Method for detecting content of hafnium element in directionally solidified high-temperature alloy

Abstract

The invention discloses a method for detecting the content of a hafnium element in a directionally solidified high-temperature alloy, which is specifically implemented according to the following steps: step 1, dissolving a to-be-detected directionally solidified high-temperature alloy to obtain a mixed solution; step 2, adding a hafnium standard solution into the mixed solution to prepare a hafnium working curve solution; 3, selecting a spectral wavelength, and detecting the signal intensity of the hafnium working curve solution; 4, fitting a working curve; and 5, calculating the hafnium concentration in the mixed solution to obtain the content of the hafnium element in the directionally solidified high-temperature alloy sample to be detected. The standard addition method is used for determining the Hf element in the high-temperature alloy through inductively coupled plasma atomic emission spectrometry, the acid ratio is optimized, a sample is dissolved in a mixed system of hydrochloric acid, nitric acid and hydrofluoric acid through a pre-experiment, the problem that the high-tungsten high-temperature alloy is difficult to dissolve is effectively solved, the sample is completely dissolved, the dissolving speed is high, no precipitate exists, acid consumption is low, and the method is suitable for industrial production. And the accuracy and efficiency of subsequent detection are ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alloy analysis, and relates to a detection method for hafnium element content in a directionally solidified high-temperature alloy (DS200+Hf). BACKGROUND

[0002] The DS200+Hf alloy is the first generation of directionally solidified columnar crystal high-temperature alloy prepared by adding Hf elements to the cast alloy Mar-M200 and using a directional solidification process. Due to the adoption of the directional solidification technology and the addition of a small amount of Hf modifier, the alloy has excellent high and medium temperature comprehensive performance, excellent thermal fatigue resistance and good casting performance, and has been widely used in advanced turbojet engines. As an alloying element, hafnium (Hf) is resistant to radiation and corrosion, has a high melting point, can be forged and drawn, and has unique physical and chemical properties and excellent processing performance. However, the extraction method of hafnium is complex, the yield is low, the price is high, and the melting point is high, so it is called a rare refractory metal. It can significantly improve the oxidation resistance, high temperature strength and creep resistance of the alloy. Therefore, the quantitative analysis of hafnium elements in the alloy has very important significance for the research and development of new materials, the production and quality control of new products.

[0003] At present, the detection methods related to the determination of hafnium elements by ICP-AES include GB / T38513-2020, HB20241.8-2016 and the like. In addition, traditional chemical analysis methods include bitter almond acid weight method, EDTA titration method, dimethyl phenol orange spectrophotometry and the like. Compared with traditional chemical analysis methods, the inductively coupled plasma atomic emission spectrometry (ICP-AES) method has the characteristics of high precision, low detection limit, wide linear range of analysis and simultaneous determination of multiple elements, overcomes the cumbersome sample pretreatment process of the chemical method, greatly improves the analysis speed, and the analysis result is accurate and reliable, better meets the requirements of modern production and laboratory daily analysis, and has been widely used in element analysis. In recent years, the use of ICP-AES to analyze the hafnium element content in alloys has attracted the attention of researchers, such as the use of ICP-AES to determine the hafnium element content in WC-Co hard alloy, the use of ICP-AES to determine the hafnium element content in zirconium-titanium placer, and the use of ICP-AES to determine the hafnium and zirconium element content in MHC alloy.

[0004] There is no detection method for hafnium elements in directionally solidified high-temperature alloys represented by DS200+Hf alloy in the prior art, and the existing traditional chemical methods have the disadvantages of more chemical reagents, greater danger, low analysis efficiency and the like. SUMMARY

[0005] The purpose of the present application is to provide a detection method for hafnium element content in a directionally solidified high-temperature alloy, which overcomes the cumbersome sample pretreatment process of the chemical method and improves the analysis speed.

