Method for detecting contents of titanium and cobalt elements in precipitated iron-nickel-based superalloy

Abstract

The invention provides a method for detecting the content of titanium and cobalt elements in a precipitation type iron-nickel-based superalloy, and belongs to the technical field of chemical analysis and detection of alloy macroelements. The method solves the problems of high detection cost, long time consumption, low accuracy and the like of the titanium and cobalt elements in the precipitation type iron-nickel-based superalloy. The method comprises the following steps: dissolving an alloy by using aqua regia, performing smoking treatment by using sulfur-phosphorus mixed acid, adding water to a constant volume to obtain mother liquor, and respectively measuring the contents of titanium and cobalt by using the same mother liquor; titanium is measured in an acidic medium, titanium ions react with diantipyrine methane to generate a yellow complex, and the complex has a specific absorption wavelength in a visible light region and can be measured by using a spectrophotometric method; the cobalt is determined by forming a colored complex by using cobalt ions and nitroso red salt molecules, and the complex has a specific absorption wavelength in a visible light region and can be determined by using spectrophotometry. The detection method provided by the invention has the advantages of high sensitivity, good stability, high accuracy, strong anti-interference performance and the like.

Description

Technical Field

[0001] The invention belongs to the field of chemical analysis and detection of alloy constant elements, and specifically relates to a method for detecting the content of titanium and cobalt elements in a precipitated iron-nickel based high temperature alloy. Background Art

[0002] As an important engineering material, precipitated iron-nickel-based superalloys have been widely used in aviation, aerospace, petrochemical, automotive, electronics and electricity due to their excellent corrosion resistance, high temperature strength and good processing performance. Titanium is mainly used as a strong deoxidizer and grain refiner in precipitated iron-nickel-based superalloys. It can make the internal structure of the material dense, refine the grains, reduce aging sensitivity and cold brittleness, thereby improving welding performance. In addition, titanium can also improve the oxidation resistance and creep resistance of precipitated iron-nickel-based superalloys, especially in high temperature environments. The effect of titanium is particularly significant. The addition of cobalt can significantly improve the strength, hardness and wear resistance of precipitated iron-nickel-based superalloys. At the same time, cobalt can also improve the oxidation resistance and thermal fatigue resistance of precipitated iron-nickel-based superalloys, making them perform well in high temperature and corrosive environments. It can be seen that the presence and content of titanium and cobalt elements have an important influence on the performance of precipitated iron-nickel-based superalloys. Therefore, the accurate detection of titanium and cobalt elements in precipitated iron-nickel-based superalloys is particularly important. The main methods for element analysis and determination in precipitated iron-nickel based high temperature alloys include inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), fluorescence analysis, etc. The traditional analysis methods are to determine titanium and cobalt separately, which has the disadvantages of high cost and long time. In addition, the traditional detection methods are easily interfered by other impurity ions, and the detection accuracy of titanium and cobalt content is low. Summary of the invention

[0003] The present invention provides a method for detecting the content of titanium and cobalt elements in a precipitated iron-nickel-based high-temperature alloy in order to solve the technical problems of high cost, long time consumption and low accuracy in detecting titanium and cobalt elements in a precipitated iron-nickel-based high-temperature alloy.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] The object of the present invention is to provide a method for detecting the content of titanium and cobalt elements in a precipitated iron-nickel-based high-temperature alloy, comprising:

[0006] (1) Preparation of mother solution and standard curve matrix solution: Weigh 0.2000 g of the sample to be tested and place it in a conical flask, add aqua regia to dissolve the sample to be tested, then add sulfuric acid and phosphoric acid mixture, heat and evaporate until smoking, add 40 mL of water to boil after cooling, then cool to room temperature, pour into a volumetric flask, make up to volume, shake well to obtain a mother solution, and then perform a blank experiment without adding the sample to be tested to obtain a standard curve matrix solution;

[0007] (2) Determination of titanium by diantipyryl methane spectrophotometry: Two portions of the mother liquor were transferred into two volumetric flasks respectively as test solutions. 10 mL of hydrochloric acid solution and 5 mL of ascorbic acid solution were added to one portion of the test solution. After standing, 10 mL of diantipyryl methane solution was added, water was added to make up the volume, and the solution was shaken and allowed to stand for a period of time as a color developing solution for use. 10 mL of hydrochloric acid solution and 5 mL of ascorbic acid solution were added to the other portion of the test solution. Water was added to make up the volume, and the solution was shaken and allowed to stand for a period of time to obtain a blank solution. The absorbance of the color developing solution was measured at a wavelength of 380 or 420 nm using a spectrophotometer with the blank solution as a reference.

[0008] (3) Determination of cobalt by nitroso red salt photometric method: Pipette two portions of the mother liquor and place them in steel volumetric flasks respectively as the test solution. Add 10 mL of water, 10 mL of sodium acetate solution and 30 mL of nitroso red salt solution to one portion of the test solution, boil it, cool it for 1 min, add 5 mL of HNO3, boil it again, cool it to room temperature, add water to make up the volume, shake it well and let it stand for a while as the color developing solution. Add 5 mL of HNO3, 10 mL of sodium acetate solution and 30 mL of nitroso red salt solution to the other portion of the test solution, add water to make up the volume, shake it well and let it stand for a while as the blank solution. Measure the absorbance of the color developing solution at a wavelength of 520 nm on a spectrophotometer with the blank solution as a reference.

[0009] (4) Drawing of standard curve and calculation of element content: Standard curves were drawn using titanium standard stock solution and cobalt standard stock solution, respectively, and the contents of titanium and cobalt were calculated.

