The primary γ′ phase is the main strengthening phase that determines the properties of superalloys, so it is of great significance to analyze the size and volume fraction of the primary γ′ phase. This study focused on the microstructure characteristics of the primary γ′ phase in GH4096 superalloy. The three-dimensional morphology of the primary γ′ phase was accurately characterized by focused ion beam (FIB) three-dimensional reconstruction technology. The two-dimensional large-field characterization was conducted using high-throughput scanning electron microscopy. It was found that the primary γ′ phase in the three-dimensional slice had several interference factors such as irregular shape, similar gray level to the background, and containing twin crystals inside some crystalline grains, which was not easy to identify. Therefore, the artificial intelligence technology was introduced to rapidly identify the primary γ′ phase in images of three-dimensional slice, and the three-dimensional visual characterization was finally realized. The three-dimensional characterization and two-dimensional characterization were compared, and the results showed that the size of the primary γ′ phase was concentrated above 1.5 μm in two methods. The cumulative volume fraction and area fraction were basically consistent, i.e., 14.915% and 14.925%, respectively. Compared to the conventional two-dimensional image analysis, the three-dimensional characterization could provide more information to comprehensively describe the microstructure of the primary γ′ phase, and the spatial arrangement of primary γ′ phase could be displayed more clearly.

The sulfide in non-quenched and tempered steel is an important index to evaluate the product quality. The control of its morphology and distribution is the key bottleneck to the improvement of steel quality and performance. The morphology, grading and segregation of sulfide in 36MnVS4 non-quenched and tempered steel before and after tellurium modification were analyzed and compared by metallographic microscope, scanning electron microscope (SEM) and carbon-sulfur analyzer. The effect of tellurium on 36MnVS4 non-quenched and tempered steel was studied. The results showed that some sulfides were transformed into Mn (Te,S) after tellurium addition. The area proportion and equivalent diameter of cluster sulfides decreased, and the area proportion and equivalent diameter of single sulfide increased. The maximum sulfur segregation index of unmodified billet was 1.22, and the maximum sulfur segregation index of modified billet was 1.14. Tellurium modification could effectively improve the segregation of sulfide in billet. After tellurium modification, the rating of sulfide in non-quenched and tempered steel bars decreased from fine series 2.5, coarse series 2.0 to fine series 2.0, coarse series 2.0. Tellurium modification could improve the rating of sulfide in non-quenched and tempered steel. Therefore, the tellurium modification was conducive to improving the morphology and distribution of sulfide, thus upgrading the sulfide rating.

Wavelength dispersive X-ray fluorescence spectrometry (WD-XRF) is increasingly utilized in environmental monitoring for determining inorganic elements in soil and sediment samples. The empirical coefficient method is one of the most commonly employed approach in calibration models. Incorporating appropriate matrix elements into the calibration model can significantly enhance the linear correlation between target elements and measured intensities, thereby improving the accuracy of results for unknown samples. However, an excessive number of matrix elements or unsuitable combinations in the calibration model may lead to "overfitting", where the model exhibits excellent fitting quality during calibration but yields analytical errors significantly higher than the fitting results when applied to real samples, failing to meet quality control (QC) requirements. This study proposed the use of stepwise regression analysis and single-element rotation optimization to efficiently screen matrix element combinations that satisfy QC criteria. After optimizing the matrix elements in the calibration model, the correlation coefficients of fitting indicators showed notable improvement. Experimental data from soil and sediment reference materials across 6 WD-XRF laboratories were used to validate the computational process. Results indicated that the screening outcomes of matrix elements depended on the reference materials included in the calibration model. Different combinations of reference materials might correspond to distinct screening results. For different target elements, 24-31 soil and sediment reference materials were employed as validation samples to evaluate the accuracy of the optimized calibration model. The qualification rates generally met QC requirements. Key considerations for practical application of the method were also discussed.