[0006] The technical scheme adopted by the present application is a detection method for the content of hafnium element in a directionally solidified high-temperature alloy, which is specifically implemented according to the following steps: Step 1, dissolving the directionally solidified high-temperature alloy to be detected to obtain a mixed solution; Step 2, adding a hafnium standard solution to the mixed solution to prepare a hafnium working curve solution; Step 3, selecting a spectral wavelength to detect the signal intensity of the hafnium working curve solution; Step 4, fitting the working curve; Step 5, calculating the hafnium concentration in the mixed solution to obtain the content of hafnium element in the directionally solidified high-temperature alloy sample to be detected.

[0007] The present application is also characterized in that: In step 1, the chipped alloy sample of the directionally solidified high-temperature alloy to be detected is weighed into a beaker, 1g / ml-1.2g / ml of hydrochloric acid, 1g / ml-1.5g / ml of nitric acid and 1g / ml-1.2g / ml of hydrofluoric acid are added to the beaker; 85ml-95ml of hydrochloric acid, 25ml-35ml of nitric acid and 25ml-35ml of hydrofluoric acid are added for each gram of the directionally solidified high-temperature alloy sample, after the addition is completed, the solution is heated until the alloy is completely dissolved, and then the mixed solution is cooled to room temperature.

[0008] The heating temperature is 120℃-150℃.

[0009] The concentration of hydrochloric acid is 1.19g / mL, the concentration of nitric acid is 1.4g / mL, and the concentration of hydrofluoric acid is 1.14g / mL.

[0010] In step 2, six mixed solutions are prepared according to step 1, and 0ml / 100ml, 0.50ml / 100ml, 1.00ml / 100ml, 2.00ml / 100ml, 3.00ml / 100ml and 4.00mL / 100ml of hafnium standard solution are added to the mixed solutions respectively; after being diluted to 1L, six hafnium working curve solutions are obtained after being mixed thoroughly.

[0011] In step 2, the concentration of the hafnium standard solution is 1mg / mL.

[0012] In step 3, the hafnium working curve solution of step 2 is placed into an inductively coupled plasma emission spectrometer to detect the signal intensity of the hafnium working curve solution; The spectral wavelength is any one of 264.141nm, 273.846nm, 277.336nm and 282.022nm.

[0013] In step 4, the signal intensity of the hafnium working curve solution detected in step 3 is taken as the ordinate, the hafnium element concentration added in the hafnium working curve solution is taken as the abscissa, the working curve is fitted, and the expression of the working curve is obtained: (1); Wherein A is the signal intensity, C is the hafnium element concentration in the solution, and a and b are coefficients. The spectral wavelength is selected as 282.022 nm, and the expression of the working curve is: A=14141·C+434.62 (2).

[0014] In step 5, the signal intensity A in the working curve expression (1) is zero, and the corresponding hafnium element concentration C is obtained. At this time, the absolute value of C is the hafnium element concentration in the mixed solution. The hafnium element concentration in the mixed solution multiplied by the volume of the mixed solution can obtain the hafnium element content in each gram of the directional solidification high-temperature alloy sample to be detected.

[0015] The beneficial effects of the present application are: (1) The present application optimizes the ratio of acid, discards single acid, aqua regia and traditional complexing / fuming system, and selects the sample pretreatment method through pre-experiment, that is, the mixed system of hydrochloric acid, nitric acid and hydrofluoric acid is used to dissolve the sample, which effectively solves the problem of difficult dissolution of high-tungsten high-temperature alloy, realizes complete dissolution of the sample, has fast dissolution speed, no precipitation and low acid consumption, and guarantees the accuracy and efficiency of subsequent detection.

[0016] (2) The present application uses standard addition method for inductively coupled plasma atomic emission spectrometry to determine the Hf element in high-temperature alloy, which can effectively eliminate the interference of matrix effect without complicated matrix matching steps, effectively solve the problem that matrix matching cannot be realized in blind sample detection, simplify the operation process, and guarantee the accuracy and reliability of the detection result of Hf element in the complex matrix system.

