride crystal produced by the production method of the present invention is not particularly limited. For example, group III nitride crystals are preferable, and gallium nitride, aluminum nitride, indium nitride, mixed crystals thereof, and the like are more preferable.

  Thus, in the method for producing a nitride crystal according to the present invention, the container 10 according to the present invention described above is used, the container 10 is filled with a nitrogen-containing solvent, the container 10 is sealed, and the sealed container 10 is sealed. The nitride crystal is grown in a supercritical state or subcritical state.

  The growth of the nitride crystal is preferably performed at a temperature of 600 ° C. or higher.

  The growth of the nitride crystal is preferably performed under a pressure of 200 MPa or more.

  Further preferably, the nitrogen-containing solvent is ammonia.

  In the following examples, the nitride crystal produced according to the present invention will be described using gallium nitride (GaN) as an example, but the production method of the present invention is not limited to this. In addition, the conditions and the like shown in the following examples are merely examples, and can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

In this example, GaN crystal growth was performed using the apparatus having the configuration shown in FIG. Using a container 10 having an inner dimension of 150 mm in diameter and a length of 1800 mm (inner volume of about 33,300 cm ³ ) as the container 10, a capsule made of Pt-Ir 10% (TS (Tensile Strength) = 382 MPa) having an inner diameter of 128 mm and a wall thickness of 1.0 mm. A GaN crystal was grown using the inner cylinder 20 as a reaction vessel.

  The pressure-resistant part P of the container 10 is made of the above-described Alloy 718 (material A) and has a thickness of 104.5 mm. Further, the corrosion resistant part C of the container 10 is made of the above-described Alloy 625 (material D).

  The inner surface of the container 10 and the inner surface of the inner cylinder 20 were sufficiently washed and dried. The platinum wire used for supporting the test piece, the platinum baffle plate 3 and the like were similarly washed and dried.

Polycrystalline GaN particles were used as the raw material 4 for growing nitride crystals, and were placed in the lower region of the inner cylinder 20, and high-purity NH ₄ I and GaF ₃ were charged into the inner cylinder 20 as mineralizers.

Next, a platinum baffle plate 3 was installed at a position that substantially bisects the raw material dissolution region at the bottom of the inner cylinder 20 and the crystal growth region at the top. As a seed crystal, a wafer having an M surface grown by the HVPE method as a main surface was used. This seed crystal was hung on a platinum seed crystal support frame by a platinum wire and installed in the crystal growth region at the upper part of the inner cylinder 20. The free volume in the inner cylinder 20 after arranging the raw material 4, the mineralizer, the baffle plate 3, the seed crystal 5, the seed crystal support frame, and the like was 18835 cm ³ .

Next, a valve was connected to a tube attached to the inner cylinder 20, and after vacuum deaeration through a vacuum pump, the inner cylinder 20 was repeatedly purged with nitrogen gas by operating so as to communicate with a nitrogen cylinder. Then, it deaerated by heating in the state connected to the vacuum pump. After naturally cooling the inner cylinder 20 to room temperature, the valve was closed and the capsule was cooled with a dry ice ethanol solvent while maintaining the vacuum state. Then, after operating the valve of the conduit so as to pass through the NH ₃ cylinder, the valve is opened again, and NH ₃ is filled as a liquid corresponding to about 53% of the free volume of the inner cylinder 20 based on the flow rate control without touching the outside air. (Converted to NH ₃ density at −33 ° C.), the valve was closed again. The filling amount was confirmed from the difference in weight before and after filling NH ₃ .

Next, after inserting the inner cylinder 20 into the container 10 equipped with the valve 8, the lid was closed and the weight of the container 10 was measured. The free volume in the container 10 after the inner cylinder 20 was installed was 10474 cm ³ .

  Next, the conduit 7 was operated to pass through the valve 8 to the vacuum pump 11, and the valve 8 was opened to evacuate the inside of the container 10. After performing nitrogen gas purging a plurality of times in the same manner as the inner cylinder 20, the container 10 was cooled with dry ice methanol solvent while maintaining the vacuum state, and the valve 8 was once closed.

