A method for simultaneously determining oxygen and nitrogen contents in titanium materials

Abstract

The present invention provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material, the method comprising the following steps: (1) using a multi-point calibration method to independently establish an oxygen standard curve and a nitrogen standard curve; (2) using a nickel material to wrap the titanium material to be tested to form an inclusion; (3) placing the inclusion obtained in step (2) in a graphite container, passing an inert gas and heating the molten inclusion to release carbon monoxide, carbon dioxide and nitrogen; (4) detecting the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium material according to the oxygen standard curve obtained in step (1); (5) detecting the nitrogen obtained in step (3), and determining the nitrogen content in the titanium material according to the nitrogen standard curve obtained in step (1); wherein step (4) and step (5) are performed simultaneously. The method provided by the present invention is particularly suitable for determining high-content oxygen and nitrogen elements in titanium materials, and the analysis method is accurate and reliable, and the analysis results are stable.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and testing, and relates to a method for simultaneously determining the contents of oxygen and nitrogen, and in particular to a method for simultaneously determining high-content oxygen and nitrogen elements in titanium materials. Background Art

[0002] Titanium material is one of the most popular new materials currently being researched. Titanium alloys, among which, can be used as aircraft engine and fuselage materials, as well as automobile valve rocker arms and other materials because of their advantages such as light weight, high specific strength, wear resistance, combustion resistance, oxidation resistance, and excellent high-temperature mechanical properties. They also have good application prospects in biomedicine, automotive industry and other fields.

[0003] Due to the high solubility of oxygen and nitrogen in the preparation process of titanium materials, they have become mandatory inspection items for titanium materials. Generally, for the determination of oxygen and nitrogen content in titanium materials, the instrumental method can be carried out in accordance with GB / T 4698.7, but the determination range of oxygen content in this method is 0.01wt%-0.50wt%, and the determination range of nitrogen content is 0.003wt%-0.11wt%, which cannot be applied to the determination of oxygen and nitrogen content exceeding this range. In addition, due to the backward equipment, cumbersome operation and long test cycle of the chemical method, it is difficult to meet the needs of modern industrial production.

[0004] For example, in the preparation of titanium coatings for surgical implants, oxygen and nitrogen are inevitably added during the plasma spraying process. ISO:13179-1:2014 stipulates that oxygen ≤ 10wt% and nitrogen ≤ 5wt%; in addition, the oxygen and nitrogen content in titanium sintering and 3D printing samples also exceeds the measurement range of conventional analysis methods. However, for samples with such high oxygen and nitrogen content, there is currently neither an accurate analysis method nor a standard sample with similar content. If conventional calibration methods are used directly, the measurement results will be more biased.

[0005] CN 109342500A discloses a method for simultaneously determining the contents of oxygen, nitrogen and hydrogen in a titanium alloy, the method comprising: placing the titanium alloy in an oxygen, nitrogen and hydrogen analyzer based on an inert gas melting-infrared absorption and / or thermal conductivity method, using metal nickel as a flux, and conducting the determination by a two-stage heating method, wherein the first stage heating temperature is 1050°C-1550°C, and the second stage heating temperature is 2700°C-3000°C; wherein the hydrogen content in the titanium alloy is 0.030%-4.1% (w / w). Although the invention eliminates the interference of high hydrogen content on nitrogen determination and realizes the simultaneous determination of the three elements, it is still not applicable to the analysis and determination of titanium materials with high oxygen and nitrogen contents.

[0006] CN 106525757A discloses a method for determining trace oxygen and nitrogen elements in alloy steel, including step 1: preparing test conditions; step 2: preparing samples; step 3: blank test; step 4: calibrating an oxygen and nitrogen analyzer; 4.1: calibrating using standard substances for oxygen and nitrogen content in steel; 4.2: determining calibration by measuring standard substances for oxygen and nitrogen content in steel; step 5: determining trace oxygen and nitrogen content in the sample. However, the invention is only applicable to the determination of trace oxygen and nitrogen elements, has a limited measurement range, and also has the problem of being unable to accurately determine high-content oxygen and nitrogen elements.

