Method for detecting elements in nickel-chromium-chromium carbide composite powder

Abstract

The application discloses a method for detecting elements in nickel-chromium-carbide chromium composite powder, and relates to the technical field of component analysis. The method comprises the following steps: grinding and drying the nickel-chromium-carbide chromium composite powder to obtain a powder sample; mixing the powder sample with alumina powder, pre-oxidizing to obtain a pre-oxidized mixture; transferring the pre-oxidized mixture into a platinum-gold crucible containing a composite flux, adding barium nitrate releasing agent drop by drop, adopting segmented gradient heating to perform melting, and obtaining a to-be-detected glass melt piece after cooling; selecting a standard sample to prepare a standard glass melt piece according to the above steps, adding neodymium oxide as an internal standard, adopting an X-ray fluorescence spectrometer to perform measurement, establishing a standard working curve of nickel and chromium elements, and determining the to-be-detected glass melt piece, and combining the standard working curve to calculate the content of nickel and chromium elements. The application does not need strong acid digestion, has no toxic waste liquid, is green and environment-friendly, and greatly improves the detection efficiency compared with traditional methods.

Description

Technical Field

[0001] This invention relates to the field of component analysis technology, specifically to a method for detecting elements in nickel-chromium-chromium carbide composite powder. Background Technology

[0002] Nickel-chromium-chromium carbide (NiCr-Cr3C2) composite powder is a high-performance thermal spray surface strengthening material composed of a nickel-chromium alloy matrix and a chromium carbide hard phase. Due to its excellent wear resistance, corrosion resistance, and high-temperature oxidation resistance, this material is widely used in the preparation of surface coatings for key components such as aerospace engine parts, mining machinery, petrochemical equipment, and electric turbine blades. In materials science, the ratio of the main elements nickel (Ni) to chromium (Cr) directly determines the microstructural stability of the powder itself, thus significantly affecting the mechanical properties (such as bonding strength and hardness) and service life of the subsequent coating. Therefore, rapid and accurate compositional analysis of nickel-chromium-chromium carbide composite powder is a core aspect of quality control.

[0003] Currently, the chemical composition testing of this type of material mainly relies on the industry standard "YS / T 822-2012 Nickel-Chromium-Chromium Carbide Composite Powder". Conventional testing methods mainly include wet chemical digestion-inductively coupled plasma optical emission spectrometry (ICP-OES), titration, direct compression-X-ray fluorescence spectrometry (XRF), and conventional borate fusion-XRF method. However, existing testing technologies have many drawbacks: First, the chromium carbide phase has extremely high chemical stability, and conventional acid dissolution digestion requires high temperature and pressure or strong acid reflux, making the pretreatment process cumbersome and the testing time-consuming. In addition, the testing process consumes a large amount of highly toxic and corrosive reagents, and the resulting heavy metal waste liquid is difficult and costly to treat, posing a serious risk of environmental pollution, and placing extremely high demands on the professional skills and protective levels of operators. Second, if the existing X-ray fluorescence spectrometry adopts the direct compression process, due to the high hardness and density of the chromium carbide phase in the nickel-chromium-chromium carbide composite powder, it is very easy to produce significant particle size effect and mineral effect. Meanwhile, high matrix element content can severely enhance the absorption of characteristic X-rays of the target element, leading to poor detection precision (RSD) and results that often deviate from the true value. Thirdly, to address matrix interference, the industry commonly uses borate melting for film preparation. However, nickel-chromium-chromium carbide composite powders are characterized by high carbon content and strong reducing properties. In conventional melting processes, chromium carbide readily reacts with flux at high temperatures, producing violent splashing and releasing active carbon atoms. These active carbon atoms directly react with platinum-gold (Pt-Au) crucibles to form brittle platinum-carbon alloys, causing the expensive crucibles to become brittle, crack, or even become unusable within a very short time. Summary of the Invention In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for detecting elements in nickel-chromium-chromium carbide composite powder, aiming to solve at least one of the problems in the background art mentioned above.

