Method for measuring argon content in high-temperature alloy powder

Abstract

The invention belongs to the technical field of detection of the content of gas elements in high-temperature alloy powder, and particularly relates to a method for measuring the content of argon in high-temperature alloy powder. A pulse heating-thermal conductivity method is used for detection, a sample is fed in a direct feeding mode, and the method mainly comprises the steps of parameter setting, blank deduction, working curve establishment and sample detection. According to the method, by optimizing a detection program and a sample introduction mode, the interference of gas adsorbed on the surface of the powder and internal compound nitrogen is effectively eliminated, and the argon content is accurately and reliably measured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection of gas element content in high-temperature gold alloy powder, and particularly relates to a method for determining the content of argon in high-temperature alloy powder. BACKGROUND

[0002] Powder high-temperature alloy has become an irreplaceable material for key components such as turbine discs and blades of aerospace engine due to its excellent high-temperature strength, fatigue resistance, oxidation resistance and corrosion resistance. With the expansion of application fields and the improvement of performance requirements, it is crucial to ensure the high purity and uniformity of the material.

[0003] In the powder preparation stage, argon is often used as an atomization medium (such as argon atomization method) or a protective atmosphere, and its content directly affects the quality of the final product. Appropriate amount of argon helps to reduce powder oxidation, reduce impurity inclusions, and thus improve the purity, microstructure uniformity and comprehensive mechanical properties of the alloy. Therefore, accurate determination of the argon content in high-temperature alloy powder is a key link for evaluating the process level and controlling the product quality.

[0004] However, the accurate determination of the argon content in high-temperature alloy powder faces significant challenges: It is difficult to exclude interfering gases: the powder has a large specific surface area and is easy to adsorb nitrogen, oxygen and other gases in the air. During the detection process, these adsorbed gases will be released together with the internal argon, seriously interfering with the detection signal and leading to high results.

[0005] Limitations of existing methods: In the determination of argon by traditional inert gas melting-thermal conductivity method, it is usually difficult to completely suppress the release of combined nitrogen in the powder while releasing argon. Nitrogen and argon will both produce responses in the thermal conductivity cell, and it is difficult to distinguish them, resulting in inaccurate detection results.

[0006] Sample introduction method introduces errors: to avoid powder splashing, the sample is often wrapped with a nickel capsule or a nickel foil. However, the wrapping material itself may adsorb gases or contain trace amounts of gas impurities, which will introduce uncontrollable blank values and affect the accuracy and repeatability of the detection.

[0007] Currently, there is a lack of a special detection method for the argon content in high-temperature alloy powder that can effectively distinguish and exclude the interference of surface adsorbed gas and internal combined nitrogen, has stable blank value and simple operation. Therefore, it is of great practical significance to develop a precise and reliable determination technology to promote the quality control and process optimization of powder high-temperature alloy. SUMMARY

[0008] In view of the problems in the prior art, the present application provides a method for determining the argon content in high-temperature alloy powder. The method optimizes the detection procedure and sampling mode, aims to effectively eliminate the interference of adsorbed gas on the surface of the powder and internal combined nitrogen, and realizes accurate and reliable determination of the argon content.

[0009] The technical solution of the present application is: A method for determining the argon content in high-temperature alloy powder, which adopts pulse heating-thermal conductivity method for detection and uses direct injection mode for sample injection, comprising the following steps: (1) Parameter setting: setting a cycle detection program containing degassing I, degassing II, analysis I, degassing III and analysis II on the oxygen and nitrogen analyzer; (2) Blank deduction: running the set program to determine the self blank value of the instrument system, determining not less than 3 times in parallel, and taking the average value as the blank correction value to deduct the subsequent detection results; (3) Working curve establishment: establishing the calibration curve of the instrument response and argon content by introducing argon standard gas with known concentration into the device; excluding the influence of uneven distribution of argon in the alloy standard sample, the value is more accurate; (4) Sample detection: after completing the degassing I in step (1), the high-temperature alloy powder sample to be tested is injected into the device in the direct injection mode, and then the degassing II and analysis I are carried out in sequence to remove the adsorbed gas on the surface of the sample, and then the degassing III and analysis II are carried out to detect and calculate the argon content in the interior of the sample.