[0007] It can be seen that how to provide a method for simultaneously determining the oxygen and nitrogen content in titanium materials, which is particularly suitable for the determination of high-content oxygen and nitrogen elements, and the analysis method is accurate and reliable, the analysis results are stable, and meet the actual production needs, has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for simultaneously determining the oxygen and nitrogen contents in titanium materials. The method is particularly suitable for the determination of high contents of oxygen and nitrogen elements in titanium materials, and the analysis method is accurate and reliable, and the analysis results are stable.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material, the method comprising the following steps:

[0011] (1) Using a multi-point calibration method, an oxygen standard curve and a nitrogen standard curve are independently established;

[0012] (2) using a nickel material to wrap the titanium material to be tested to form an inclusion;

[0013] (3) placing the inclusion obtained in step (2) in a graphite container, introducing an inert gas and heating the melted inclusion to release carbon monoxide, carbon dioxide and nitrogen;

[0014] (4) detecting the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium material according to the oxygen standard curve obtained in step (1);

[0015] (5) Detecting the nitrogen obtained in step (3) and determining the nitrogen content in the titanium material based on the nitrogen standard curve obtained in step (1).

[0016] Wherein, step (4) and step (5) are performed simultaneously.

[0017] The present invention is based on an instrumental method. A multi-point calibration method is firstly adopted to independently establish an oxygen standard curve and a nitrogen standard curve. Then, the weight of the sample of the titanium material to be measured is reduced so that the oxygen and nitrogen mass of the titanium material is within the range of the standard curve. Thus, the determination of high-content oxygen and nitrogen elements in the titanium material is realized, the accuracy and stability of the determination result are improved, and the problem of large deviation of the measurement result obtained by the conventional calibration method is overcome.

[0018] In the process of establishing the oxygen standard curve and the nitrogen standard curve, the present invention uses a nickel material to wrap the titanium-based material (oxygen standard sample) to form an inclusion body; and for the steel-based material (nitrogen standard sample), no auxiliary solvent needs to be added during melting, and the steel-based material can be directly analyzed.

[0019] In the present invention, the oxygen content of the titanium material to be tested in step (2) is 1-3wt%, for example, it can be 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt% or 3wt%, but is not limited to the listed values, and other unlisted numerical ranges within this numerical range are also applicable.

[0020] In the present invention, the nitrogen content of the titanium material to be tested in step (2) is 0.5-1.5wt%, for example, it can be 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt% or 1.5wt%, but is not limited to the listed values, and other unlisted numerical ranges within this numerical range are also applicable.

[0021] The method provided by the present invention is carried out in a conventional oxygen and nitrogen analyzer. As long as it can achieve the determination of the oxygen and nitrogen contents in the titanium material, there is no particular limitation on the specific model of the oxygen and nitrogen analyzer. For example, the ONH836 high-temperature oxygen and nitrogen analyzer produced by LECO can be used.

[0022] Preferably, the method for establishing the oxygen standard curve in step (1) is: selecting at least 3 first standard samples with different oxygen contents, analyzing the oxygen content of each first standard sample at least 3 times, taking the average value and establishing the oxygen standard curve using a multi-point calibration procedure.

[0023] Preferably, the correlation coefficient R of the oxygen standard curve in step (1) is 2 ≥0.99, for example, it can be 0.99, 0.995 or 0.999, but is not limited to the listed values, and other unlisted value ranges within the numerical range are also applicable.

[0024] Preferably, the first standard sample is a titanium-based standard sample.

[0025] In the present invention, the oxygen content of the titanium-based standard sample is within the measurement range of a conventional oxygen-nitrogen analyzer. As long as the accurate determination of the oxygen content in the titanium material to be measured can be achieved, the specific type of the titanium-based standard sample is not particularly limited. For example, standard samples of model LECO 502-891, LECO 502-888, LECO 502-867 or ALFA AR641 can be used.

[0026] Preferably, the oxygen standard curve is subjected to a first accuracy check after being established.

