A powder standard sample and its preparation method and application

Abstract

The present invention proposes a powder standard sample comprising at least one of titanium carbonitride, titanium carbide, and titanium nitride; wherein the nitrogen content is 3% to 22%, the oxygen content is less than 1.0%, the hydrogen content is less than 0.05%, and the total impurity elements are less than 0.2%. When the powder standard sample is used for testing, the data is fitted into a working curve using a linear regression method with a linear coefficient of 0.9998, indicating good linearity. The resulting working curve meets the high nitrogen analysis range of refractory metals such as tungsten, titanium, tantalum, and niobium, as well as ceramic alloy samples, and provides stable, accurate, and reliable test results.

Description

Technical Field

[0001] The invention belongs to the technical field of standard samples, and in particular relates to a powder standard sample and a preparation method and application thereof. Background Art

[0002] Market research has found that the demand for sample analysis in the fields of refractory metals such as powder metallurgy, cemented carbide and ceramic alloys is increasing. The control of nitrogen content in the samples is a key technical parameter of the product. The nitrogen content of metal ceramic alloy samples is greater than 3%, which is a high-nitrogen product. Due to the differences in the methods and standard samples used by various companies to analyze high nitrogen content, the test results also show large deviations, which have led to objections in the product process production ingredient control and user use.

[0003] Standard samples are primarily used for nitrogen analysis using the thermal conductivity method. The analytical results and accuracy are completely dependent on the characteristic values ​​of the standard samples. Using nitrogen-carbon-titanium-based products as high-nitrogen standard samples facilitates the calibration of measuring instruments, evaluation of measurement methods and processes, and ensures the consistency and comparability of measurement results. They also play a crucial role in product quality arbitration, product inspection, and quality control and evaluation by certification bodies.

[0004] Currently, high-nitrogen analysis both domestically and internationally generally uses nitrogen standards made from steel to calibrate instruments. With the widespread use of ceramic materials, the demand for testing samples with high nitrogen content (>3%) is growing. However, high-nitrogen standard samples are currently very scarce on the market. They are all single high-nitrogen standard samples in different matrices. The nitrogen content range cannot meet the requirements of refractory metals such as tungsten, titanium, tantalum, niobium, and ceramic materials, as well as refractory metal samples such as metal-ceramic alloys. The working curve cannot meet the requirement of a linear coefficient of 0.999, and the detection accuracy is seriously deviated. For refractory metals such as tungsten, titanium, tantalum, niobium, and metal-ceramic alloys, the material matrix of the steel standard samples is too different from that of the refractory metals. Key parameters such as the analytical power set for the instrument are completely different, and the calibration and measurement conditions are different, resulting in systematic errors in the measurement results.

[0005] Therefore, there is an urgent need for a nitrogen element analysis standard sample with high melting point, high strength, strong wear resistance, corrosion resistance, oxidation resistance and other excellent properties, as well as good long-term stability and uniformity. Summary of the Invention

[0006] In order to solve the above problems in the prior art, the present invention proposes a powder standard sample and a preparation method and application thereof.

[0007] In a first aspect, the present invention provides a powder standard sample comprising at least one of titanium carbonitride, titanium carbide, and titanium nitride;

[0008] The nitrogen content is 3% to 22%; the oxygen content is less than 1.0%; the hydrogen content is less than 0.05%; and the total amount of impurity elements is less than 0.2%.

[0009] As a specific embodiment of the present invention, the powder standard sample is composed of a nitrogen-carbon-titanium-based substance, whose important components are titanium carbonitride, titanium nitride, and titanium carbide. Its melting characteristics meet the needs of nitrogen content analysis in refractory metal products such as powder metallurgy, cemented carbide and ceramics, and it has good compatibility with nickel foil.

[0010] As a specific embodiment of the present invention, the impurity elements include Fe<0.050%, Mn<0.020%, Si<0.050%, Ca<0.020%, K<0.005%, Na<0.005%, S<0.005% and other elements<0.10%. As a specific embodiment of the present invention, the powder standard sample includes 5 standard point values, for example, the nitrogen content is: standard point 1: 3%~6%; standard point 2: 7%~11%; standard point 3: 12%~15%; standard point 4: 16%~19%; standard point 5: 20%~22%.

[0011] As a specific embodiment of the present invention, the powder standard sample has a Fisher's average particle size of 1 μm to 3 μm. Specifically, its Fisher's average particle size is between 1 μm and 3 μm, and the particle size distribution is: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; D90 is between 6 μm and 10 μm; and D10 / D90 is between 0.05 and 0.2, which can well ensure complete release on the nitrogen analyzer.