[0004] This invention provides a method for detecting elements in nickel-chromium-chromium carbide composite powder, the method comprising: The nickel-chromium-chromium-carbide composite powder was ground and dried to obtain a powder sample; The powder sample is mixed with alumina powder and pre-oxidized at a preset temperature to coat the powder sample with alumina and cause the chromium carbide phase to undergo preliminary oxidation and decomposition, resulting in a pre-oxidized mixture. The pre-oxidized mixture was transferred to a platinum-gold crucible containing a composite flux, barium nitrate release agent was added dropwise, and the mixture was melted using a segmented gradient heating method. After cooling, the glass sheet to be tested was obtained. Standard samples were selected and the above steps were performed simultaneously to prepare standard glass flakes. Neodymium oxide was added as an internal standard, and X-ray fluorescence spectrometry was used to determine the standard working curves of nickel and chromium. X-ray fluorescence spectroscopy was performed on the glass slab to be tested, and the content of nickel and chromium in the nickel-chromium-chromium carbide composite powder was calculated by combining the standard working curve.

[0005] Furthermore, the mass ratio of the powder sample to alumina is 1:(1-4).

[0006] Furthermore, the preset temperature is 300℃-500℃, and the pre-oxidation time is 20min-35min.

[0007] Furthermore, the composite flux comprises lithium tetraborate, lithium metaborate and lithium fluoride in a mass ratio of (50-70):(30-50):(5-10).

[0008] Furthermore, the mass ratio of the composite flux to the pre-oxidized mixture is (8-12):1.

[0009] Furthermore, the amount of barium nitrate release agent added is 6-10 drops.

[0010] Furthermore, the segmented gradient heating step includes: Pre-melt at 640℃-660℃ for 8-12 minutes; Pre-melt at 840℃-860℃ for 8-12 minutes; Melt at 1030℃-1100℃ for 9-11 minutes.

[0011] Furthermore, the mass of neodymium oxide added is 4.5%-5.5% of the mass of the standard glass melt.

[0012] Furthermore, the grinding is performed using a planetary ball mill until the material passes through a 0.07mm-0.08mm standard sieve.

[0013] Furthermore, the drying temperature is 80℃-120℃, and the drying time is 1h-3h.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention enables rapid, batch determination of nickel and chromium, the main elements, in nickel-chromium-chromium carbide composite powders. Compared with traditional wet chemical analysis, it eliminates the need for complex acid dissolution and digestion pretreatment, significantly shortening the detection cycle and greatly improving detection efficiency. Simultaneously, X-ray fluorescence spectrometry can determine multiple elements at once, meeting the needs of rapid quality control for large batches of samples in industrial production.

[0015] 2. This invention employs an alumina powder coating and low-temperature pre-oxidation process to completely convert refractory and corrosive substances such as chromium carbide into stable oxides, thus completely avoiding direct contact and reaction between the sample and the platinum-gold crucible during high-temperature melting. This not only effectively prevents corrosion and wear of the precious metal crucible, significantly extending its service life, but also ensures smooth melting and sample preparation, significantly reducing consumable costs.

[0016] 3. By introducing an internal standard element (neodymium) and employing segmented melting technology, combined with the empirical coefficient method for matrix effect correction, the absorption-enhancement effects of sample particle size, molten sheet thickness, and coexisting elements were effectively eliminated. The resulting glass molten sheet was uniform, transparent, and easy to demold, ensuring good repeatability and accuracy of the measurement results. Attached Figure Description

[0017] Figure 1 This is the XRD detection pattern of Comparative Example 1 of the present invention. Detailed Implementation

[0018] To make the objectives, features, and advantages of this invention more apparent and understandable, the invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this invention will be thorough and complete.