[0010] Further, in step (1) of the above method, the functions of each stage of the cycle detection program are: degassing I is used to remove residual gas in the crucible and the device; degassing II and analysis I are used to remove the adsorbed gas impurities on the surface of the sample; and degassing III and analysis II are used to release and detect the argon in the interior of the sample.

[0011] Further, in step (1) of the above method, the temperature parameters of each stage are set as follows: the degassing I temperature is 1900-2200℃, the degassing II and analysis I temperature is 400-500℃, and the degassing III and analysis II temperature is 800-1100℃.

[0012] Further, in step (1) of the above method, the time parameters of each stage are set as follows: the time of degassing I, degassing II and degassing III is 20-30s, and the time of analysis I and analysis II is 40-50s.

[0013] Further, in step (4) of the above method, the sample weight of the high-temperature alloy powder to be tested is 0.2-0.3g.

[0014] Further, in step (2) of the above method, the standard of the system blank value is that the oxygen content and the nitrogen content are both less than 0.0003%.

[0015] Further, in step (3) of the above method, a known concentration of argon standard gas is introduced through a quantitative tube to establish a calibration curve.

[0016] Further, in step (4) of the above method, the direct injection refers to that the sample is not wrapped by a nickel capsule or a nickel foil, but is directly injected into the graphite crucible of the device.

[0017] The present application uses the parameters of the oxygen-nitrogen analyzer to determine the argon content in the powder by the direct injection method. After the powder is completely dissolved, the oxygen element is released in the form of CO / CO2 into the infrared absorption cell for analysis, the nitrogen element is released in the form of N2 into the thermal conductivity cell for analysis, and the argon element in the present application is released in the form of Ar into the thermal conductivity cell for analysis. The present application has the advantages that by controlling the parameters, only Ar is released, nitrogen is still in the powder, the interference of nitrogen element on Ar is excluded, the accuracy of detection is ensured, and the specific performances are that the segmented degassing analysis can exclude the interference of the adsorbed gas on the surface of the powder on the detection of argon; the segmented heating can separate and detect the gas in different states; the temperature control prevents the release of nitrogen element in the powder and the interference with the detection of argon; the present application adopts the direct injection method to feed the material, the influence of the nickel capsule / nickel foil on the blank is excluded, and the data is reliable and accurate. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below in combination with specific embodiments. However, the implementation and protection scope of the present application are not limited thereto.

[0019] Example 1 In this embodiment, the argon content in GH4169 high-temperature alloy powder (particle size 15-53 μm) is determined.

[0020] 1. Reagents and materials Equipment: pulse heating-thermal conductivity method oxygen-nitrogen analyzer, analytical balance.

[0021] Consumables: high-purity graphite sleeve crucible, high-purity helium gas (carrier gas, purity ≥ 99.999%), high-purity nitrogen gas (optional, used for instrument maintenance), magnesium perchlorate (water absorbent), and alkali asbestos (CO2 absorber).

[0022] Standard substance: 99.999% high-purity argon gas and a series of argon standard gas prepared by using helium as dilution gas.

[0023] 2. Instrument parameter setting The following detection program is set on the oxygen-nitrogen analyzer: Program steps: degassing one → degassing two → analysis one → degassing three → analysis two.

[0024] Temperature parameters: degassing 1: 2100°C; degassing 2 and analysis 1: 450°C; degassing 3 and analysis 2: 950°C.

[0025] Time parameters: degassing 1, degassing 2, degassing 3: 25 s; analysis 1, analysis 2: 45 s.

[0026] 3. Blank test and correction A new high-purity graphite sleeve crucible was placed on the electrode under the analyzer, and the above setting program was run for blank determination, and determination was continuously performed for 3 times. The results are shown in the following table: Table 1 Blank test results of Example 1 Serial number Oxygen blank value (%) Nitrogen blank value (%) 1# 0.00021 0.00025 2# 0.00019 0.00026 3# 0.00021 0.00026 Average value 0.00020 0.00026 As shown in the above table, the average values of the oxygen and nitrogen contents determined for three times are less than 0.0003%, which meets the requirements. The average value is set as the automatic blank correction value of the instrument.