The steel materials including pipeline steel, iron-manganese alloy and gear steel were selected as the research objective. The effects of six major influencing factors (sample preparation, reference material selection, test condition, dead time, background subtraction, and correction method) on the quantitative results were investigated during the micro-area quantitative analysis by electron probe microanalyzer (EPMA). The results showed that the etching of specimen would cause an increase in the measured value of Mn content and a decrease in the measured value of Si content in the pipeline steel. The measurement errors of Fe-Si alloy or Fe-Mn alloy were both less than 0.1% whether selecting high-quality pure metal reference materials or alloy reference materials with similar composition. The accelerating voltage should be set for different elements, and the statistical error could be reduced by appropriately increasing the beam current and counting time. For the Fe element, the measurement error caused by dead time was higher than 1% when the count rate was above 50 000 cps. The background subtraction was recommended for the calibration curve method, and the background positions should be selected without the interference from other spectral peaks for the ZAF method. For example, the Ni element content in the stainless-steel specimen was 5% lower due to Fe K_β1 interference in BG (+) wavelength position. For the elements with a series of reference materials as C, Si and Mn, the calibration curve method could be preferentially used for determining the content of elements. In this study, the influence degree of each factor on the quantitative results was clarified through the actual detection of iron and steel specimens, and the optimization suggestions were provided, which could provide reference for the quantitative analysis by EPMA in the industry.

Trace impurities in zirconium dioxide will cause the change of electrical and optical properties of materials. Therefore, it is of great importance to accurately determine the trace impurity elements in zirconium dioxide. In experiments, the high purity indium was selected as the secondary cathode. Two sample preparation methods, i.e., flat and pin sample preparation, were investigated. The contents of Na, Mg, Si, P, S, Fe and Y in zirconium dioxide were determined by direct-current glow discharge mass spectrometry (dc-GDMS). The effects of different sample preparation areas and discharge parameters on signal intensity and signal stability time were studied. The experimental results showed that when the sample diameter by flat method was about 5 mm, the discharge parameter was 2 m A and 1 200 V, the signal intensity of matrix isotope ⁹⁰Zr remained stable at 1.4×10⁹ cps within short time. For pin sample preparation, when the sample length was about 5 mm and the area was the half of pin indium, and the discharge parameter was 2 m A and 1 000 V, the signal intensity of the matrix isotope ⁹⁰Zr was stable at 8.8×10⁸ cps in several minutes. The influence of two sample preparation methods on the determination results were also compared. For the pin sample preparation method, the results obtained with the standard relative sensitivity factor (RSF_Std) of equipment were basically consistent with those by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma emission spectrometry (ICP-AES). For the flat sample preparation method, the result consistency of Y was good, but the deviations were great for other elements. RSF_Std should be corrected using the quality control samples which were calibrated by ICP-MS and ICP-AES. After modification, the testing results of flat sample preparation were basically consistent with the reference values.

In order to detect gold in ore quickly, accurately and nondestructively, a physical model for the direct determination of gold by energy dispersive X-ray fluorescence spectrometry (EDXRF) was established by GEANT4 program and Monte Carlo method. The trajectory of particles going through three stages in the whole optical path, i.e., electron targeting, filter and sample excitation, was simulated. The counting effects and X-ray fluorescence spectra at different stages were analyzed. Monte Carlo method was used to simulate different parameters of various key components in EDXRF including optical tube target, tube voltage and filter. A simulation method for direct and rapid determination of gold in ores was established, which further broadened the detection means of gold and improved the detection efficiency. The simulation results using GEANT4 software showed that the high efficiency excitation of gold could be achieved under the following conditions: molybdenum target was selected as the anode target, the tube voltage was 40 kV, and the filter material was aluminum. The test platform was set up to test the different optical tube voltages and filters with different materials. The variation trend of testing results was basically consistent with the simulation results, indicating that the established simulation method could provide a design basis for the follow-up research gold determination by X-ray fluorescence spectrometry (XRF).