Next, after the conduit 7 is operated so as to communicate with the ammonia cylinder 12, the valve 8 is opened again, and NH ₃ corresponds to about 53% of the free volume of the inner cylinder 20 based on the flow rate control without continuously touching the outside air. After filling the container 10 with ammonia as a liquid (in terms of NH ₃ density at −33 ° C.), the valve was closed again.

  Then, the container 10 was accommodated in the electric furnace comprised with the heater divided into 2 up and down. After raising the temperature over 12 hours, setting the outer wall temperature of the container 10 so that the outer surface temperature of the lower part of the container 10 is 625 ° C. and the outer surface temperature of the upper part of the container 10 is 605 ° C. Hold for 30 days.

In addition, about the relationship between the outer wall temperature of the container 10 and the internal solvent temperature of the container 10, the correlation formula based on measurement is created beforehand. Based on this correlation equation, the solvent temperature in the inner cylinder 20 was calculated to be 601 ° C. at the lower part of the inner cylinder 20 and 595 ° C. at the upper part.
The pressure in the container 10 was about 210 MPa. Further, the variation in the control temperature during the temperature holding was ± 0.3 ° C. or less. No steep changes in pressure during the temperature raising period and the growth period were observed, suggesting that the operation was terminated without breaking both the container 10 and the inner cylinder 20.

  After the completion of heating, the temperature was lowered in about 24 hours using a program controller until the temperature of the lower outer surface of the container 10 reached 150 ° C., then the heating by the heater was stopped and the mixture was naturally cooled in an electric furnace. After confirming that the temperature of the lower outer surface of the container 10 had dropped to approximately room temperature, first, the valve attached to the container 10 was opened, and ammonia in the container 10 was removed.

  Next, the ammonia in the container 10 was completely removed with a vacuum pump. Thereafter, the lid 6 of the container 10 was opened, the inner cylinder 20 was taken out, and the GaN crystal was taken out from the inside of the inner cylinder 20. The obtained crystal was confirmed to be a high-quality single crystal with high transparency and low impurity content. Moreover, the contamination from the nickel-chromium alloy which is the material of the container 10 was not confirmed.

  Furthermore, although the container 10 was confirmed in detail, neither the pressure-resistant part P made of Alloy 718 nor the corrosion-resistant part C made of Alloy 625 showed any noticeable deterioration, deformation, or the like. It was confirmed that the heat resistance and pressure resistance were ensured and that the corrosion resistance of the container 10 was ensured by selecting Alloy 625.

  In the nitride crystal growth vessel according to the present invention, the outer wall is made of a first nickel-chromium alloy, and the inner wall is made of a second nickel having higher corrosion resistance to a nitrogen-containing solvent than the first nickel-chromium alloy. -It has a multiple structure consisting of a chromium alloy. In such a multiple structure, the heat resistance and pressure resistance of the container are ensured by the outer part made of the first nickel-chromium alloy, and the corrosion resistance of the container is ensured by the inner part made of the second nickel-chromium alloy.

  Therefore, the use of the above structure provides a reaction vessel that can achieve both heat resistance / pressure resistance and corrosion resistance without lining or coating a material such as a platinum group or a noble metal.

  In addition, by using the nitride crystal growth vessel according to the present invention, even when a nitride crystal is grown in a supercritical state or a subcritical state such as ammonia, the contamination of impurities from the vessel is suppressed. Thus, a high-quality nitride crystal can be obtained.