[0027] 4. Establishment of working curve A quantitative tube was used to inject standard gas samples with argon content of 0.0020% (A), 0.0040% (B), and 0.0060% (C) into the instrument for detection, and each concentration point was determined in parallel for 3 times. The results are shown in the following table: Table 2 Parallel detection results of Example 1 Number 1#（%） 2#（%） 3#（%） RSD (%) Average value A 0.0019 0.0018 0.0019 <0.1 0.0019 B 0.0038 0.0037 0.0039 <0.1 0.0038 C 0.0059 0.0060 0.0060 <0.1 0.0060 As shown in the above table, the data has good parallelism (RSD < 0.1%), and the theoretical value of the standard gas is taken as the abscissa, and the average value measured by the instrument is taken as the ordinate, to establish a linear calibration curve of argon content.

[0028] 5. Sample determination 0.25 g of GH4169 high-temperature alloy powder sample was accurately weighed. The instrument analysis program was started, and after the "degassing 1" stage was completed, the sample was quickly poured into the graphite crucible in a direct injection manner, and the instrument automatically completed all subsequent steps. Parallel determination was performed for 3 times. The results are as follows: Table 3 Sample determination results of Example 1 Number 1#（%） 2#（%） 3#（%） Average value GH4169 0.0045 0.0042 0.0046 0.0044 6. Method verification To further verify the accuracy, according to the above sample determination average value (0.0044%), an argon standard gas sample D with similar concentration was prepared. It was determined for 3 times, and the results are as follows: Table 4 Detection results of argon standard gas sample D of Example 1 Number 1#（%） 2#（%） 3#（%） Average value D 0.0044 0.0044 0.0045 0.0044 The measured value of the standard gas D is highly consistent with the prepared value, indicating that the method has high accuracy and can be reliably used for determination of the argon content in GH4169 high-temperature alloy powder.

[0029] Example 2 This example determines the argon content in GH3230 high-temperature alloy powder (particle size 15-53 μm) 1. Reagents and materials Equipment: Pulse heating-thermal conductivity method oxygen and nitrogen analyzer, analytical balance.

[0030] Consumables: High-purity graphite sleeve crucible, high-purity helium gas (carrier gas, purity ≥ 99.999%), high-purity nitrogen gas (optional, for instrument maintenance), magnesium perchlorate (water absorbent), alkali asbestos (absorbs CO2).

[0031] Standard substance: 99.999% high-purity argon gas and a series of argon gas standard gases prepared using helium gas as diluent gas.

[0032] 2. Instrument parameter setting Set the following detection program on the oxygen and nitrogen analyzer: Program steps: degassing 1 → degassing 2 → analysis 1 → degassing 3 → analysis 2.

[0033] Temperature parameters: degassing 1: 1900℃; degassing 2 and analysis 1: 400℃; degassing 3 and analysis 2: 900℃.

[0034] Time parameters: degassing 1, degassing 2, and degassing 3 are all 30s; analysis 1 and analysis 2 are both 50s.

[0035] 3. Blank experiment and correction Place a new high-purity graphite sleeve crucible on the lower electrode of the analyzer, and run the above setting program for blank determination, continuously determine for 3 times. The results are shown in the following table: Table 5 Blank test results of Example 2 Serial number Oxygen blank value (%) Nitrogen blank value (%) 1# 0.00019 0.00024 2# 0.00020 0.00025 3# 0.00020 0.00025 Average value 0.00020 0.00025 As can be seen from the above table, the average value of the oxygen and nitrogen contents determined for three times is less than 0.0003%, which meets the requirements. Set this average value as the automatic blank correction value of the instrument.