[0017] (3) The present application overcomes the complicated sample pretreatment process of chemical method, improves the analysis speed, reduces the cost, and can meet the needs of production analysis and detection. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is the working curve graph in embodiment 1 of the present application. DETAILED DESCRIPTION

[0019] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0020] The detection method of hafnium element content in directional solidification high-temperature alloy is carried out according to the following steps: Step 1, dissolving the directional solidification high-temperature alloy to be detected to obtain a mixed solution.

[0021] The chippings of the directional solidification high-temperature alloy to be detected are weighed into a beaker, 1 g / ml-1.2 g / ml of hydrochloric acid, 1 g / ml-1.5 g / ml of nitric acid and 1 g / ml-1.2 g / ml of hydrofluoric acid are added to the beaker, 85 ml-95 ml of hydrochloric acid, 25 ml-35 ml of nitric acid and 25 ml-35 ml of hydrofluoric acid are added per gram of alloy sample, after the addition is completed, the solution is heated until the alloy is completely dissolved, and then the mixed solution is cooled to room temperature.

[0022] The heating temperature is 120-150°C. The concentration of hydrochloric acid is 1.19 g / mL, the concentration of nitric acid is 1.4 g / mL, and the concentration of hydrofluoric acid is 1.14 g / mL.

[0023] Step 2, add hafnium standard solution to the mixed solution to prepare hafnium working curve solution.

[0024] According to step 1, six mixed solutions are prepared, and 0 ml / 100 ml, 0.50 ml / 100 ml, 1.00 ml / 100 ml, 2.00 ml / 100 ml, 3.00 ml / 100 ml and 4.00 mL / 100 ml of hafnium standard solution are added to the mixed solutions, that is, 0 ml, 0.50 ml, 1.00 ml, 2.00 ml, 3.00 ml and 4.00 mL of hafnium standard solution are added to every 100 ml of mixed solution in the six mixed solutions.

[0025] After dilution and thorough mixing, six hafnium working curve solutions are obtained. After the mixed solution after dissolving per gram of alloy sample is added with hafnium standard solution, it is diluted to 1 L; The concentration of hafnium standard solution is 1 mg / mL.

[0026] Step 3, select the spectral wavelength, and detect the signal intensity of the hafnium working curve solution.

[0027] The six hafnium working curve solutions of step 2 are all placed into an inductively coupled plasma emission spectrometer, and the signal intensity of the hafnium working curve solution is detected.

[0028] The DS200+Hf alloy has a complex composition, with high contents of W, Cr and Co, and in addition, Al, Ti, Nb, B, Zr, Fe, Cu, Mn, Si and P. When ICP-AES analysis is performed, there is overlapping spectral interference of coexisting alloy elements, so it is necessary to select an analysis spectral line with less interference and high sensitivity to determine the optimal wavelength of the analysis spectral line.

[0029] The spectral wavelengths can be selected from 264.141nm, 273.846nm, 277.336nm and 282.022nm.

[0030] The specific operating parameters of the inductively coupled plasma atomic emission spectrometer are as follows: plasma power: 1150W; integration time: 15s for short wave and 5s for long wave; pump speed: 45r / min; carrier gas flow rate: 0.50L / min; auxiliary gas flow rate: 0.5L / min; cooling gas flow rate: 12.5L / min; nebulizer gas flow rate: 0.90L / min; vertical observation height: 10.0mm; sample lift rate: 1.5mL / min; repeatability: 3 times; working gas: high-purity argon (≥99.995%); working pressure: 0.55MPa~0.6MPa; circulating cooling water temperature: 20℃; minimum flow rate: 2L / min; exhaust velocity: 5.5m / s; sample processing time: 60s; exposure time: 30s.

[0031] Step 4: Fit the working curve.