[0019] This invention provides a method for detecting elements in nickel-chromium-chromium carbide composite powder, the method comprising: steps S1-S5, Step S1: Grind and dry the nickel-chromium-chromium-carbide composite powder to obtain a powder sample; Among these steps, grinding and refining eliminate the particle size effect, ensuring sufficient subsequent melting reaction; drying removes adsorbed water and crystal water, preventing bubbles or splashing during melting, thus ensuring the uniformity of powder samples and improving detection repeatability.

[0020] Specifically, the grinding process involves using a planetary ball mill to grind the material until it passes through a 0.07mm-0.08mm standard sieve, and the drying temperature is 80℃-120℃ for 1-3 hours.

[0021] Step S2: Mix the powder sample with alumina powder and pre-oxidize it at a preset temperature so that the alumina powder coats the powder sample and the chromium carbide phase undergoes preliminary oxidation and decomposition to obtain a pre-oxidized mixture. The mass ratio of powder sample to alumina powder is 1:(1-4). Alumina powder is chemically stable at high temperatures and coats the surface of sample particles, forming a physical isolation layer that blocks direct contact between the sample and the platinum crucible.

[0022] Furthermore, the preset temperature is 300℃-500℃, and the pre-oxidation time is 20min-35min. The chromium carbide phase on the surface of the powder sample undergoes preliminary oxidation and decomposition (generating Cr2O3 and CO2, etc.), avoiding violent redox reactions that could lead to splashing during subsequent high-temperature melting.

[0023] Step S3: Transfer the pre-oxidized mixture to a platinum-gold crucible containing composite flux, add barium nitrate release agent dropwise, melt using segmented gradient heating, and obtain the glass sheet to be tested after cooling; The composite flux includes lithium tetraborate, lithium metaborate and lithium fluoride, with a mass ratio of (50-70):(30-50):(5-10). Lithium tetraborate and lithium metaborate provide the molten matrix, while lithium fluoride acts as a flux to lower the melting point and improve the melt flowability. The mass ratio of the composite flux to the pre-oxidized mixture is (8-12):1.

[0024] Furthermore, the amount of barium nitrate release agent added is 6-10 drops, which facilitates the demolding of the molten sheet.

[0025] Furthermore, the segmented gradient heating step includes: Pre-melt at 640℃-660℃ for 8-12 minutes; Pre-melt at 840℃-860℃ for 8-12 minutes; Melt at 1030℃-1100℃ for 9-11 minutes.

[0026] The process involves three stages: the first stage, low-temperature exhaust at 640℃-660℃, to remove residual gases; the second stage, medium-temperature homogenization at 840℃-860℃, to allow the pre-oxidized mixture to initially fuse with the composite flux; and the third stage, high-temperature melting at 1030℃-1100℃, to ensure complete liquefaction, avoid splashing caused by thermal shock, produce high-quality glass flakes for testing, eliminate particle size and mineral effects, and provide an ideal homogeneous sample for determination.

[0027] Step S4: Select standard samples and simultaneously perform the above steps to prepare standard glass flakes, add neodymium oxide as an internal standard, and use X-ray fluorescence spectrometry to determine the standard working curves of nickel and chromium elements; The mass of neodymium oxide added was 4.5%-5.5% of the mass of the standard glass slab. The characteristic fluorescence intensity of nickel and chromium in each standard glass slab was measured using X-ray fluorescence spectrometry. Neodymium was used as an internal standard for matrix effect and instrument drift correction. The empirical coefficient method was used for fitting correction, and standard working curves for nickel and chromium were plotted.

[0028] It should be noted that the addition of neodymium oxide can correct errors caused by the thickness of the molten sheet, surface finish, and instrument fluctuations.

[0029] Step S5: Perform X-ray fluorescence spectroscopy on the glass slab to be tested, and calculate the content of nickel and chromium in the nickel-chromium-chromium carbide composite powder based on the standard working curve.