[0010] It is further defined that the sulfur-phosphorus mixed acid in (1) is composed of sulfuric acid, phosphoric acid and water in a volume ratio of 3:6:11.

[0011] It is further defined that the amount of aqua regia used in (1) is 100 mL.

[0012] It is further defined that the amount of sulfuric acid mixed acid used in (1) is 40 mL.

[0013] It is further defined that the dissolution temperature in (1) is 180-220°C and the dissolution time is 5 minutes.

[0014] It is further defined that the smoking time in (1) is 1 minute.

[0015] Further defined, the preparation method of the ascorbic acid solution in (2) is: weigh 20g of ascorbic acid, add water to dissolve it, and then dilute it to 1000mL to obtain an ascorbic acid solution; the preparation method of the diantipyrine methane solution is: weigh 50g of diantipyrine methane, add 1.0mol / L hydrochloric acid solution to dissolve it, and then dilute it to 1000mL with 1.0mol / L hydrochloric acid solution to obtain a diantipyrine methane solution.

[0016] It is further specified that the color developing solution and the blank solution in (2) and (3) should be placed in a state of being kept for 10 to 20 minutes after being shaken during preparation.

[0017] It is further defined that the two mother liquor transfer volumes in (2) are both 10.0 mL or both are 5.0 mL; and the specifications of the two volumetric flasks are both 100 mL or both are 200 mL.

[0018] It is further defined that the preparation method of the sodium acetate solution in (3) is: weigh 500 g of sodium acetate, add water to dissolve it, and then dilute it to 1000 mL to obtain a sodium acetate solution; the preparation method of the nitroso red salt solution is: weigh 3 g of nitroso red salt, add water to dissolve it, and then dilute it to 1000 mL to obtain a nitroso red salt solution.

[0019] It is further defined that the two mother liquor transfer volumes in (3) are both 4.0 mL or both are 2.0 mL; and the specifications of the two steel volumetric flasks are both 100 mL or both are 200 mL.

[0020] It is further specified that the boiling and re-boiling times in (3) are both 1 to 2 minutes.

[0021] The beneficial effects achieved by the present invention are as follows:

[0022] The present invention aims at the problems of instrument fluctuation, matrix effect and spectral interference when the titanium and cobalt contents in the precipitated iron-nickel-based alloy are detected by conventional methods such as ICP-AES, ICP-MS, AAS and fluorescence analysis, and the problems of long detection time, large error and high cost when the titanium and cobalt contents in the precipitated iron-nickel-based alloy are determined separately. A detection method for titanium and cobalt elements in the precipitated iron-nickel-based high-temperature alloy is provided. The method shares a pretreatment system for dissolving the iron-nickel-based alloy according to the dependence and commonality of titanium and cobalt in the determination process, and is suitable for the determination of titanium and cobalt contents in the iron-nickel-based alloy with a titanium content of 0.01 to 2.40% and a cobalt content of 0.01 to 3.00%. The determination of titanium and cobalt elements is realized by color development of the titanium ion-diantipyryl methane-ascorbic acid system and the cobalt ion-nitroso red salt-sodium acetate system. The method has the advantages of large determination range, high sensitivity, good stability, high accuracy and strong anti-interference, and provides a basis for the analysis of titanium and cobalt elements in the iron-nickel-based alloy.

[0023] The principle of the detection method provided by the present invention is:

[0024] The present invention adopts diantipyryl methane photometry to determine the titanium in the iron-nickel base alloy. The determination principle is: in an acidic medium, titanium ions (Ti 4+) reacts with the antipyrine group in the diantipyrine methane (DAPM) molecule to form a yellow complex. The color depth of the complex is proportional to the concentration of titanium ions and has a specific absorption wavelength in the visible light region. This coordination reaction is used as the basis for the photometric determination of titanium. The chemical reaction formula is:

[0025] Ti 4+ +n(DAPM)→[Ti(DAPM)n] (4-n)+

[0026] Where n represents the number of complexes between each titanium ion and DAPM molecule, [Ti(DAPM)n] (4-n)+ Indicates the complex ion formed, whose charge and color vary depending on the number of complexes.

[0027] The present invention adopts nitroso red salt photometry to determine the cobalt in the iron-nickel based alloy. The determination principle is: cobalt ion (Co 2+ or Co 3+ ) forms a coordination bond with the R-NO group in the nitroso red salt molecule. The cobalt ion serves as the central ion and the nitroso red salt molecule serves as the ligand to form a colored complex. The color depth of the complex is proportional to the cobalt ion concentration and has a specific absorption wavelength in the visible light region. The coordination reaction of cobalt ions and nitroso red salt (that is, color development reaction) is used as the basis for the photometric determination of cobalt. The chemical reaction formula is:

[0028] Co 2+ +R-NO → [Co(R-NO)2] 2+

[0029] Among them, the cobalt ion and the nitroso red salt molecule (represented by R-NO here) are combined through coordination bonds to form a complex [Co(R-NO)2] 2+ .

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] (1) The present invention adopts aqua regia to dissolve the sample to be tested. In addition to dissolving the sample to be tested, the nitric acid in the aqua regia can also oxidize the phosphate in the mixed acid into a high-valent phosphate in advance when the sulfur-phosphorus acid is subsequently added, thereby preventing the low detection results of cobalt and titanium elements caused by the escape of phosphate into phosphine.