[0027] Preferably, the specific process of the first accuracy test is: determine the first standard sample of the intermediate oxygen content according to the oxygen standard curve, when the analysis result is within the uncertainty range, it means that the accuracy of the oxygen standard curve is good, otherwise, correction processing is performed.

[0028] In the present invention, the first standard sample with an intermediate oxygen content is specifically a first standard sample with an oxygen content in the range of 0.1-0.5wt% and a distance from the intermediate value of 0.3wt% by no more than 0.1wt%.

[0029] Preferably, the method for establishing the nitrogen standard curve in step (1) is: selecting at least 3 second standard samples with different nitrogen contents, analyzing the nitrogen content of each second standard sample at least 3 times, taking the average value and establishing the nitrogen standard curve using a multi-point calibration procedure.

[0030] Preferably, the correlation coefficient R of the nitrogen standard curve in step (1) is 2 ≥0.99, for example, it can be 0.99, 0.995 or 0.999, but is not limited to the listed values, and other unlisted value ranges within the numerical range are also applicable.

[0031] Preferably, the second standard sample is a steel-based standard sample.

[0032] In the present invention, the nitrogen content of the steel-based standard sample is within the measurement range of a conventional oxygen-nitrogen analyzer. As long as the nitrogen content in the titanium material to be measured can be accurately determined, the specific type of the steel-based standard sample is not particularly limited. For example, standard samples with models YSBC 11936-2012, GBW(E)020089, YSBC 11936-2012 or No. 68-2-1 can be used.

[0033] In the present invention, the nitrogen content and the adjustment area in the titanium material to be tested are within the linear range of the steel-based standard sample, which is one order of magnitude higher than the titanium-based standard sample and exceeds its quantitative range. Therefore, the present invention selects the steel-based standard sample as the second standard sample to calculate the nitrogen content in the titanium material to be tested.

[0034] Preferably, the nitrogen standard curve is subjected to a second accuracy test after being established.

[0035] Preferably, the specific process of the second accuracy test is: determine the second standard sample of the intermediate nitrogen content according to the nitrogen standard curve. When the analysis result is within the uncertainty range, it means that the accuracy of the nitrogen standard curve is good, otherwise, correction processing is performed.

[0036] In the present invention, the second standard sample with an intermediate nitrogen content is specifically a second standard sample with a nitrogen content in the range of 0.05-0.3wt% and a distance from the intermediate value of 0.175wt% by no more than 0.1wt%.

[0037] Preferably, the nickel material in step (2) comprises any one of a nickel basket, a nickel capsule, a nickel foil or a nickel foil cup.

[0038] Preferably, the titanium material to be tested in step (2) includes titanium element or titanium alloy.

[0039] Preferably, the mass ratio of the nickel material to the titanium material to be tested in step (2) is (7-17):1, for example, it can be 7:1, 8:1, 10:1, 12:1, 14:1, 16:1 or 17:1, but is not limited to the listed values, and other unlisted numerical ranges within this numerical range are also applicable.

[0040] In the present invention, the nickel material in step (2) acts as a nickel co-solvent in the subsequent heating and melting process, ensuring the full release of oxygen and nitrogen elements in the titanium material to be tested. The mass ratio of the nickel material to the titanium material to be tested has a significant effect on the full release of nitrogen and oxygen.

[0041] Preferably, the mass of the titanium material to be tested in step (2) is ≤87 mg, for example, it can be 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg or 87 mg, but is not limited to the listed values, and other unlisted numerical ranges within this numerical range are also applicable.

[0042] In the present invention, the mass of the titanium material to be tested has a significant impact on the test results. When the mass of the titanium material to be tested is higher than 87 mg, the content of gas elements (oxygen, nitrogen, hydrogen and other elements) in the sample is relatively high, resulting in a large amount of gas being released instantly during heating and melting, forming a bulge at the crucible mouth, which hinders the release of oxygen and nitrogen elements, and thus leads to a low measurement result.

[0043] Preferably, the graphite container in step (3) comprises a graphite crucible.