[0030] The present invention is further illustrated below with specific embodiments: Example 1 Embodiment 1 of the present invention provides a method for detecting elements in nickel-chromium chromium carbide composite powder, the method comprising: steps S1-S5, Step S1, Sample preparation: Take nickel-chromium-chromium carbide composite powder, ball mill it in a planetary ball mill until it passes through a 0.074mm (200 mesh) standard sieve, and dry it in a drying oven at 105℃ for 2 hours to obtain a powder sample.

[0031] Step S2, Pre-oxidation: Weigh 0.2000g of powder sample and 0.6000g of alumina powder (≥99.99%) and place them in a ceramic crucible, then mix thoroughly. Place the ceramic crucible in a muffle furnace and pre-oxidize at 460℃ for 28min to obtain a pre-oxidized mixture.

[0032] Step S3, Melting: Transfer the entire pre-oxidized mixture to a platinum-gold crucible pre-filled with 8,000 g of composite flux. Add 8 drops of barium nitrate release agent, then place the crucible in a high-frequency melting machine and perform segmented gradient heating for melting: pre-melting at 660℃ for 10 min, pre-melting at 860℃ for 10 min, and melting at 1060℃ for 10 min. Remove and cool to obtain a flat, transparent glass sheet for testing. The composite flux consists of lithium tetraborate, lithium metaborate, and lithium fluoride in a mass ratio of 60:30:10.

[0033] Step S4, Standard Curve: Select a series of standard samples, prepare them using the same methods as in steps S1-S3, and add 5% neodymium oxide as an internal standard. Measure the samples using X-ray fluorescence spectrometry to establish standard working curves for nickel and chromium. The selected standard samples completely match the test samples in terms of phase, composition, and particle size, with content gradients covering chromium mass fractions of 55.00%–70.00% and nickel mass fractions of 20.00%–30.00%.

[0034] Step S5, determination: X-ray fluorescence spectroscopy is performed on the glass slab to be tested, and the content of nickel and chromium in the nickel-chromium chromium carbide composite powder is calculated in combination with the standard working curve.

[0035] Method detection limit and lower limit of quantitation: Following the standard X-ray fluorescence spectrometry analysis procedure, blank fused sections were measured 11 times consecutively. The limit of detection (LOD) was calculated using 3 times the standard deviation, and the lower limit of quantitation (LOQ) was calculated using 10 times the standard deviation. In this method, the LOD for chromium was 0.012%, and the LOD for quantitation was 0.040%; the LOD for nickel was 0.010%, and the LOD for quantitation was 0.033%.

[0036] For this invention, samples 1 and 2 were used. Nine glass flakes were independently prepared from the same sample according to the steps outlined in this invention. The Cr and Ni content were measured and recorded nine times (n=9). The relative standard deviation (RSD) was calculated using the following formula: RSD = standard deviation / arithmetic mean × 100%.

[0037] The Cr content of sample 1 was measured nine times and the values ​​were 64.78%, 64.89%, 64.71%, 64.65%, 64.74%, 64.90%, 64.83%, 64.81%, and 64.68%, respectively.

[0038] The nine Ni content measurements for sample 1 were 23.36%, 23.24%, 23.38%, 23.31%, 23.25%, 23.38%, 23.26%, 23.23%, and 23.37%, respectively.

[0039] The Cr content of sample 2 was measured nine times and the values ​​were 62.12%, 62.19%, 62.29%, 62.18%, 62.23%, 62.30%, 62.26%, 62.15%, and 62.16%, respectively.

[0040] The nine Ni content measurements for sample 2 were 25.82%, 25.89%, 25.97%, 25.92%, 25.95%, 25.83%, 25.79%, 25.80%, and 25.79%, respectively.

[0041] To further verify the long-term durability of the crucible, this invention conducted 500 consecutive melting and sample preparation tracking tests. The platinum-gold crucible was weighed at constant weight before and after each test: initial mass of the crucible m 1= 79.2680g, mass m after 500 consecutive uses 2= 79.1491g, calculate the weight loss rate = (m1-m2) / m1×100%.