[0032] (2) The present invention uses sulfuric acid and phosphoric acid mixed acid to perform smoke treatment on the sample to be tested, firstly to drive away the excess acid existing due to the addition of aqua regia during the smoke process, and secondly to provide the necessary acidity to make Ti 4+The color development reaction with diantipyryl methane (DAPM) and cobalt ions and nitroso red salt can be carried out, and at the same time, the complexes of titanium or cobalt with sulfate and phosphate (that is, interfering complexes) can be destroyed, so that titanium and cobalt are released in the form of ions, thereby improving the detection accuracy of the two elements. The sulfuric acid in the sulfuric-phosphoric acid mixed acid can remove the inorganic acid (hydrochloric acid and nitric acid) in the mother liquor and improve the determination accuracy of cobalt and titanium elements. However, if too much sulfuric acid is added or the smoking time is too long, it will cause the hydrolysis of titanium and cobalt ions or the formation of insoluble sulfates, affecting the determination results. The phosphoric acid in the mixed acid is a medium-strong acid. When heated until it smokes, it can further destroy the interfering complexes and release titanium and cobalt in the form of ions. At the same time, phosphoric acid can also react with calcium ions (Ca 2+ ), magnesium ion (Mg 2+ ), aluminum ions (Al 3+ ), iron ions (Fe 3+ ), manganese ion (Mn 2+ ) and other metal ions to form insoluble phosphate precipitates such as calcium phosphate, magnesium phosphate, aluminum phosphate, iron phosphate, and manganese phosphate, thereby removing these interfering ions.

[0033] (3) The present invention uses a mixed acid composed of sulfuric acid and phosphoric acid instead of a single acid for fume treatment because if sulfuric acid is added alone for fume treatment, as a strong acid, sulfuric acid will destroy the complex of titanium and ascorbic acid, causing titanium to exist in the solution in the form of ions, affecting the measurement results. Although sulfuric acid is also contained in the mixed acid used in the present invention, compared with pure sulfuric acid, the concentration of sulfuric acid in the mixed acid is low due to water dilution, and the complex of titanium and ascorbic acid will not be destroyed. If phosphoric acid is added alone, the fume process of phosphoric acid is relatively cumbersome and requires strict control of conditions. However, when phosphoric acid is added as a mixed acid, the synergistic effect of sulfuric acid and phosphoric acid can more effectively destroy the complex of titanium or cobalt with other substances, causing titanium and cobalt to be released in the form of ions, and can also remove other impurity ions. At the same time, the subsequent color development reaction conditions are optimized, and the acidity of the mother liquor is adjusted, which is conducive to the color development reaction, further improving the measurement accuracy and sensitivity of titanium and cobalt elements, and making the measurement results more stable and reliable.

[0034] (4) The present invention adds hydrochloric acid solution during the determination of titanium by diantipyryl methane spectrophotometry to adjust the acidity of the mother liquor and destroy the complex between titanium and other substances, so that titanium exists in the form of ions, which is convenient for reacting with diantipyryl methane. Too much hydrochloric acid solution will interfere with the reaction between titanium and diantipyryl methane, while too little hydrochloric acid solution cannot completely destroy the complex between titanium and other substances, resulting in a low titanium element determination result. The main function of the present invention to introduce ascorbic acid is to eliminate the influence of interfering elements such as iron, chromium, and vanadium, especially Fe 3+ Interference. 3+ Interfering ions such as diantipyryl methane will react with diantipyryl methane and affect the determination of titanium. Ascorbic acid needs to be added to reduce Fe 3+However, too much ascorbic acid will compete with titanium ions and affect their complexation with diantipyryl methane. Too little ascorbic acid cannot completely reduce interfering ions such as iron, chromium, and vanadium, resulting in a higher titanium determination result.

[0035] (5) The present invention adds sodium acetate during the determination of cobalt by nitroso red salt spectrophotometry. The main function is to adjust the pH value (pH=5-5.5) of the reaction system of cobalt ions and nitroso red salt, and as a buffer, stabilize the pH value of the reaction system by absorbing or releasing hydrogen ions. Too little sodium acetate cannot effectively adjust the pH value of the reaction system, resulting in incomplete reaction of cobalt ions and nitroso red salt or unstable complex; too much sodium acetate interferes with the formation of the complex of cobalt ions and nitroso red salt reaction, affecting the determination result of cobalt element. Nitric acid is added and boiled during the determination of cobalt by nitroso red salt spectrophotometry to destroy the complex formed by nickel, chromium, copper and nitroso red salt in the precipitated iron-nickel alloy. Too little nitric acid cannot effectively destroy the complex formed by nickel, chromium, copper and nitroso red salt. Too much nitric acid changes the acidity of the reaction system, affects the reaction of cobalt ions and nitroso red salt, and even destroys the complex formed by the reaction of cobalt ions and nitroso red salt, resulting in inaccurate determination result of cobalt element.

[0036] (6) The detection method provided by the present invention is based on the specific color development reaction of diantipyryl methane and titanium and nitroso red salt and cobalt, and has good selectivity for titanium and cobalt, so that it is not interfered by the matrix and spectrum, has good selectivity and stability, is less affected by ambient temperature, has strong anti-interference ability, small error, high sensitivity and accuracy.

[0037] (7) The detection method provided by the present invention simultaneously processes titanium and cobalt in the process of sample dissolution and mother solution preparation, reducing the repeated steps and reagent consumption required for separate determinations, thereby saving detection time and resources, less time consumption, low cost, and more efficient detection means. Although methods such as ICP-OES and ICP-MS can also simultaneously determine multiple elements, when determining the two specific elements of titanium and cobalt, they will be interfered by other coexisting elements, resulting in inaccurate detection results.