[0032] Using the signal intensity of the hafnium working curve solution detected in step 3 as the ordinate and the concentration of hafnium added to the hafnium working curve solution as the abscissa, the working curve is fitted, and the expression of the working curve is obtained: (1) Where A is the signal intensity, C is the hafnium concentration in the solution, and a and b are coefficients; a and b are obtained during the fitting process.

[0033] Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0034] Make the signal intensity A in the working curve expression (1) zero, and obtain the corresponding hafnium element concentration C. At this time, the absolute value of C is the hafnium element concentration in the mixed solution. Multiply the hafnium element concentration in the mixed solution by the volume of the mixed solution to obtain the hafnium element content in each gram of the directionally solidified high-temperature alloy sample to be tested.

[0035] When the spectral wavelength is selected as 282.022 nm, the specific fitting of the working curve is as follows: A = 14141·C + 434.62 (2).

[0036] Example 1 The method for detecting the hafnium content in directionally solidified superalloys shall be carried out according to the following steps: Step 1: Dissolve the directional solidified high-temperature alloy to be tested to obtain a mixed solution.

[0037] Weigh 0.1 g of the shavings of the directionally solidified superalloy to be tested into a beaker. Add 9 ml of 1.19 g / mL hydrochloric acid, 3 ml of 1.4 g / mL nitric acid, and 3 ml of 1.14 g / mL hydrofluoric acid to the beaker. After the addition is complete, heat the solution to 130°C until the alloy is completely dissolved, and then cool the mixture to room temperature.

[0038] Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution.

[0039] According to step 1, prepare six mixed solutions. Add 0 ml, 0.50 ml, 1.00 ml, 2.00 ml, 3.00 ml and 4.00 ml of hafnium standard solution to the mixed solutions respectively. After thorough mixing, obtain six hafnium working curve solutions and make up to 100 ml for each solution.

[0040] The concentration of the hafnium standard solution is 1 mg / mL.

[0041] Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution.

[0042] The six hafnium working curve solutions from step 2 were all placed in an inductively coupled plasma atomic emission spectrometer to detect the signal intensity of the hafnium working curve solutions.

[0043] The spectral wavelength was selected as 282.022 nm.

[0044] The specific operating parameters of the inductively coupled plasma atomic emission spectrometer are as follows: plasma power: 1150W; integration time: 15s for short wave and 5s for long wave; pump speed: 45r / min; carrier gas flow rate: 0.50L / min; auxiliary gas flow rate: 0.5L / min; cooling gas flow rate: 12.5L / min; nebulizer gas flow rate: 0.90L / min; vertical observation height: 10.0mm; sample lift rate: 1.5mL / min; repeatability: 3 times; working gas: high-purity argon (≥99.995%); working pressure: 0.55MPa~0.6MPa; circulating cooling water temperature: 20℃; minimum flow rate: 2L / min; exhaust velocity: 5.5m / s; sample processing time: 60s; exposure time: 30s.

[0045] The specific test results are shown in Table 1.

[0046] Table 1 Signal Intensity of Hafnium Working Curve Solution

[0047] Step 4: Fit the working curve.

[0048] The signal intensity of the hafnium working curve solution detected in step 3 is used as the ordinate, and the concentration of hafnium added to the hafnium working curve solution is used as the abscissa.

[0049] Working curve fitting as follows Figure 1 As shown, the working curve is: A = 14141·C + 434.62 (2).

[0050] Where A is the signal intensity, C is the concentration of hafnium in the solution, and the correlation coefficient r = 0.9998.

[0051] Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0052] By setting the signal intensity A in the working curve to 0, the corresponding hafnium element concentration C is calculated to be 0.031 mg / mL, which is the hafnium element concentration in the mixed solution. Multiplying the hafnium element concentration in the mixed solution by the volume of the mixed solution gives the hafnium element content in the 0.1 g directionally solidified superalloy sample to be tested to be 0.031 mg.