[0044] In the present invention, the graphite container in step (3) not only serves as a resistor for carbon and can generate sufficient heat to melt the sample after current is passed, but also the oxygen in the titanium material undergoes an oxidation reaction with the carbon in the graphite container to generate carbon monoxide, and the resulting carbon monoxide reacts with the hot copper oxide in the oxygen-nitrogen analyzer to generate carbon dioxide, thereby achieving full release of the oxygen element in the titanium material.

[0045] Preferably, the inert gas in step (3) comprises helium or argon.

[0046] Preferably, the heating and melting temperature in step (3) is 2200-2300°C, for example, it can be 2200°C, 2210°C, 2220°C, 2230°C, 2240°C, 2250°C, 2260°C, 2270°C, 2280°C, 2290°C or 2300°C, but is not limited to the listed values, and other unlisted numerical ranges within this numerical range are also applicable.

[0047] Preferably, in step (3), the heating and melting is performed until oxygen and nitrogen elements in the titanium material are completely released.

[0048] Preferably, the detection in step (4) is performed using an infrared detector.

[0049] Preferably, the detection in step (5) is performed using a thermal conductivity detector.

[0050] As a preferred technical solution of the present invention, the method comprises the following steps:

[0051] (1) The oxygen standard curve and the nitrogen standard curve are independently established using the multi-point calibration method. The specific process is as follows:

[0052] (a) Select at least three first standard samples with different oxygen contents, analyze the oxygen content of each first standard sample at least three times, take the average value and use the multi-point calibration procedure to establish the correlation coefficient R 2 ≥0.99 oxygen standard curve; a first standard sample of intermediate oxygen content is measured according to the oxygen standard curve, when the analysis result is within the uncertainty range, it means that the accuracy of the oxygen standard curve is good, otherwise it is corrected; the first standard sample is a titanium-based standard sample;

[0053] (b) Select at least three second standard samples with different nitrogen contents, analyze the nitrogen content of each second standard sample at least three times, take the average value and use the multi-point calibration procedure to establish the correlation coefficient R 2 ≥0.99 nitrogen standard curve; a second standard sample of intermediate nitrogen content is determined according to the nitrogen standard curve. When the analysis result is within the uncertainty range, it indicates that the accuracy of the nitrogen standard curve is good, otherwise a correction is performed; the second standard sample is a steel-based standard sample;

[0054] (2) using a nickel material to wrap the titanium material to be tested in a mass ratio of (7-17):1 to form an inclusion; the nickel material comprises any one of a nickel basket, a nickel capsule, a nickel foil or a nickel foil cup; the titanium material to be tested comprises a single titanium substance or a titanium alloy, and the mass of the titanium material to be tested is ≤87 mg;

[0055] (3) placing the inclusion obtained in step (2) in a graphite crucible, introducing helium or argon gas and heating the inclusion at 2200-2300° C. to melt the inclusion until the oxygen and nitrogen elements in the titanium material are completely released in the form of carbon monoxide, carbon dioxide and nitrogen respectively;

[0056] (4) using an infrared detector to detect the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium material according to the oxygen standard curve obtained in step (1);

[0057] (5) Using a thermal conductivity detector to detect the nitrogen obtained in step (3), and determining the nitrogen content in the titanium material based on the nitrogen standard curve obtained in step (1).

[0058] Wherein, step (4) and step (5) are performed simultaneously.

[0059] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] (1) The present invention is based on an instrumental method. A multi-point calibration method is first used to independently establish an oxygen standard curve and a nitrogen standard curve. Then, the weight of the titanium material to be measured is reduced to less than 87 mg, so that the oxygen and nitrogen mass of the titanium material is within the range of the standard curve. First, the mass of the element to be measured is calculated according to the weight of the standard sample. Then, a calibration curve is established with the oxygen / nitrogen mass as the horizontal coordinate and the response area as the vertical coordinate, ensuring that the oxygen / nitrogen mass of the sample to be measured is close to the oxygen / nitrogen mass of the standard sample, thereby maximizing the measurement accuracy.