[0042] Calculations show that the crucible weight loss rate is only 0.15%, and the inner wall is free of pitting, dark spots, and obvious corrosion pits, with a surface roughness Ra < 0.85 μm. The service life is increased tenfold, significantly reducing the replacement cost of precious metal consumables due to crucible wear, while also reducing sample preparation deviations caused by frequent crucible replacements, thus significantly improving the long-term stability of the analytical method.

[0043] Example 2 The difference between Example 2 and Example 1 is that in step S2, the pre-oxidation conditions are adjusted to 420°C for 28 minutes, while the remaining steps are the same as in Example 1.

[0044] The Cr content of sample 1 was measured nine times and the values ​​were 64.39%, 64.27%, 64.92%, 64.59%, 64.47%, 64.81%, 64.78%, 64.20%, and 64.19%, respectively.

[0045] The nine Ni element content measurements for sample 1 were 23.04%, 23.47%, 23.28%, 23.20%, 23.05%, 23.51%, 23.01%, 23.43%, and 23.11%, respectively.

[0046] The Cr content of sample 2 was measured nine times and was 62.24%, 61.89%, 61.92%, 62.39%, 61.90%, 62.43%, 61.74%, 62.01%, and 62.12%, respectively.

[0047] The nine Ni content measurements for sample 2 were 25.61%, 25.55%, 25.40%, 25.88%, 25.47%, 25.39%, 25.70%, 25.64%, and 25.82%, respectively.

[0048] Compared to Example 1, the fused sheet contains a small amount of black carbon inclusions, resulting in poor light transmittance and reduced precision.

[0049] Example 3 The difference between Example 3 and Example 1 is that in step S2, 0.2000g of powder sample and 0.5000g of high-purity alumina powder (mass ratio 1:2.5) are weighed, and the remaining steps are the same as in Example 1.

[0050] The Cr content of sample 1 was measured nine times and the values ​​were 64.35%, 64.61%, 64.79%, 64.32%, 64.72%, 64.49%, 64.87%, 64.55%, and 64.38%, respectively.

[0051] The nine Ni element content measurements for sample 1 were 23.04%, 23.31%, 23.20%, 23.38%, 23.53%, 23.29%, 23.01%, 23.47%, and 23.48%, respectively.

[0052] The Cr content of sample 2 was measured nine times and the values ​​were 62.04%, 61.91%, 62.39%, 62.21%, 62.32%, 61.89%, 62.47%, 62.45%, and 62.08%, respectively.

[0053] The nine Ni element content measurements for sample 2 were 25.64%, 25.41%, 25.71%, 25.38%, 25.63%, 25.89%, 25.31%, 25.57%, and 25.90%, respectively.

[0054] Compared to Example 1, the alumina coating is thinner and cannot completely isolate the sample from the crucible, posing a risk of corrosion, and the fused sheet has uneven light transmission.

[0055] Example 4 The difference between Example 4 and Example 1 is that in step S3, the composite flux ratio is adjusted to lithium tetraborate: lithium metaborate: lithium fluoride = 65:30:5, and the remaining steps are the same as in Example 1.

[0056] The Cr content of sample 1 was measured nine times and the values ​​were 64.57%, 63.92%, 65.18%, 64.76%, 65.09%, 64.35%, 64.67%, 64.28%, and 64.51%, respectively.

[0057] The nine Ni element content measurements for sample 1 were 23.27%, 23.01%, 23.49%, 23.66%, 23.35%, 23.15%, 23.61%, 23.29%, and 23.21%, respectively.

[0058] The Cr content of sample 2 was measured nine times and the values ​​were 62.08%, 61.93%, 62.39%, 62.27%, 62.00%, 61.96%, 62.48%, 62.59%, and 62.42%, respectively.

[0059] The nine Ni content measurements for sample 2 were 25.82%, 25.37%, 25.24%, 25.71%, 25.35%, 25.90%, 25.56%, 25.34%, and 25.46%, respectively.