[0053] Example 2 The method for detecting hafnium content in directionally solidified superalloys shall be implemented according to the following steps: Step 1: Dissolve the directionally solidified high-temperature alloy to be tested to obtain a mixed solution; Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution; Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution; Step 4: Fit the working curve; Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0054] Example 3 The method for detecting hafnium content in directionally solidified superalloys shall be implemented according to the following steps: Step 1: Dissolve the directionally solidified high-temperature alloy to be tested to obtain a mixed solution; Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution; Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution; Step 4: Fit the working curve; Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0055] In step 1, weigh the shavings of the directionally solidified superalloy to be tested into a beaker, and add 1 g / ml to 1.2 g / ml hydrochloric acid, 1 g / ml to 1.5 g / ml nitric acid, and 1 g / ml to 1.2 g / ml hydrofluoric acid to the beaker; for each gram of directionally solidified superalloy sample, add 85 ml to 95 ml of hydrochloric acid, 25 ml to 35 ml of nitric acid, and 25 ml to 35 ml of hydrofluoric acid. After the addition is complete, heat the solution until the alloy is completely dissolved, and then cool the mixed solution to room temperature.

[0056] Example 4 The method for detecting hafnium content in directionally solidified superalloys shall be implemented according to the following steps: Step 1: Dissolve the directionally solidified high-temperature alloy to be tested to obtain a mixed solution; Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution; Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution; Step 4: Fit the working curve; Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0057] In step 1, weigh the shavings of the directionally solidified superalloy to be tested into a beaker, and add 1 g / ml to 1.2 g / ml hydrochloric acid, 1 g / ml to 1.5 g / ml nitric acid, and 1 g / ml to 1.2 g / ml hydrofluoric acid to the beaker; for each gram of directionally solidified superalloy sample, add 85 ml to 95 ml of hydrochloric acid, 25 ml to 35 ml of nitric acid, and 25 ml to 35 ml of hydrofluoric acid. After the addition is complete, heat the solution until the alloy is completely dissolved, and then cool the mixed solution to room temperature.

[0058] The heating temperature is 120℃~150℃.

[0059] Example 5 The method for detecting hafnium content in directionally solidified superalloys shall be implemented according to the following steps: Step 1: Dissolve the directionally solidified high-temperature alloy to be tested to obtain a mixed solution; Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution; Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution; Step 4: Fit the working curve; Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0060] In step 1, weigh the shavings of the directionally solidified superalloy to be tested into a beaker, and add 1 g / ml to 1.2 g / ml hydrochloric acid, 1 g / ml to 1.5 g / ml nitric acid, and 1 g / ml to 1.2 g / ml hydrofluoric acid to the beaker; for each gram of directionally solidified superalloy sample, add 85 ml to 95 ml of hydrochloric acid, 25 ml to 35 ml of nitric acid, and 25 ml to 35 ml of hydrofluoric acid. After the addition is complete, heat the solution until the alloy is completely dissolved, and then cool the mixed solution to room temperature.

[0061] The concentrations of hydrochloric acid, nitric acid, and hydrofluoric acid were 1.19 g / mL, 1.4 g / mL, and 1.14 g / mL, respectively.

[0062] Example 6 The method for detecting hafnium content in directionally solidified superalloys shall be implemented according to the following steps: Step 1: Dissolve the directionally solidified high-temperature alloy to be tested to obtain a mixed solution; Step 2: Add hafnium standard solution to the mixed solution to prepare the hafnium working curve solution; Step 3: Select the spectral wavelength and detect the signal intensity of the hafnium working curve solution; Step 4: Fit the working curve; Step 5: Calculate the hafnium concentration in the mixed solution to obtain the hafnium content in the directionally solidified high-temperature alloy sample to be tested.

[0063] In step 2, six mixed solutions are prepared according to step 1. Hafnium standard solutions of 0 ml / 100 ml, 0.50 ml / 100 ml, 1.00 ml / 100 ml, 2.00 ml / 100 ml, 3.00 ml / 100 ml, and 4.00 ml / 100 ml are added to the mixed solutions respectively. After making up the volume and mixing thoroughly, six hafnium working curve solutions are obtained. After dissolving each gram of alloy sample, hafnium standard solution is added to the mixed solution and the volume is made up to 1 L.