[0062] (2) The method provided by the present invention increases the measurement range of oxygen content to 1-5wt%, and the measurement range of nitrogen content to 0.5-5wt%, thereby improving the accuracy and stability of the measurement results and overcoming the problem of large deviation in the measurement results obtained by conventional calibration methods. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0064] Example 1

[0065] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method uses an ONH836 high-temperature nitrogen and oxygen analyzer produced by LECO. The oxygen detection range of this analyzer is: 0.00005mg / g-50mg / g, and the nitrogen detection range is 0.00005mg / g-30mg / g; the working conditions are: degassing power 6000W, degassing time 20s, analysis power 5500W, oxygen analysis time 60s, nitrogen analysis time 60s, double degassing, flow rate 450mL / min, and inlet pressure 22psi.

[0066] In this embodiment, the method comprises the following steps:

[0067] (1) The oxygen standard curve and the nitrogen standard curve are independently established using the multi-point calibration method. The specific process is as follows:

[0068] (a) Selecting four first standard samples with different oxygen contents as shown in Table 1, analyzing the oxygen content of each first standard sample three times, taking the average value, and establishing an oxygen standard curve using a multi-point calibration procedure as shown in Formula 1; determining the first standard sample with an intermediate oxygen content according to the oxygen standard curve, the analysis result is within the range of uncertainty, indicating that the accuracy of the oxygen standard curve is good;

[0069] (b) Select 4 second standard samples with different nitrogen contents as shown in Table 2, analyze the nitrogen content of each second standard sample 3 times, take the average value, and establish a nitrogen standard curve using a multi-point calibration procedure as shown in Formula 2; Determine the second standard sample with intermediate nitrogen content according to the nitrogen standard curve, and the analysis result is within the range of uncertainty, indicating that the accuracy of the nitrogen standard curve is good;

[0070] (2) Use a nickel basket to wrap 30 mg of titanium alloy at a mass ratio of 17:1 to form an inclusion. In order to improve the accuracy of the sample measurement, it is necessary to ensure that the oxygen element mass of the standard sample and the sample (note: not the sample mass) is as close as possible;

[0071] (3) placing the inclusion obtained in step (2) in a graphite crucible, introducing helium gas and heating the inclusion at 2250° C. to melt the inclusion until the oxygen and nitrogen elements in the titanium alloy are completely released in the form of carbon monoxide, carbon dioxide and nitrogen respectively;

[0072] (4) using an infrared detector to detect the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium alloy according to the oxygen standard curve of formula 1;

[0073] (5) Using a thermal conductivity detector to detect the nitrogen obtained in step (3), and determining the nitrogen content in the titanium alloy according to the nitrogen standard curve of formula 2.

[0074] Wherein, step (4) and step (5) are performed simultaneously.

[0075] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.64wt%, and the nitrogen content was 1.11wt%.

[0076] Table 1

[0077]

[0078] Oxygen standard curve: Y = 1.01791404X-0.00001586 (1)

[0079] Correlation coefficient R 2 =0.9994.

[0080] Table 2

[0081]

[0082]

[0083] Nitrogen standard curve: Y = 1.10000284X-0.00000431 (2)

[0084] Correlation coefficient R 2 =0.9997.

[0085] Example 2

[0086] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method uses an ONH836 high-temperature nitrogen and oxygen analyzer produced by LECO. The oxygen detection range of this analyzer is: 0.00005mg / g-50mg / g, and the nitrogen detection range is 0.00005mg / g-30mg / g; the working conditions are: degassing power 6000W, degassing time 20s, analysis power 5500W, oxygen analysis time 60s, nitrogen analysis time 60s, double degassing, flow rate 450mL / min, and inlet pressure 22psi.

[0087] In this embodiment, the method comprises the following steps:

[0088] (1) The oxygen standard curve and the nitrogen standard curve are independently established using the multi-point calibration method. The specific process is as follows:

[0089] (a) Three first standard samples with different oxygen contents were selected as shown in Table 3. The oxygen content of each first standard sample was analyzed three times. After taking the average value, an oxygen standard curve was established using a multi-point calibration procedure as shown in Formula 3. The first standard sample with an intermediate oxygen content was measured according to the oxygen standard curve. The analysis result was within the range of uncertainty, indicating that the accuracy of the oxygen standard curve was good.