[0060] Compared to Example 1, the overall viscosity of the flux is higher, the melt flow is poor, the thickness of the melt sheet is uneven, with the center being thicker than the edges; the demolding resistance is high, and the crucible edge sticking occurs multiple times, with tiny air bubbles inside the melt sheet.

[0061] Example 5 The difference between Embodiment 5 and Embodiment 1 is that in step S3, the segmented melting temperature is adjusted to 580℃ for 10 min, 780℃ for 10 min, and 1060℃ for 10 min, while the remaining steps are the same as in Embodiment 1.

[0062] The Cr content of sample 1 was measured nine times and the values ​​were 64.21%, 64.84%, 64.05%, 64.97%, 64.12%, 64.78%, 65.03%, 64.33%, and 64.69%, respectively.

[0063] The nine Ni element content measurements for sample 1 were 23.00%, 23.52%, 22.89%, 23.64%, 23.08%, 23.45%, 23.70%, 23.38%, and 23.16%, respectively.

[0064] The Cr content of sample 2 was measured nine times and the values ​​were 61.92%, 62.56%, 61.80%, 62.67%, 62.01%, 62.49%, 62.72%, 62.15%, and 62.41%, respectively.

[0065] The nine Ni element content measurements for sample 2 were 25.03%, 25.86%, 25.41%, 25.65%, 25.30%, 25.74%, 25.21%, 25.42%, and 25.66%, respectively.

[0066] Compared to Example 1, the pre-melting temperature was insufficient, the sample was not completely wetted and degassed by the flux, and the molten sheet had alternating light and dark areas and poor overall uniformity.

[0067] Example 6 The difference between Example 6 and Example 1 is that in step S4, the 5% neodymium oxide internal standard is replaced with an equal mass fraction of lanthanum oxide internal standard. The remaining steps are the same as in Example 1.

[0068] The Cr content of sample 1 was measured nine times and the values ​​were 64.94%, 64.01%, 65.57%, 63.82%, 65.46%, 63.67%, 65.68%, 64.19%, and 64.86%, respectively.

[0069] The nine Ni content measurements for sample 1 were 23.52%, 22.64%, 24.26%, 22.45%, 24.15%, 22.30%, 24.38%, 22.81%, and 23.43%, respectively.

[0070] The Cr content of sample 2 was measured nine times and the values ​​were 62.37%, 61.44%, 63.00%, 61.25%, 62.89%, 61.10%, 63.11%, 61.62%, and 62.29%, respectively.

[0071] The nine Ni content measurements for sample 2 were 26.10%, 25.22%, 26.84%, 25.03%, 26.73%, 24.88%, 26.96%, 25.39%, and 26.01%, respectively.

[0072] Compared to Example 1, the characteristic spectral lines of lanthanum oxide and impurity spectral lines overlap and interfere significantly, resulting in a substantial decrease in the effectiveness of matrix correction and instrument drift compensation.

[0073] Comparative Example 1 The difference between Comparative Example 1 and Example 1 of the present invention is as follows: In step S1, the drying temperature is 90°C; In step S2, weigh 0.4000g of powder sample and 0.4000g of alumina powder, pre-oxidize at 400℃ for 15min, and keep other steps unchanged.

[0074] The Cr content of sample 1 was measured nine times and the values ​​were 63.24%, 62.29%, 64.21%, 63.49%, 62.73%, 63.59%, 62.01%, 61.00%, and 62.68%, respectively.

[0075] The nine Ni element content measurements for sample 1 were 22.10%, 23.45%, 23.57%, 22.42%, 23.91%, 22.51%, 22.00%, 23.11%, and 23.04%, respectively.

[0076] The Cr content of sample 2 was measured nine times and the values ​​were 61.11%, 61.19%, 62.51%, 61.68%, 61.94%, 62.60%, 61.39%, 62.42%, and 60.68%, respectively.