[0012] As a specific embodiment of the present invention, the oxygen content of the powder standard sample is not higher than 0.50%, and the hydrogen content is not higher than 0.015%, which can avoid the influence of oxygen and hydrogen on nitrogen analysis and meet the accuracy and precision of nitrogen.

[0013] In a second aspect, the present invention provides a method for preparing the powder standard sample, which comprises mixing at least one of titanium carbonitride, titanium carbide and titanium nitride.

[0014] As a specific embodiment of the present invention, the preparation method of titanium carbide includes: placing a mixture of TiO2 (titanium dioxide) and C (carbon black) in an appropriate proportion in a graphite furnace, and forming titanium carbide at a high temperature of 1800-2000°C, preferably 1900°C, in a vacuum environment.

[0015] The overall reaction formula of the process is:

[0016] TiO2+3C→TiC+2CO↑

[0017] As a specific embodiment of the present invention, the preparation method of titanium carbonitride includes: on the basis of the carburization process, according to the required C / N ratio, appropriate TiO2 (titanium dioxide) and C (carbon black) are formulated, the appropriate N2 flow rate is controlled, and at a high temperature of 1700-1900°C, preferably 1800°C, the carburization, nitridation and solid solution processes are completed to form titanium carbonitride.

[0018] The main reaction formula of the process is:

[0019] TiC+TiO2+C+N→Ti(C,N)

[0020] As a specific embodiment of the present invention, the method for preparing titanium nitride includes: heating titanium powder at a high temperature of 1100 to 1300° C., preferably 1200° C., in a nitrogen atmosphere to form titanium nitride.

[0021] The overall equation for the process is:

[0022] 2Ti+N2→2TiN

[0023] The above raw materials in the present invention can be prepared in-house or purchased commercially, and the present invention is not particularly limited thereto.

[0024] In a third aspect, the present invention provides an application of the powder standard sample in the field of nitrogen content analysis.

[0025] As a specific embodiment of the present invention, the powder standard sample is applied to the fields of powder metallurgy and ceramic alloys.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The powder standard sample of the present invention is a standard sample based on nitrogen, carbon and titanium, which replaces the steel standard sample in the existing technology and has high practicality. At present, there are no such standard samples at home and abroad. The standard sample can be continuously adjusted within the range of 3%-22% in nitrogen value. When testing the sample, the most suitable standard point can be selected according to the nitrogen value.

[0028] 2. The nitrogen-carbon-titanium-based powder standard sample of the present invention has excellent properties such as high melting point, high strength, strong wear resistance, corrosion resistance and oxidation resistance, and good long-term stability and uniformity. The nitrogen-carbon-titanium-based material is used as the standard sample of the high nitrogen series of cemented carbide, and the aging can be traced back for more than ten years, which meets the basic conditions as a standard sample.

[0029] 3. The conventional steel standard weighing weight is typically 0.50-1.00g, while the refractory metal weighing weight is typically 0.03-0.05g, which can result in a 20-fold error. Using nitrogen-carbon-titanium-based standards maintains consistency in weighing weight for the analysis of similar refractory metals, reducing weighing errors. This ensures the accuracy of analytical results and significantly improves precision.

[0030] 4. In the existing steel standard samples, the nitrogen release temperature of steel and refractory metals of cemented carbide is very different, so the analysis power and other parameters set for the instrument are completely different. The nitrogen of the steel standard sample can be completely released at a power of 3500W, while the refractory metal requires at least 4800W. The calibration and measurement conditions are different, resulting in systematic errors in the measurement results.

[0031] 5. Due to their high melting points, refractory metals such as carbide must be wrapped in nickel foil for fluxing. However, steel standards are analyzed directly without fluxing, and their blank values ​​differ from those of the nickel foil blank. Using steel standards to create working curves can result in significant analytical errors for refractory metals. If nickel foil is also used to melt the steel standard, the reaction is too intense, resulting in expansion and bubbling, making the standard analysis unstable and inaccurate.

[0032] 6. The nitrogen-carbon-titanium-based powder standard sample of this invention, because its melting point is consistent with refractory metals and cermet alloys containing tungsten, titanium, tantalum, and niobium, can be wrapped with nickel foil for fluxing. It can be completely melted at a power of 4800W to 5000W, rapidly releasing nitrogen with a good peak shape and no tailing, resulting in excellent analytical accuracy. The nitrogen-carbon-titanium-based material is used as a high-nitrogen standard sample on the oxygen-nitrogen analyzer to generate a working curve. The working curve has excellent linearity and stability, ensuring accurate and reliable high-nitrogen analysis results for refractory metals and ceramic alloys such as tungsten, titanium, tantalum, niobium, and ceramic metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a working curve diagram of a test example of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific examples, but they do not constitute any limitation to the present invention.