[0038] (8) The detection method provided by the present invention comprehensively considers the mutual influence between titanium and cobalt elements, continuously determines titanium and cobalt elements under the same conditions, enhances the comparability of data, and effectively reduces the systematic errors that may occur when determining single elements of titanium or cobalt through comparison and correction, facilitates comprehensive analysis and evaluation of experimental results, and improves the accuracy of determination of titanium and cobalt elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1To determine the absorbance-titanium content standard curve of titanium using different amounts of diantipyrine methane solution, diantipyrine methane solution was added to (A) 5 mL; (B) 10 mL; (C) 15 mL; (D) 20 mL;

[0040] Figure 2 To determine the absorbance-cobalt content standard curve of cobalt using different amounts of nitroso red salt solution, add (A) 10 mL; (B) 20 mL; (C) 30 mL; (D) 40 mL of nitroso red salt solution;

[0041] Figure 3 is the absorbance-titanium content standard curve in Example 1;

[0042] Figure 4 This is the absorbance-cobalt content standard curve in Example 1. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in combination with the embodiments of the specification. In the following description, many specific details are elaborated to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0046] In the following embodiments, the normative references are as follows:

[0047] GB / T 6682-2008 Specifications and test methods for water used in analytical laboratories;

[0048] GB / T 12806-2011 "Laboratory Glassware Single-line Volumetric Flasks";

[0049] GB / T 12808-2015 "Laboratory Glass Instruments - Single Marked Pipette";

[0050] GB / T 12809-2015 "Design and structural principles of laboratory glass instruments and glass measuring vessels";

[0051] GB / T 12810-2021 "Capacity calibration and use of laboratory glass instruments and glass measuring vessels".

[0052] The instruments used in the present invention are all within the calibration period, and their performance meets the technical parameter indicators required by the calibration; the glass containers use Grade A specified in GB / T 12808-2015, GB / T 12809-2015, and GB / T 12806-2011, and the specific usage method refers to the requirements of GB / T 12810.

[0053] The following experiments to determine the optimal amounts of diantipyryl methane solution and nitroso red salt solution and the reagents used in the examples are as follows: water is deionized water or distilled water; hydrochloric acid concentration is 1.19 g / mL; nitric acid concentration is 1.42 g / mL; sulfuric acid concentration is 1.83 g / mL; phosphoric acid concentration is 1.87 g / mL; hydrochloric acid solution (1+1): a hydrochloric acid solution (1+1) obtained by mixing equal volumes of hydrochloric acid having a concentration of 1.19 g / mL and water; sulfuric acid solution (1+3): a sulfuric acid solution (1+3) obtained by mixing sulfuric acid having a concentration of 1.83 g / mL and water in a volume ratio of 1:3; 1.0 mol / L hydrochloric acid solution: take 84.75 mL of concentrated hydrochloric acid having a concentration of 1.19 g / mL, add water to make the volume to 1000 mL, and obtain a 1.0 mol / L hydrochloric acid solution, the 1.0 mol / L The hydrochloric acid solution mentioned in the hydrochloric acid solution is not the hydrochloric acid with a concentration of 1.19g / mL mixed with equal volumes of water as mentioned above, which means that the hydrochloric acid solution is a hydrochloric acid solution with a concentration of 1.0mol / L; ascorbic acid, diantipyryl methane, sodium acetate and nitroso red salt are all analytically pure reagents; titanium is spectrally pure (purchased by the Iron and Steel Research Institute of the National Iron and Steel Materials Testing Center), standard stock solution: 1.0mg / mL; cobalt is spectrally pure (purchased by the Iron and Steel Research Institute of the National Iron and Steel Materials Testing Center), standard stock solution: 1.0mg / mL; titanium standard solution: dilute the titanium standard stock solution to 1mL containing 0.50mg of titanium, and keep the same acidity as the standard stock solution; cobalt standard solution: dilute the cobalt standard stock solution to 1mL containing 0.01mg of cobalt, and keep the same acidity as the standard stock solution.

[0054] The present invention is to determine the optimal amount of diantipyryl methane solution in titanium by diantipyryl methane photometry, and the optimal amount of nitroso red salt solution in cobalt by nitroso red salt photometry. Different amounts of diantipyryl methane solution and nitroso red salt solution are used for absorbance detection, and standard curves are drawn. The method is as follows:

[0055] Determine the optimal dosage of diantipyryl methane solution:

[0056] (1) Add 20 mL of aqua regia to a 150 mL conical flask, then add 40 mL of sulfuric acid (composed of sulfuric acid, phosphoric acid and water in a volume ratio of 3:6:11), heat and evaporate until smoke appears and maintain for 1 min. After cooling, add 40 mL of water and boil at 150°C for 1 min. Then cool to room temperature, pour into a 100 mL volumetric flask, make up to volume, and shake well to obtain the standard curve matrix solution.

[0057] (2) Pipette 0.00, 0.20, 0.40, 0.60, 0.80, and 1.00 mL of 0.50 mg / mL titanium standard stock solution into six 100 mL volumetric flasks, add 10 mL of the standard curve matrix solution to each of the six volumetric flasks, then add 10 mL of hydrochloric acid solution (1+1) and 5 mL of ascorbic acid solution. After standing for 5 min, add 5 mL of diantipyryl methane solution, add water to make up to volume, shake well, and stand for 20 min. Measure the absorbance of the standard solution, and use the mass fraction of titanium as the horizontal axis and the absorbance as the vertical axis to obtain the absorbance-titanium content standard curve.