[0077] The nine Ni content measurements for sample 2 were 26.01%, 24.69%, 24.06%, 24.48%, 25.54%, 24.62%, 25.05%, 25.18%, and 25.00%, respectively.

[0078] The fused sheet prepared from sample 1 was ground into fine powder and subjected to XRD scanning, such as... Figure 1 As shown, the presence of chromium carbide and chromium characteristic diffraction peaks in multiple locations in the detection spectrum indicates that the sample oxidation was incomplete, the matrix composition was not uniform, and the accuracy of the measurement decreased.

[0079] Comparative Example 2 The difference between Comparative Example 2 and Example 1 of the present invention is as follows: Without adding alumina, directly weigh 0.2000g of powder sample, oxidize it at high temperature for 2h, and then mix and melt it with 8.000g of composite flux. Other steps remain unchanged.

[0080] The Cr content of sample 1 was measured nine times and the values ​​were 62.34%, 61.09%, 64.63%, 63.72%, / , 62.60%, / , 62.46%, and 63.28%, respectively.

[0081] The nine Ni element content measurements for sample 1 were 22.32%, 21.90%, 21.05%, 21.97%, 22.69%, 21.28%, and 21.47%, respectively.

[0082] The nine Cr element content measurements for sample 2 were 61.29%, 60.46%, / , / , 61.90%, 62.31%, 60.21%, 63.26%, / .

[0083] The nine Ni content measurements for sample 2 were 24.35%, 25.12%, / , / , 23.87%, 24.21%, 23.78%, 23.49%, and / , respectively. The " / " indicates that the sample was cracked or damaged and could not be measured normally, lacked alumina insulation protection, or had severely corroded crucibles with gray corrosion spots. The inner wall roughness of the crucible was measured using a stylus-type surface roughness meter. Before the test, the initial roughness of the inner wall of the crucible was Ra = 0.70 μm; after the sample directly contacted the crucible and melted at high temperature, the inner wall developed dissolution pits, and the roughness increased to Ra = 4.59 μm.

[0084] Comparative Example 3 The difference between Comparative Example 3 and Example 1 of the present invention is as follows: The conventional powder compression method was used: Nickel-chromium-chromium carbide composite powder was ball-milled using a planetary ball mill until it passed through a 0.074 mm (200 mesh) standard sieve, dried in a 105℃ drying oven for 2 hours, and then cooled to room temperature. 4.000 g of the test powder was weighed and mixed thoroughly with 1 g of boric acid. The entire sample was poured into a mold, using boric acid as the substrate. A pressure of 20t was applied on a tablet press and held for 30 seconds to compress the sample into a tablet form. The sample was then directly tested without the addition of an internal standard.

[0085] The nine Cr values ​​for sample 1 were 62.03%, 65.91%, 63.25%, 60.77%, 63.04%, 61.28%, 63.47%, 64.72%, and 62.29%, respectively.

[0086] The nine Ni measurements for sample 1 were 23.15%, 20.08%, 22.37%, 19.94%, 22.16%, 20.44%, 22.61%, 20.87%, and 21.36%, respectively.

[0087] The Cr content of sample 2 was measured nine times and was 60.34%, 62.42%, 62.90%, 59.39%, 61.35%, 61.72%, 63.55%, 62.21%, and 61.34%, respectively.

[0088] The nine Ni content measurements for sample 2 were 23.56%, 22.35%, 24.44%, 22.67%, 23.17%, 21.75%, 23.00%, 21.93%, and 25.11%, respectively.

[0089] Conventional tableting methods cannot eliminate mineral effects and particle size effects, resulting in severe matrix interference and failing to meet detection requirements in terms of accuracy and repeatability.

[0090] Comparative Example 4 The difference between Comparative Example 4 and Example 1 of this invention is as follows: Cr was titrated with ferrous ammonium sulfate standard solution, and Ni was titrated with EDTA standard solution.

[0091] The measured Cr content of sample 1 was 64.82%.