[0035] In each embodiment of the present invention, the specific information of the reagents used is as follows:

[0036] High-purity titanium dioxide (TiO2), purity 99.5%, average particle size: <4μm;

[0037] High-purity carbon black (C), purity 99.5%, Fisher particle size: <4μm;

[0038] High-purity titanium powder, purity 99.9%, average particle size: <50μm.

[0039] Example 1

[0040] This embodiment provides a powder standard sample and a preparation method thereof, the specific details of which are as follows:

[0041] S1: TiO2 (titanium dioxide) and C (carbon black) are mixed in a ratio of 8:2, and the mixture is placed in a graphite furnace to form titanium carbide at a high temperature of 1900°C in a vacuum environment.

[0042] S2: Titanium dioxide (TiO2) and carbon black (C) are mixed in a ratio of 8:2 under a nitrogen environment and titanium carbonitride is formed at a high temperature of 1800°C.

[0043] S3: Particle size formation: After crushing and classification, titanium carbonitride powder meeting the particle size distribution requirements is obtained.

[0044] The powder standard sample obtained in Example 1 is composed of titanium carbonitride, wherein the nitrogen content is 10%, the average particle size is 1 μm to 4 μm, and the particle size distribution is as follows: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; and D90 is between 6 μm and 10 μm.

[0045] Example 2

[0046] This embodiment provides a powder standard sample and a preparation method thereof, the specific details of which are as follows:

[0047] S1: Titanium powder is heated to 1200°C in a nitrogen atmosphere to form titanium nitride.

[0048] S2: The titanium carbonitride and titanium nitride prepared in Example 1 are prepared in a mass ratio of 4:6, and mixed through a process to obtain a mixed powder of titanium carbonitride + titanium nitride.

[0049] S3: Particle size formation: After crushing and classification, titanium carbonitride + titanium nitride powder meeting the particle size distribution requirements is obtained.

[0050] The powder standard sample obtained in Example 2 consists of titanium carbonitride and titanium nitride, wherein the nitrogen content is 17%. The average particle size is 1 μm to 4 μm, wherein the particle size distribution is: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; D90 is between 6 μm and 10 μm;

[0051] Example 3

[0052] This embodiment provides a powder standard sample and a preparation method thereof, the specific details of which are as follows:

[0053] S1: TiO2 (titanium dioxide) and C (carbon black) are mixed in a ratio of 8:2, and the mixture is placed in a graphite furnace to form titanium carbide at a high temperature of 1900°C in a vacuum environment.

[0054] S2: In a nitrogen atmosphere, titanium powder is heated to 1200° C. to form titanium nitride.

[0055] S3: The titanium carbonitride, titanium nitride and titanium carbide of Example 1 are prepared in a mass ratio of 4:4:2, and mixed through a process to obtain a mixed powder of titanium carbonitride+titanium nitride+titanium carbide.

[0056] S4: Particle size formation: After crushing and classification, titanium carbonitride + titanium nitride + titanium carbide powder meeting the particle size distribution requirements is obtained.

[0057] The powder standard sample obtained in Example 3 consists of titanium carbonitride, titanium nitride, and titanium carbide, each containing 13% nitrogen. The average particle size is 1 μm to 4 μm, and the particle size distribution is as follows: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; and D90 is between 6 μm and 10 μm.

[0058] Example 4

[0059] This embodiment provides a powder standard sample and a preparation method thereof, the specific details of which are as follows:

[0060] S1: TiO2 (titanium dioxide) and C (carbon black) are mixed in a ratio of 8:2, and the mixture is placed in a graphite furnace to form titanium carbide at a high temperature of 1900°C in a vacuum environment.

[0061] S2: The titanium carbonitride and titanium carbide of Example 1 are prepared in a mass ratio of 5:5, and mixed through a process to obtain a mixed powder of titanium carbonitride + titanium carbide.

[0062] S3: Particle size formation: After crushing and classification, titanium carbonitride + titanium carbide powder meeting the particle size distribution requirements is obtained.

[0063] The powder standard sample obtained in Example 4 comprises titanium carbonitride and titanium carbide, wherein the nitrogen content is 5%.

[0064] The average particle size is 1 μm to 4 μm, wherein the particle size distribution is: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; and D90 is between 6 μm and 10 μm.

[0065] Example 5

[0066] This embodiment provides a powder standard sample and a preparation method thereof, the specific details of which are as follows:

[0067] S1: Titanium powder is heated to 1200°C in a nitrogen atmosphere to form titanium nitride.