[0090] (b) The method and results of establishing the nitrogen standard curve in this embodiment are the same as those in Example 1, so they are not described in detail here;

[0091] (2) 30 mg of titanium alloy is wrapped in a nickel capsule at a mass ratio of 13:1 to form an inclusion. In order to improve the accuracy of the sample measurement, the oxygen mass of the standard sample and the sample (note: not the sample mass) must be as close as possible;

[0092] (3) placing the inclusion obtained in step (2) in a graphite crucible, introducing argon gas and heating the inclusion at 2300° C. to melt the inclusion until the oxygen and nitrogen elements in the titanium alloy are completely released in the form of carbon monoxide, carbon dioxide and nitrogen respectively;

[0093] (4) using an infrared detector to detect the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium alloy according to the oxygen standard curve of formula 3;

[0094] (5) Using a thermal conductivity detector to detect the nitrogen obtained in step (3), and determining the nitrogen content in the titanium alloy according to the nitrogen standard curve of formula 2.

[0095] Wherein, step (4) and step (5) are performed simultaneously.

[0096] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.68wt%, and the nitrogen content was 1.10wt%.

[0097] Table 3

[0098]

[0099]

[0100] Oxygen standard curve: Y = 1.00151014X-0.00001521 (3)

[0101] Correlation coefficient R 2 =0.9991.

[0102] Example 3

[0103] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method uses an ONH836 high-temperature nitrogen and oxygen analyzer produced by LECO. The oxygen detection range of this analyzer is: 0.00005mg / g-50mg / g, and the nitrogen detection range is 0.00005mg / g-30mg / g; the working conditions are: degassing power 6000W, degassing time 20s, analysis power 5500W, oxygen analysis time 60s, nitrogen analysis time 60s, double degassing, flow rate 450mL / min, and inlet pressure 22psi.

[0104] In this embodiment, the method comprises the following steps:

[0105] (1) The oxygen standard curve and the nitrogen standard curve are independently established using the multi-point calibration method. The specific process is as follows:

[0106] (a) Three first standard samples with different oxygen contents were selected as shown in Table 4. The oxygen content of each first standard sample was analyzed three times. After taking the average value, an oxygen standard curve was established using a multi-point calibration procedure as shown in Formula 4. The first standard sample with an intermediate oxygen content was measured according to the oxygen standard curve. The analysis result was within the range of uncertainty, indicating that the accuracy of the oxygen standard curve was good.

[0107] (b) The method and results of establishing the nitrogen standard curve in this embodiment are the same as those in Example 1, so they are not described in detail here;

[0108] (2) 30 mg of titanium alloy is wrapped in a nickel capsule at a mass ratio of 8:1 to form an inclusion. In order to improve the accuracy of the sample measurement, the oxygen mass of the standard sample and the sample (note: not the sample mass) must be as close as possible;

[0109] (3) placing the inclusion obtained in step (2) in a graphite crucible, introducing helium gas and heating the inclusion at 2200° C. to melt the inclusion until the oxygen and nitrogen elements in the titanium alloy are completely released in the form of carbon monoxide, carbon dioxide and nitrogen respectively;

[0110] (4) using an infrared detector to detect the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium alloy according to the oxygen standard curve of formula 4;

[0111] (5) Using a thermal conductivity detector to detect the nitrogen obtained in step (3), and determining the nitrogen content in the titanium alloy according to the nitrogen standard curve of formula 2.

[0112] Wherein, step (4) and step (5) are performed simultaneously.

[0113] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.66wt%, and the nitrogen content was 1.11wt%.

[0114] Table 4

[0115]

[0116] Oxygen standard curve: Y = 1.02009680X-0.00002291 (4)

[0117] Correlation coefficient R 2 =0.9984.

[0118] Example 4

[0119] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method is the same as that in Example 1 except that the mass of the titanium alloy sample in step (2) is changed to 28 mg, and therefore will not be described in detail here.

[0120] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.74wt%, and the nitrogen content was 1.11wt%.