Claims

1. A method for detecting the content of hafnium element in a directionally solidified superalloy, characterized in that, Specifically, the following steps are implemented: Step 1, dissolve the directional solidification superalloy to be detected to obtain a mixed solution; Step 2, add hafnium standard solution to the mixed solution to prepare a hafnium working curve solution; Step 3, select a spectral wavelength to detect the signal intensity of the hafnium working curve solution; Step 4, fit the working curve; Step 5, calculate the hafnium concentration in the mixed solution to obtain the hafnium element content in the directional solidification superalloy sample to be detected.

2. The method of claim 1, wherein the method is characterized by, In step 1, the chipped alloy sample of the directional solidification superalloy to be detected is weighed into a beaker, 1g / ml-1.2g / ml of hydrochloric acid, 1g / ml-1.5g / ml of nitric acid and 1g / ml-1.2g / ml of hydrofluoric acid are added to the beaker; 85ml-95ml of hydrochloric acid, 25ml-35ml of nitric acid and 25ml-35ml of hydrofluoric acid are added for each gram of directional solidification superalloy sample, after the addition is completed, the solution is heated until the alloy is completely dissolved, and then the mixed solution is cooled to room temperature.

3. The method for detecting hafnium content in directionally solidified superalloys according to claim 2, characterized in that, The heating temperature is 120-150℃.

4. The method for detecting hafnium content in directionally solidified superalloys according to claim 2, characterized in that, The concentration of hydrochloric acid is 1.19g / mL, the concentration of nitric acid is 1.4g / mL, and the concentration of hydrofluoric acid is 1.14g / mL.

5. The method of claim 1, wherein the method is characterized by: In step 2, six mixed solutions are prepared according to step 1, and 0ml / 100ml, 0.50ml / 100ml, 1.00ml / 100ml, 2.00ml / 100ml, 3.00ml / 100ml and 4.00mL / 100ml of hafnium standard solution are added to the mixed solutions respectively; after constant volume and thorough mixing, six hafnium working curve solutions are obtained; after the hafnium standard solution is added to the mixed solution after the alloy sample is dissolved, the volume is adjusted to 1L.

6. The method for detecting hafnium content in directionally solidified superalloys according to claim 5, characterized in that, In step 2, the concentration of hafnium standard solution is 1mg / mL.

7. The method for detecting hafnium content in directionally solidified superalloys according to claim 1, characterized in that, In step 3, the hafnium working curve solution of step 2 is placed into an inductively coupled plasma emission spectrometer to detect the signal intensity of the hafnium working curve solution; The spectral wavelength is any one of 264.141nm, 273.846nm, 277.336nm and 282.022nm.

8. The method for detecting hafnium content in directionally solidified superalloys according to claim 1, characterized in that, In step 4, the signal intensity of the hafnium working curve solution detected in step 3 is taken as the ordinate, and the concentration of hafnium element added in the hafnium working curve solution is taken as the abscissa, the working curve is fitted, and the expression of the working curve is obtained: （1）； Where A is the signal intensity, C is the concentration of hafnium element in the solution, and a and b are coefficients.

9. The method for detecting hafnium content in directionally solidified superalloys according to claim 8, characterized in that, The spectral wavelength is selected as 282.022nm, and the expression of the working curve is: A=14141·C+434.62(2).

10. The method for detecting hafnium content in directionally solidified superalloys according to claim 8, characterized in that, In step 5, the signal intensity A in the working curve expression (1) is zero, and the corresponding hafnium element concentration C is obtained, and the absolute value of C is the hafnium element concentration in the mixed solution. The hafnium element concentration in the mixed solution multiplied by the volume of the mixed solution can obtain the hafnium element content in each gram of the directional solidification superalloy sample to be detected.

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