1 Outer wall side (pressure-resistant part P) made of the first nickel-chromium alloy
2 Inner wall side made of the second nickel-chromium alloy (corrosion resistant part C)
3 Baffle plate 4 Raw material 5 Seed crystal 6 Lid 7 Conduit 8 Valve 10 Container 11 Vacuum pump 12 Ammonia cylinder 13 Nitrogen cylinder 14 Mass flow meter 20 Inner cylinder

Claims (17)

A sealable pressure-resistant container used for the growth of nitride crystals,
The outer wall side of the container is made of a first nickel-chromium alloy,
The inner wall side of the container is made of a second nickel-chromium alloy having higher corrosion resistance against a nitrogen-containing solvent than the first nickel-chromium alloy.
A nitride crystal growth vessel.   2. The nitride crystal growth vessel according to claim 1, wherein the second nickel-chromium alloy has a corrosion rate of 0.1 mm / year or less in a nitrogen-containing solvent in a supercritical state or a subcritical state. .   3. The nitride crystal growth container according to claim 1, wherein the second nickel-chromium alloy has a total amount of δ phase amount, η phase amount, and Laves phase amount of 2% or less in area ratio evaluation. .   2. The second nickel-chromium alloy has a sum of δ phase amount, η phase amount, and Laves phase amount after aging at 500 to 700 ° C. for 3000 hours in an area ratio evaluation of 10% or less. The container for growing a nitride crystal according to any one of?   The second nickel-chromium alloy has a tensile strength of 600 to 1300 MPa evaluated in a temperature range of 500 to 700 ° C and an elongation at break of 5% or more. A container for growing a nitride crystal as described in 1. The second nickel-chromium alloy has a ratio (R _H / R ₀ ) of the restriction (R _H %) of the hydrogen-charged material charged with 50 to 60 ppm of hydrogen and the restriction (R ₀ %) of the uncharged material. ) Is 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C. The container for growing a nitride crystal according to claim 5.   The second nickel-chromium alloy has a nickel content of 50 to 80%, a chromium content of 15 to 30%, and an iron content of 5% or less in a weight ratio. 2. A container for growing a nitride crystal according to item 1.   The nitriding according to any one of claims 1 to 7, wherein the first nickel-chromium alloy has a total amount of δ phase amount, η phase amount, and Laves phase amount of 5% or less in area ratio evaluation. Container for crystal growth.   The first nickel-chromium alloy has a sum of δ phase amount, η phase amount, and Laves phase amount after aging at 500 to 700 ° C for 3000 hours, which is 10% or less in area ratio evaluation. The container for nitride crystal growth according to any one of -8.   The first nickel-chromium alloy has a tensile strength of 700 to 1300 MPa evaluated in a temperature range of 500 to 700 ° C and an elongation at break of 5% or more. A container for growing a nitride crystal as described in 1. The first nickel-chromium alloy has a ratio (R _H / R ₀ ) between the restriction (R _H %) of the hydrogen charge material charged with 50 to 60 ppm of hydrogen and the restriction (R ₀ %) of the uncharged material. ) Is a nitride crystal growth container according to claim 10, which is 0.3 or more in a tensile test in a temperature range of 500 to 700 ° C.   The first nickel-chromium alloy according to any one of claims 1 to 11, wherein the first nickel-chromium alloy has a nickel content of 20 to 70%, a chromium content of 10 to 25%, and an iron content of 40% or less. 2. A container for growing a nitride crystal according to item 1.   The container for growing a nitride crystal according to any one of claims 1 to 12, wherein a thickness of the first nickel-chromium alloy layer on the outer wall side of the container is 60 mm or more. A method for producing a nitride crystal using the container according to any one of claims 1 to 13,
Filling the container with a nitrogen-containing solvent to seal the container, and growing the nitride crystal with the nitrogen-containing solvent in the sealed container as a supercritical state to a subcritical state;
A method for producing a nitride crystal, comprising:   The method for producing a nitride crystal according to claim 14, wherein the growth of the nitride crystal is performed at a temperature of 600 ° C. or more.   The method for producing a nitride crystal according to claim 14 or 15, wherein the growth of the nitride crystal is performed under a pressure of 200 MPa or more.   The method for producing a nitride crystal according to any one of claims 14 to 16, wherein the nitrogen-containing solvent is ammonia.