[0092] The measured value of Ni element content in sample 1 was 23.26%.

[0093] The measured Cr content of sample 2 was 62.13%.

[0094] The measured value of Ni element content in sample 2 was 25.91%.

[0095] It is evident that the method described herein deviates very little from the chemical method, and the method has high reliability.

[0096] Please refer to Table 1 below, which shows the parameters corresponding to the above embodiments and comparative examples of the present invention. The parameters are based on the measured values ​​of Cr and Ni elements (n=9) from nine measurements of Sample 1 and Sample 2. The relative standard deviation (RSD) is calculated using the following formula: RSD = Standard deviation / Arithmetic mean × 100%.

[0097] Table 1

[0098] As shown in Table 1, the method of this invention is significantly superior to the three comparative examples in terms of precision, accuracy, fused sheet quality, and crucible protection. By optimizing the pre-oxidation process and melting conditions, the glass fused sheet produced by this invention is uniform, transparent, and easy to demold, exhibiting almost no corrosion to the platinum-gold crucible and greatly reducing equipment wear. The test results show good repeatability and minimal deviation from the chemical method, demonstrating high reliability. In contrast, Comparative Example 1 suffers from a significant decrease in precision due to incomplete oxidation; Comparative Example 2 completely omits the pre-oxidation treatment, resulting in fused sheet breakage, difficulty in demolding, severe crucible corrosion, and extremely high data dispersion, rendering the method ineffective; Comparative Example 3 uses a powder pressing method, exhibiting a significant particle size effect, failing to eliminate the mineral effect, and resulting in poor test stability due to easy powder shedding. Comparative Example 4, using chemical titration, shows minimal deviation and is accurate and reliable.

[0099] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for detecting elements in nickel-chromium-chromium carbide composite powder, characterized in that, The method includes: The nickel-chromium-chromium-carbide composite powder was ground and dried to obtain a powder sample; The powder sample and alumina powder are placed in a ceramic crucible and mixed evenly. The ceramic crucible is then placed in a muffle furnace and pre-oxidized at a preset temperature to allow the alumina to coat the powder sample and to cause the chromium carbide phase to undergo preliminary oxidation and decomposition, thereby obtaining a pre-oxidized mixture. The preset temperature is 300℃-500℃ and the pre-oxidation time is 20min-35min. The pre-oxidized mixture was transferred to a platinum-gold crucible containing a composite flux, and barium nitrate release agent was added dropwise. Melting was carried out using a segmented gradient heating method. After cooling, the glass sheet to be tested was obtained. The segmented gradient heating step included: pre-melting at 640℃-660℃ for 8 min-12 min, pre-melting at 840℃-860℃ for 8 min-12 min, and melting at 1030℃-1100℃ for 9 min-11 min. Standard samples were selected and the above steps were performed simultaneously to prepare standard glass flakes. Neodymium oxide was added as an internal standard, and X-ray fluorescence spectrometry was used to determine the standard working curves of nickel and chromium. X-ray fluorescence spectroscopy was performed on the glass slab to be tested, and the content of nickel and chromium in the nickel-chromium-chromium carbide composite powder was calculated by combining the standard working curve.

2. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The mass ratio of the powder sample to alumina powder is 1:(1-4).

3. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The composite flux comprises lithium tetraborate, lithium metaborate and lithium fluoride, in a mass ratio of (50-70):(30-50):(5-10).

4. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 3, characterized in that, The mass ratio of the composite flux to the pre-oxidized mixture is (8-12):

1.

5. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The amount of barium nitrate release agent added is 6-10 drops.

6. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The amount of neodymium oxide added is 4.5%-5.5% of the mass of the standard glass melt.

7. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The grinding process involves using a planetary ball mill to grind the material until it passes through a 0.07mm-0.08mm standard sieve.

8. The method for detecting elements in nickel-chromium-chromium carbide composite powder according to claim 1, characterized in that, The drying temperature is 80℃-120℃, and the time is 1h-3h.

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