[0121] Example 5

[0122] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method is the same as that in Example 1 except that the mass of the titanium alloy sample in step (2) is changed to 58 mg, and therefore will not be described in detail here.

[0123] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.78wt%, and the nitrogen content was 1.08wt%.

[0124] Example 6

[0125] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method is the same as that in Example 1 except that the mass of the titanium alloy sample in step (2) is changed to 87 mg, and therefore will not be described in detail here.

[0126] In this embodiment, the oxygen content of the titanium alloy sample measured was 2.77wt%, and the nitrogen content was 1.05wt%.

[0127] Example 7

[0128] This embodiment provides a method for simultaneously determining the oxygen and nitrogen contents in a titanium material. The method is the same as that in Embodiment 1 except that the mass of the titanium alloy sample in step (2) is changed to 100 mg, and therefore will not be described in detail here.

[0129] In this embodiment, the oxygen content of the titanium alloy sample measured was 1.79wt%, and the nitrogen content was 0.214wt%.

[0130] Compared with Example 1, in this embodiment, since the sample weight of the titanium alloy is too high, the content of gas elements (oxygen, nitrogen, hydrogen and other elements) in the sample is relatively high, resulting in a large amount of gas being released instantly during heating and melting, forming a bulge at the crucible mouth, hindering the release of oxygen and nitrogen elements, and thus causing low measurement results.

[0131] It can be seen that the present invention is based on the instrumental method, firstly adopts the multi-point calibration method to independently establish the oxygen standard curve and the nitrogen standard curve, and then reduces the sample weight of the titanium material to be measured to less than 87 mg, so that the oxygen and nitrogen element mass of the titanium material is within the range of the standard curve; firstly, the mass of the element to be measured is calculated according to the weight of the standard sample, and then the calibration curve is established with the oxygen / nitrogen element mass as the horizontal coordinate and the response area as the vertical coordinate, ensuring that the oxygen / nitrogen element mass of the sample to be measured is similar to the oxygen / nitrogen element mass of the standard sample, thereby maximizing the measurement accuracy. In addition, the method provided by the present invention increases the measurement range of oxygen content to 1-5wt%, and the measurement range of nitrogen content to 0.5-5wt%, thereby improving the accuracy and stability of the measurement results, and overcoming the problem of large deviations in the measurement results obtained by conventional calibration methods.

[0132] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for simultaneously determining the oxygen and nitrogen contents in titanium materials, characterized in that: The method comprises the following steps: (1) Using a multi-point calibration method, an oxygen standard curve and a nitrogen standard curve are independently established; The method for establishing the nitrogen standard curve is as follows: selecting at least three second standard samples with different nitrogen contents, analyzing the nitrogen content of each second standard sample at least three times, taking the average value and establishing the nitrogen standard curve using a multi-point calibration procedure; the second standard sample is a steel-based standard sample; (2) using a nickel material to wrap the titanium material to be tested to form an inclusion; the mass ratio of the nickel material to the titanium material to be tested is (7-17):1; the mass of the titanium material to be tested is ≤87 mg; (3) placing the inclusion obtained in step (2) in a graphite container, introducing an inert gas and heating the melted inclusion to release carbon monoxide, carbon dioxide and nitrogen; (4) detecting the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium material according to the oxygen standard curve obtained in step (1); (5) detecting the nitrogen obtained in step (3), and determining the nitrogen content in the titanium material according to the nitrogen standard curve obtained in step (1); wherein step (4) and step (5) are performed simultaneously; The oxygen content in the method is measured in the range of 1-5wt%, and the nitrogen content is measured in the range of 0.5-5wt%; The titanium material to be tested in step (2) includes titanium element or titanium alloy; The temperature of the heating and melting in step (3) is 2200-2300°C.

2. The method according to claim 1, characterized in that The method for establishing the oxygen standard curve in step (1) is as follows: selecting at least three first standard samples with different oxygen contents, analyzing the oxygen content of each first standard sample at least three times, taking the average value and establishing the oxygen standard curve using a multi-point calibration procedure.

3. The method according to claim 1, characterized in that Correlation coefficient R of the oxygen standard curve in step (1) 2 ≥0.