[0058] The preparation method of the ascorbic acid solution is as follows: weigh 20 g of ascorbic acid, dissolve it in water and then dilute it to 1000 mL; the preparation method of the diantipyrine methane solution is as follows: weigh 50 g of diantipyrine methane, dissolve it in 1.0 mol / L hydrochloric acid solution, and dilute it to 1000 mL with 1.0 mol / L hydrochloric acid solution to obtain a diantipyrine methane solution;

[0059] According to the above steps, experiments were carried out with 10mL, 15mL and 20mL of diantipyrine methane solution. The results are as follows Figure 1 As shown, it can be seen from the absorbance-titanium content standard curve that when the diantipyrine methane solution is 10 mL, the standard curve has the best correlation, with a correlation coefficient of 0.9998. In the following examples, the amount of diantipyrine methane solution used is 10 mL.

[0060] Determine the optimal amount of nitroso red salt solution:

[0061] (1) Add 20 mL of aqua regia to a 150 mL conical flask, then add 40 mL of sulfuric acid (composed of sulfuric acid, phosphoric acid and water in a volume ratio of 3:6:11), heat and evaporate until smoke appears and maintain for 1 min. After cooling, add 40 mL of water and boil at 150°C for 1 min. Then cool to room temperature, pour into a 100 mL volumetric flask, make up to volume, and shake well to obtain the standard curve matrix solution.

[0062] (2) Pipette 0.00, 0.20, 0.40, 0.60, 0.80, and 1.00 mL of 0.01 mg / mL cobalt standard stock solution into 6 100 mL steel volumetric flasks, add 5 mL of standard curve matrix solution into each of the 6 steel volumetric flasks, then add 10 mL of water, 10 mL of sodium acetate solution, and 30 mL of nitroso red salt solution, boil at 150° C. for 1 min, cool for 1 min, add 5 mL of HNO3, and boil again at 150° C. for 1 min, cool to room temperature, add water to make up to volume, shake well, and measure the absorbance of the standard solution. Use the mass fraction of cobalt as the abscissa and the absorbance as the ordinate to obtain an absorbance-cobalt content standard curve;

[0063] The preparation method of sodium acetate solution is as follows: weigh 500g sodium acetate, add water to dissolve and then dilute to 1000mL; the preparation method of nitroso red salt solution is as follows: weigh 3g nitroso red salt, add water to dissolve and then dilute to 1000mL;

[0064] According to the above steps, experiments were carried out with 20mL, 30mL and 40mL of nitroso red salt solution. The results are as follows Figure 2 As shown, it can be seen from the absorbance-cobalt content standard curve that when the nitroso red salt solution is 10 mL, the standard curve correlation is the best. In the following examples, the amount of nitroso red salt solution used is 10 mL.

[0065] In order to keep the reaction system the same and to achieve high accuracy of the detection result when measuring different contents of titanium and cobalt elements, the present invention needs to control the amount of mother liquor pipetted and the mother liquor fixed volume (adding the standard curve matrix solution to keep the acidity consistent) to achieve the measurement of different contents of titanium and cobalt elements. The specific amounts and specifications of the mother liquor pipetted, the mother liquor fixed volume, the standard curve matrix solution volume and the absorption dish when measuring different contents of titanium and cobalt elements are shown in Tables 1 and 2.

[0066] Table 1 The amount of test solution and the specifications of the absorption dish when the method provided by the present invention detects samples with different titanium contents

[0067]

[0068] Table 2 The amount of mother solution and the specifications of the absorption dish when the method provided by the present invention detects samples with different cobalt contents

[0069]

[0070] In order to verify the accuracy of the detection method provided by the present invention, the titanium and cobalt content of different traceable certified metal standards were detected. The specific detection method is shown in Examples 1 to 5.

[0071] Example 1

[0072] (1) Preparation of mother solution and standard curve matrix solution: weigh 0.2000 g of certified metal standard YSBC 11587-2020 and place it in a 150 mL conical flask. Add 20 mL of aqua regia and place the conical flask in a low temperature furnace at 200 °C for 5 min to dissolve the certified metal standard YSBC 11587-2020. Then add 40 mL of sulfuric acid mixed acid (composed of sulfuric acid, phosphoric acid and water in a volume ratio of 3:6:11). Continue heating and evaporating until smoke appears and maintain for 1 min. After cooling, add 40 mL of water and boil at 150 °C for 1 min. After cooling to room temperature, dilute to volume in a 200 mL volumetric flask and shake well for use.

[0073] Add 20 mL of aqua regia to a 150 mL conical flask, then add 40 mL of sulfuric acid and phosphoric acid mixture, heat and evaporate until smoke appears and maintain for 1 min, add 40 mL of water and boil for 1 min after cooling, then cool to room temperature, pour into a 100 mL volumetric flask, make up to volume, shake well, and obtain the standard curve matrix solution;

[0074] (2) Determination of titanium by diantipyrine methane spectrophotometry: Accurately pipette 5.0 mL of the mother solution in two steps (1) and place them in 200 mL volumetric flasks respectively as test solutions, add 15 mL of the standard curve matrix solution, add 10 mL of hydrochloric acid solution (1+1) and 5 mL of 2 wt% ascorbic acid solution to one of the test solutions, let it stand for 5 min, then add 10 mL of 5 wt% diantipyrine methane solution, add water to make up the volume, shake well, and then place it for 20 min as a color developing solution for standby use; add 10 mL of hydrochloric acid solution (1+1) and 5 mL of 2 wt% ascorbic acid solution to the other test solution, add water to make up the volume, shake well, and then place it for 20 min to obtain a blank solution, and measure the absorbance of the color developing solution at a wavelength of 420 nm on a spectrophotometer using the blank solution as a reference;