[0036] 4. Establishment of working curve Use a quantitative tube to inject argon gas samples with argon contents of 0.0080% (E), 0.0100% (F), and 0.0120% (G) into the instrument for detection, and determine each concentration point in parallel for 3 times. The results are as follows: Table 6 Parallel detection results of Example 2 Number 1#（%） 2#（%） 3#（%） RSD (%) Average value E 0.0079 0.0078 0.0079 <0.1 0.0079 F 0.0101 0.0102 0.0101 <0.1 0.0101 G 0.0119 0.0120 0.0120 <0.1 0.0120 From the table above, it can be seen that the data has good parallelism (RSD < 0.1 %). The linear calibration curve of argon content is established by taking the theoretical value of the standard gas as the horizontal coordinate and the average value measured by the instrument as the vertical coordinate.

[0037] 5. Sample determination 0.3 g of GH3230 high-temperature alloy powder sample was accurately weighed. The instrument analysis program was started, and after the "degassing I" stage was completed, the sample was directly poured into the graphite crucible in a direct injection manner, and the instrument automatically completed all subsequent steps. The determination was performed in triplicate. The results are as follows: Table 7 Determination results of the sample in Example 2 Number 1#（%） 2#（%） 3#（%） Average value GH4169 0.0109 0.0110 0.0108 0.0109 6. Method verification To further verify the accuracy, according to the average value of the above sample determination (0.0109 %), an argon standard gas sample H with an approximate concentration was prepared. The determination was performed in triplicate, and the results are as follows: Table 8 Determination results of the argon standard gas sample H in Example 2 Number 1#（%） 2#（%） 3#（%） Average value H 0.0110 0.00112 0.0111 0.0111 The measured value of the standard gas H is highly consistent with the prepared value, indicating that the method has high accuracy and can be reliably used for the determination of the argon content in the GH3230 high-temperature alloy powder.

Claims

1. A method for determining the argon content in high-temperature alloy powder, characterized in that, The detection was performed using the pulse heating-thermal conductivity method, and the sample was delivered via direct injection, including the following steps: (1) Parameter setting: Set a cyclic detection program on the oxygen and nitrogen analyzer that includes degassing I, degassing II, analysis I, degassing III, and analysis II; (2) Blank subtraction: Run the set program, measure the instrument system’s own blank value, perform parallel measurements no less than 3 times, and take the average value as the blank correction value to subtract from the subsequent test results; (3) Establishment of working curve: By introducing argon standard gas of known concentration into the equipment, a calibration curve of instrument response and argon content is established; the influence of uneven distribution of argon in alloy standard sample is eliminated, and the value is more accurate. (4) Sample detection: After completing the first degassing step (1), the high-temperature alloy powder sample to be tested is directly put into the equipment and degassed and analyzed in sequence to remove the adsorbed gas on the sample surface. Then degassed and analyzed in sequence to detect and calculate the argon content inside the sample.

2. The method according to claim 1, characterized in that, In step (1), the functions of each stage of the cyclic detection program are as follows: Degassing I is used to remove residual gas in the crucible and equipment; Degassing II and Analysis I are used to remove gaseous impurities adsorbed on the sample surface; Degassing III and Analysis II are used to release and detect argon gas inside the sample.

3. The method according to claim 2, characterized in that, In step (1), the temperature parameters for each stage are set as follows: the temperature for degassing stage 1 is 1900℃-2200℃, the temperature for degassing stage 2 and analysis stage 1 is 400℃-500℃, and the temperature for degassing stage 3 and analysis stage 2 is 800℃-1100℃.

4. The method according to claim 2 or 3, characterized in that, In step (1), the time parameters for each stage are set as follows: the time for degassing I, degassing II, and degassing III is 20s-30s, and the time for analysis I and analysis II is 40s-50s.

5. The method according to claim 1, characterized in that, In step (4), the sample weight of the high-temperature alloy powder to be tested is 0.2g-0.3g.

6. The method according to claim 1, characterized in that, In step (2), the standard for the system blank value is that both the oxygen content and nitrogen content are less than 0.0003%.

7. The method according to claim 1, characterized in that, In step (3), a standard argon gas of known concentration is introduced through a metering tube to establish a calibration curve.

8. The method according to claim 1, characterized in that, In step (4), the direct-injection method means that the sample is directly put into the graphite crucible of the equipment without being wrapped in a nickel bag or nickel foil.