[0068] S2: Particle size formation: After crushing and classification, titanium nitride powder that meets the particle size distribution requirements is obtained.

[0069] The powder standard sample obtained in Example 5 is composed of titanium nitride, wherein the nitrogen content is 21%, the average particle size is 1 μm to 4 μm, and the particle size distribution is as follows: D10 is between 0.50 μm and 1.0 μm; D50 is between 1.0 μm and 4.0 μm; and D90 is between 6 μm and 10 μm.

[0070] Test Case

[0071] A nitrogen-carbon-titanium based high nitrogen standard sample was used on the oxygen-nitrogen analyzer to prepare a working curve.

[0072] The powder standard sample obtained in Example 4 was selected and tested using the distillation method and thermal conductivity method of the national standard absolute method. The nitrogen content was 4.85%, and the powder standard sample obtained in Example 1, wherein the nitrogen content was 10.26%. Two standard points of nitrogen-carbon-titanium-based powder high nitrogen standard samples were weighed 0.04g each, wrapped with nickel foil for fluxing, set the power to 5000W, and analyzed for 70s. The nitrogen content was detected by thermal conductivity. The detection peak showed a normal distribution, complete release, and good analytical accuracy. The detection data of the standard points were fitted into a working curve using a linear regression method. The linear coefficient was 0.9998, indicating good linearity. The working curve can meet the high nitrogen analysis range of refractory metals and ceramic alloy samples such as tungsten, titanium, tantalum, and niobium, and its detection results are stable, accurate and reliable.

[0073] The working curve prepared by nitrogen-carbon-titanium-based high nitrogen standard sample was used to detect the metal ceramic sample, and the standard deviation and relative standard deviation were calculated.

[0074] Table 1 Results of testing metal ceramic samples using working curves made with nitrogen-carbon-titanium-based high nitrogen standard samples

[0075]

[0076] In summary, the nitrogen-carbon-titanium-based powder standard sample of the present invention, because its melting point is consistent with refractory metals and cermet alloys containing tungsten, titanium, tantalum, and niobium, can be wrapped with nickel foil for fluxing. It can be completely melted at a power of 4800W to 5000W, rapidly releasing nitrogen with a good peak shape and no tailing, achieving excellent analytical accuracy. The nitrogen-carbon-titanium-based material was used as a high-nitrogen standard sample on the oxygen-nitrogen analyzer to generate a working curve. The working curve has excellent linearity and stability, ensuring the accuracy and reliability of high-nitrogen analysis results for refractory metals and ceramic alloys such as tungsten, titanium, tantalum, niobium, and ceramic metals.

[0077] Any numerical value mentioned in the present invention includes all values ​​that increase by one unit each time from the lowest value to the highest value if there is only a gap of two units between any minimum value and any maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is stated to be 50-90, it is meant in this specification to specifically list values ​​such as 51-89, 52-88... and 69-71 and 70-71. For non-integer values, it is appropriate to consider units of 0.1, 0.01, 0.001 or 0.0001. These are just some special examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed lowest value and the listed highest value are considered to have been disclosed.

[0078] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. Application of a powder standard sample in detecting high nitrogen content in metal ceramics, characterized in that: The powder standard sample is titanium carbonitride; wherein the nitrogen content is 3% to 22% by weight; the oxygen content is less than 1.0% by weight; the hydrogen content is less than 0.05% by weight; the total amount of impurity elements is less than 0.2% by weight; and the particle size of the powder standard sample is 1 μm to 3 μm. Use powder standard samples to make a working curve on the oxygen and nitrogen analyzer. Set the power of the oxygen and nitrogen analyzer to 4800W~5000W. The preparation method of titanium carbonitride comprises: mixing TiO2 and C in a nitrogen environment, and treating the mixture at 1700-1900°C to form titanium carbonitride.

2. The use according to claim 1, characterized in that Among the impurity elements, Fe<0.050%, Mn<0.020%, Si<0.050%, Ca<0.020%, K<0.005%, Na<0.005%, S<0.005% and other elements<0.10%.

3. The use according to claim 1 or 2, characterized in that The powder standard sample includes 5 standard point values, and the nitrogen content is as follows: standard point 1: 3% to 6%; standard point 2: 7% to 11%; standard point 3: 12% to 15%; standard point 4: 16% to 19%; and standard point 5: 20% to 22%.

4. The use according to claim 1 or 2, characterized in that The oxygen content of the powder standard sample is not higher than 0.50%, and the hydrogen content is not higher than 0.015%.

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