[0075] The preparation method of the ascorbic acid solution is as follows: weigh 20 g of ascorbic acid, dissolve it in water and then dilute it to 1000 mL; the preparation method of the diantipyrine methane solution is as follows: weigh 50 g of diantipyrine methane, dissolve it in 1.0 mol / L hydrochloric acid solution, and dilute it to 1000 mL with 1.0 mol / L hydrochloric acid solution to obtain a diantipyrine methane solution;

[0076] (4) Determination of cobalt by nitroso red salt photometric method: 4.0 mL of each of the two mother liquors was transferred into 100 mL steel volumetric flasks as test solutions. 10 mL of water, 10 mL of 50 wt% sodium acetate solution and 30 mL of 0.3 wt% nitroso red salt solution were added to one of the test solutions, boiled at 150° C. for 1 min, cooled for 1 min (slightly cooled), and then 5 mL of HNO3 was added. The solution was boiled again at 150° C. for 1 min, then cooled to room temperature, water was added to make up the volume, shaken and allowed to stand for 20 min, and used as a color developing solution for standby use. 5 mL of HNO3, 10 mL of 50 wt% sodium acetate solution and 30 mL of 0.3 wt% nitroso red salt solution were added to the other test solution, water was added to make up the volume, shaken and allowed to stand for 20 min, and used as a blank solution. The absorbance of the color developing solution was measured at a wavelength of 520 nm on a spectrophotometer with the blank solution as a reference.

[0077] The preparation method of sodium acetate solution is as follows: weigh 500g sodium acetate, add water to dissolve and then dilute to 1000mL; the preparation method of nitroso red salt solution is as follows: weigh 3g nitroso red salt, add water to dissolve and then dilute to 1000mL;

[0078] (5) Drawing of standard curve and calculation of element content: 0.00, 0.10, 0.20, 0.30, 0.40, and 0.50 mL of 0.50 mg / mL titanium standard stock solution were respectively transferred into 6 100 mL volumetric flasks. 10 mL of standard curve matrix solution was added to each of the 6 volumetric flasks. Then, 10 mL of hydrochloric acid solution (1+1) and 5 mL of ascorbic acid solution were added. After standing for 5 min, 10 mL of diantipyrine methane solution was added. Water was added to make up the volume, the solution was shaken, and then allowed to stand for 20 min. The absorbance of the standard solution was measured. The mass fraction of titanium was used as the horizontal axis and the absorbance was used as the vertical axis. The standard curve was obtained as shown in the figure. Figure 3 As shown, the standard curve equation is obtained according to formula (1) to calculate the titanium content;

[0079] Take 0.00, 0.20, 0.40, 0.60, 0.80, and 1.00 mL of 0.01 mg / mL cobalt standard stock solution respectively and place them in 6 100 mL steel volumetric flasks. Add 5 mL of standard curve matrix solution to each of the 6 volumetric flasks, then add 10 mL of water, 10 mL of 50 wt% sodium acetate solution, and 30 mL of 0.3 wt% nitroso red salt solution. Boil at 150 ° C for 1 min, cool for 1 min (that is, slightly cool), then add 5 mL of HNO3, boil again at 150 ° C for 1 min, cool to room temperature, add water to make up the volume, shake well, and let stand for 20 min. Measure the absorbance of the standard solution, take the mass fraction of cobalt as the horizontal axis and the absorbance as the vertical axis, and obtain a standard curve, as shown in Figure 2. Figure 4 As shown, the standard curve equation is obtained according to formula (1), and the cobalt content in the sample solution to be tested is calculated;

[0080]

[0081] in:

[0082] —The average value of the six mass concentrations of titanium or cobalt in the titanium or cobalt standard stock solution during the drawing of the standard curve, specifically: The unit is mg / mL;

[0083] —The average absorbance of titanium or cobalt element during the process of drawing the standard curve, specifically:

[0084] x—mass concentration of titanium or cobalt in the test solution, in mg / mL;

[0085] y—absorbance of titanium or cobalt in the test solution;

[0086] The test results of the titanium and cobalt content in the certified metal standard YSBC 11587-2020 in this example are shown in Table 3.

[0087] Example 2

[0088] The difference between this embodiment and embodiment 1 is that the sample is a certified metal standard sample BS 725, and the remaining steps and process parameters are the same as those in embodiment 1. The test results of the titanium and cobalt content in the certified metal standard sample BS 725 in this embodiment are shown in Table 3.

[0089] Example 3

[0090] The difference between this embodiment and embodiment 1 is that the sample is a certified metal standard 23X 08811A, the amount of the two mother solutions in (2) is 10.0 mL, the volume of the standard curve matrix solution added is 10.0 mL, and the remaining steps and process parameters are the same as those in embodiment 1. The results of the detection of the titanium and cobalt content in the certified metal standard 23X 08811A in this embodiment are shown in Table 3.

[0091] Example 4

[0092] The difference between this embodiment and embodiment 1 is that the sample is a certified metal standard sample IARM 328B, and the remaining steps and process parameters are the same as those in embodiment 1. The test results of the titanium and cobalt content in the certified metal standard sample IARM 328B in this embodiment are shown in Table 3.