99.

4. The method according to claim 2, characterized in that: The first standard sample is a titanium-based standard sample.

5. The method according to claim 1, characterized in that The oxygen standard curve was also subjected to a first accuracy check after being established.

6. The method according to claim 5, characterized in that The specific process of the first accuracy test is: determine the first standard sample of the intermediate oxygen content according to the oxygen standard curve. When the analysis result is within the uncertainty range, it means that the accuracy of the oxygen standard curve is good, otherwise, correction processing is performed.

7. The method according to claim 1, characterized in that Correlation coefficient R of the nitrogen standard curve in step (1) 2 ≥0.

99.

8. The method according to claim 1, characterized in that The nitrogen standard curve was also subjected to a second accuracy check after its establishment.

9. The method according to claim 8, characterized in that The specific process of the second accuracy test is: determine the second standard sample of the intermediate nitrogen content according to the nitrogen standard curve. When the analysis result is within the uncertainty range, it means that the accuracy of the nitrogen standard curve is good, otherwise, correction processing is performed.

10. The method according to claim 1, characterized in that The nickel material in step (2) includes any one of a nickel basket, a nickel capsule, a nickel foil or a nickel foil cup.

11. The method according to claim 1, characterized in that: The graphite container in step (3) includes a graphite crucible.

12. The method according to claim 1, characterized in that The inert gas in step (3) includes helium or argon.

13. The method according to claim 1, characterized in that In step (3), the heating and melting is performed until the oxygen and nitrogen elements in the titanium material are completely released.

14. The method according to claim 1, characterized in that The detection in step (4) is performed using an infrared detector.

15. The method according to claim 1, characterized in that The detection in step (5) is performed using a thermal conductivity detector.

16. The method according to claim 1, characterized in that The method comprises the following steps: (1) The oxygen standard curve and the nitrogen standard curve are independently established using the multi-point calibration method. The specific process is as follows: (a) Select at least three first standard samples with different oxygen contents, analyze the oxygen content of each first standard sample at least three times, take the average value and use the multi-point calibration procedure to establish the correlation coefficient R 2 ≥0.99 oxygen standard curve; a first standard sample of intermediate oxygen content is measured according to the oxygen standard curve, when the analysis result is within the uncertainty range, it means that the accuracy of the oxygen standard curve is good, otherwise it is corrected; the first standard sample is a titanium-based standard sample; (b) Select at least three second standard samples with different nitrogen contents, analyze the nitrogen content of each second standard sample at least three times, take the average value and use the multi-point calibration procedure to establish the correlation coefficient R 2 ≥0.99 nitrogen standard curve; a second standard sample of intermediate nitrogen content is determined according to the nitrogen standard curve. When the analysis result is within the uncertainty range, it indicates that the accuracy of the nitrogen standard curve is good, otherwise a correction is performed; the second standard sample is a steel-based standard sample; (2) using a nickel material to wrap the titanium material to be tested in a mass ratio of (7-17):1 to form an inclusion; the nickel material comprises any one of a nickel basket, a nickel capsule, a nickel foil or a nickel foil cup; the titanium material to be tested comprises a single titanium substance or a titanium alloy, and the mass of the titanium material to be tested is ≤87 mg; (3) placing the inclusion obtained in step (2) in a graphite crucible, introducing helium or argon gas and heating the inclusion at 2200-2300° C. to melt the inclusion until the oxygen and nitrogen elements in the titanium material are completely released in the form of carbon monoxide, carbon dioxide and nitrogen respectively; (4) using an infrared detector to detect the carbon monoxide and carbon dioxide obtained in step (3), and determining the oxygen content in the titanium material according to the oxygen standard curve obtained in step (1); (5) using a thermal conductivity detector to detect the nitrogen obtained in step (3), and determining the nitrogen content in the titanium material according to the nitrogen standard curve obtained in step (1); wherein step (4) and step (5) are performed simultaneously; In the method, the oxygen content is measured in the range of 1-5 wt %, and the nitrogen content is measured in the range of 0.5-5 wt %.

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