[0093] Comparative Example 1

[0094] The difference between this comparative example and Example 1 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard YSBC 11587-2020. The test results are shown in Table 3.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 2 is that the content of titanium and cobalt elements in the certified metal standard BS 725 is detected by ICP-AES method. The detection results are shown in Table 3.

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 3 is that the content of titanium and cobalt elements in the certified metal standard 23X 08811A is detected by ICP-AES method. The detection results are shown in Table 3.

[0099] Comparative Example 4

[0100] The difference between this comparative example and Example 4 is that the content of titanium and cobalt elements in the certified metal standard IARM 328B is detected by ICP-AES method. The detection results are shown in Table 3.

[0101] Table 3 Test results of titanium and cobalt content in certified metal standard samples of Examples 1 to 4 and Comparative Examples 1 to 4

[0102]

[0103] From the data in Table 3, it can be seen that when the sample weight is 0.2000g, the titanium content in the certified metal standard is 0.54-1.53%, and the cobalt content is 0.020-0.082%, the contents of titanium and cobalt elements in the sample can be detected, and are close to the standard values ​​of the metal standard, indicating that the error of the detection method provided by the present invention is very small, and it has high accuracy and reliability. Compared with the ICP-AES method, the results of the titanium and cobalt content of the detection method provided by the present invention are obviously closer to the standard values ​​of the metal standard, indicating that the accuracy is higher than that of the ICP-AES method.

[0104] The detection method provided by the present invention is used to detect the titanium and cobalt content in different iron-nickel based high temperature alloys (numbered 1 to 7). For comparison, the titanium and cobalt content in the iron-nickel based high temperature alloys (numbered 1 to 7) in each of the following embodiments is also detected by ICP-AES.

[0105] Example 5

[0106] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 1, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 1 of this embodiment are shown in Table 4.

[0107] Example 6

[0108] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 2, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 2 of this embodiment are shown in Table 4.

[0109] Example 7

[0110] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 3, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 3 of this embodiment are shown in Table 4.

[0111] Example 8

[0112] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 4, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 4 of this embodiment are shown in Table 4.

[0113] Example 9

[0114] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 5, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 5 of this embodiment are shown in Table 4.

[0115] Example 10

[0116] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 6, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 6 of this embodiment are shown in Table 4.

[0117] Embodiment 11

[0118] The difference between this embodiment and embodiment 1 is that the sample is an iron-nickel based high temperature alloy 7, and the remaining steps and process parameters are the same as those of embodiment 1. The test results of the titanium and cobalt content in the iron-nickel based high temperature alloy 6 of this embodiment are shown in Table 4.

[0119] Comparative Example 5

[0120] The difference between this comparative example and Example 5 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 1. The test results are shown in Table 3.

[0121] Comparative Example 6

[0122] The difference between this comparative example and Example 6 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 2. The test results are shown in Table 4.

[0123] Comparative Example 7

[0124] The difference between this comparative example and Example 7 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 3. The test results are shown in Table 4.

[0125] Comparative Example 8

[0126] The difference between this comparative example and Example 8 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 4. The test results are shown in Table 4.

[0127] Comparative Example 9

[0128] The difference between this comparative example and Example 9 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 5. The test results are shown in Table 4.

[0129] Comparative Example 10

[0130] The difference between this comparative example and Example 10 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel-based high-temperature alloy 6. The test results are shown in Table 4.

[0131] Comparative Example 11

[0132] The difference between this comparative example and Example 11 is that the ICP-AES method is used to detect the content of titanium and cobalt elements in the certified metal standard iron-nickel based high temperature alloy 7. The test results are shown in Table 4.

[0133] Example 12

[0134] The difference between this embodiment and embodiment 5 is that, based on the existing titanium and cobalt content in the iron-nickel based high-temperature alloy 1, the titanium sample is spiked with 0.5% and the cobalt sample is spiked with 0.05%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment is the same as the steps and process parameters in embodiment 5. The detection results are shown in Table 5.

[0135] Embodiment 13

[0136] The difference between this embodiment and embodiment 6 is that, based on the titanium and cobalt content in the iron-nickel based high-temperature alloy 2, the titanium sample is spiked with 0.5% and the cobalt sample is spiked with 0.05%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment has the same steps and process parameters as those in embodiment 6. The detection results are shown in Table 5.

[0137] Embodiment 14

[0138] The difference between this embodiment and embodiment 7 is that, based on the titanium and cobalt content in the iron-nickel based high-temperature alloy 3, the titanium sample is spiked with 0.5% and the cobalt sample is spiked with 0.05%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment is the same as the steps and process parameters in embodiment 7. The detection results are shown in Table 5.

[0139] Embodiment 15

[0140] The difference between this embodiment and embodiment 5 is that, based on the titanium and cobalt content in the iron-nickel based high-temperature alloy 1, the titanium sample is spiked with 1.0% and the cobalt sample is spiked with 0.1%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment has the same steps and process parameters as those in embodiment 5. The detection results are shown in Table 5.

[0141] Example 16

[0142] The difference between this embodiment and embodiment 6 is that, based on the titanium and cobalt content in the iron-nickel based high-temperature alloy 2, the titanium sample is spiked with 1.0% and the cobalt sample is spiked with 0.1%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment is the same as the steps and process parameters in embodiment 5. The detection results are shown in Table 5.

[0143] Embodiment 17

[0144] The difference between this embodiment and embodiment 7 is that, based on the titanium and cobalt content in the iron-nickel based high-temperature alloy 3, the titanium sample is spiked with 1.0% and the cobalt sample is spiked with 0.1%, and the content of titanium and cobalt elements is detected. The detection method of this embodiment is the same as the steps and process parameters in the embodiment. The detection results are shown in Table 5.

[0145] Table 4 Detection results of titanium and cobalt content in iron-nickel based high temperature alloys of Examples 5 to 11 and Comparative Examples 5 to 11

[0146]

[0147]

[0148] Table 5 Results of the precision determination of titanium and cobalt elements in the Fe-Ni-based superalloys of Examples 12 to 17

[0149]

[0150] According to the data in Table 4 and Table 5, by comparing Examples 5 to 6 with Examples 12 to 14 and Examples 15 to 17, it can be seen that after the titanium and cobalt elements in the iron-nickel-based high-temperature alloy samples 1, 2 and 3 are spiked, the actual content detection values ​​of the two elements are close to the sum of the actual detection value before the spike and the spiked amount, indicating that the detection method provided by the present invention has high accuracy and reliability.

[0151] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for detecting the content of titanium and cobalt elements in a precipitated iron-nickel-based high-temperature alloy, characterized in that: include: (1) Preparation of mother solution and standard curve matrix solution: Weigh 0.2000 g of the sample to be tested and place it in a conical flask, add aqua regia to dissolve the sample to be tested, then add sulfuric acid and phosphoric acid mixture, heat and evaporate until smoking, add 40 mL of water to boil after cooling, then cool to room temperature, pour into a volumetric flask, make up to volume, shake well to obtain a mother solution, and then perform a blank experiment without adding the sample to be tested to obtain a standard curve matrix solution; (2) Determination of titanium by diantipyryl methane spectrophotometry: Two portions of the mother liquor were transferred into two volumetric flasks respectively as test solutions. 10 mL of hydrochloric acid solution and 5 mL of ascorbic acid solution were added to one portion of the test solution. After standing, 10 mL of diantipyryl methane solution was added, water was added to make up the volume, and the solution was allowed to stand for a period of time as a color developing solution. 10 mL of hydrochloric acid solution and 5 mL of ascorbic acid solution were added to the other portion of the test solution. Water was added to make up the volume, and the solution was allowed to stand for a period of time after being shaken to obtain a blank solution. The absorbance of the color developing solution was measured at a wavelength of 380 nm or 420 nm using a spectrophotometer with the blank solution as a reference. (3) Determination of cobalt by nitroso red salt photometric method: Pipette two portions of the mother liquor and place them in steel volumetric flasks respectively as the test solution. Add 10 mL of water, 10 mL of sodium acetate solution and 30 mL of nitroso red salt solution to one portion of the test solution, boil it, cool it for 1 min, add 5 mL of HNO3, boil it again, cool it to room temperature, add water to make up the volume, shake it well and let it stand for a while as the color developing solution. Add 5 mL of HNO3, 10 mL of sodium acetate solution and 30 mL of nitroso red salt solution to the other portion of the test solution, add water to make up the volume, shake it well and let it stand for a while as the blank solution. Measure the absorbance of the color developing solution at a wavelength of 520 nm on a spectrophotometer with the blank solution as a reference. (4) Drawing of standard curve and calculation of element content: Standard curves were drawn using titanium standard stock solution and cobalt standard stock solution, respectively, and the contents of titanium and cobalt were calculated.

2. The detection method according to claim 1, characterized in that: (1) The medium sulfuric acid and phosphoric acid mixture is composed of sulfuric acid, phosphoric acid and water in a volume ratio of 3:6:

11.

3. The detection method according to claim 1, characterized in that: (1) The amount of aqua regia used is 20 mL; the amount of sulfuric acid and phosphoric acid mixed used is 40 mL.

4. The detection method according to claim 1, characterized in that: (1) The dissolution temperature is 180-220°C, the time is 5 minutes, and the smoking time is 1 minute.

5. The detection method according to claim 1, characterized in that: (2) The ascorbic acid solution is prepared by weighing 20 g of ascorbic acid, dissolving it in water, and then diluting the volume to 1000 mL to obtain an ascorbic acid solution; the diantipyrine methane solution is prepared by weighing 50 g of diantipyrine methane, dissolving it in 1.0 mol / L hydrochloric acid solution, and then diluting the volume to 1000 mL with 1.0 mol / L hydrochloric acid solution to obtain a diantipyrine methane solution.

6. The detection method according to claim 1, characterized in that: (2) The two mother liquors are pipetted in amounts of 10.0 mL or 5.0 mL respectively; the two volumetric flasks are of specifications of 100 mL or 200 mL respectively.

7. The detection method according to claim 1, characterized in that: In (2) and (3), the colorimetric solution and the blank solution are kept aside for 10 to 20 minutes after being shaken.

8. The detection method according to claim 1, characterized in that: (3) The preparation method of sodium acetate solution is as follows: weigh 500 g of sodium acetate, add water to dissolve it, and then dilute it to 1000 mL to obtain sodium acetate solution; the preparation method of nitroso red salt solution is as follows: weigh 3 g of nitroso red salt, add water to dissolve it, and then dilute it to 1000 mL to obtain nitroso red salt solution.

9. The detection method according to claim 1, characterized in that: (3) The two mother liquors are both 4.0 mL or 2.0 mL; the two steel volumetric flasks are both 100 mL or 200 mL.

10. The detection method according to claim 1, characterized in that: (3) The medium boiling and re-boiling time are both 1 to 2 minutes.

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