Total nitrogen is an important parameter for evaluating water quality and eutrophication in water system. Therefore, how to quickly and accurately determine the total nitrogen in water sample is important for evaluating environmental quality, reflecting the effect of water pollution treatment, and implementing environmental management. In this study, in order to improve the accuracy of total nitrogen determination in environmental water sample, 35 g/L alkaline potassium persulfate (K₂S₂O₈) solution was used as the digestion solution to convert nitrogen compounds in water sample into nitrate nitrogen. The solution of pure water, hydrochloric acid and titanium trichloride (V_H2O∶V_HCl∶V_TiCl3=1∶1∶4) was used as reducing solution to reduce nitrate nitrogen into nitric oxide gas which could be detected by the gas phase molecular absorption spectrometer. Then the solution of hydrochloric acid (1+2), glucose and sodium citrate were used as oxidation solution to remove the residual potassium persulfate and titanium oxides in the digestion device and pipelines. A method for the determination of total nitrogen in environmental water sample by online-ultraviolet digestion-gas phase molecular absorption spectrometry was established. The detection limit of total nitrogen determination in the method was 0.02 mg/L, the correlation coefficient of calibration curve was 0.999 9, and the online ultraviolet digestion efficiency (R) was 98.8%. The contents of total nitrogen in environmental standard sample for total nitrogen in water quality and standard usage solution were determined according to the experimental method. The relative standard deviations (RSD, n=6) of the measurement results were between 0 and 2.0%, and the relative errors (RE) were between -1.8% and 0.53%. The contents of total nitrogen in ten environmental water samples were parallelly determined by the experimental method and HJ 636-2012 Determination of total nitrogen-Alkaline potassium persulfate digestion UV spectrophotometric method, and the determination results of two methods were basically consistent. However, the complex high-temperature and high-pressure digestion pretreatments were not required in the proposed method, which was particularly suitable for the determination of low-concentration total nitrogen in environmental water samples.

Rare earth resources have become the strategic resources for modern industrialization construction. Bayan Obo rare earth concentrate is smelted and separated by high-temperature roasting with sulfuric acid, during which the presence of arsenic will reduce the product quality and cause environmental pollution. Therefore, it is necessary to establish a method for the determination of arsenic in Bayan Obo rare earth concentrate and water leaching residue in rare earth sulfuric acid roasting and smelting process. In experiments, the sample was dissolved by microwave digestion method in hydrochloric acid-nitric acid-hydrofluoric acid system. The mixture of hydrochloric acid, thiourea and ascorbic acid was added into the digestion solution. The content of arsenic was determined by hydride generation-atomic fluorescence spectrometry (HG-AFS). Consequently, a method for determination of arsenic in Bayan Obo rare earth concentrate and water leaching residue by microwave digestion-hydride generation-atomic fluorescence spectrometry was established. The carrier concentration and potassium borohydride mass concentration were optimized: the carrier concentration was 5% (hydrochloric acid), and the mass concentration of potassium borohydride was 20 g/L. The mass concentration of arsenic in range of 0.50-50.00 ng/mL showed good linear relationship with the corresponding fluorescence intensity, and the linear correlation coefficient of calibration curve was r=0.999 9. The limit of detection of arsenic in this method was 0.02 μg/g. The contents of arsenic in Bayan Obo rare earth concentrate and water leaching residue were determined according to the experimental method. The relative standard deviations (RSD, n= 6) of the results were 4.1% and 10%, respectively. The spiked recoveries were between 94% and 105%. The results were compared with those obtained by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), and it was found that the determination results of two methods had no significant difference.

The addition amount of silver and phosphorus into BCuPAg copper phosphorus solder should be accurately controlled. Two existing determination methods, i.e., gravimetric method and spectrophotometric method, can only be used for single element determination. In this study, the sample was pretreated in closed digestion system with hydrochloric acid-hydrogen peroxide. 22% hydrochloric acid was used as complexing agent to ensure that the samples were completely digested and Ag(I) existed stably as [Ag(Cl)₂]^- complex in the sample solution. Ag 328.068 nm and P 178.222 nm were selected as the analytical line for silver and phosphorus. The contents of silver and phosphorus were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method for determination of silver and phosphorus in BCuPAg copper phosphorus solder by ICP-AES was established. The calibration curves had good linear relationship in the linear range, and the correlation coefficients were not less than 0.999 9. The contents of silver and phosphorus in two copper alloy standard materials and one BCuPAg copper phosphorus solder sample were determined according to the experimental method, and the relative standard deviations (RSD, n=6) of the results were between 0.56% and 1.7%. The contents of silver and phosphorus in two copper alloy standard materials and five BCuPAg copper phosphorus solder samples were determined according to the experimental method. The found results had no significant difference with the certified values or those obtained by machinery industry standard JB/T 7520.

With the increasing demand for boron resources in China, the accurate analysis of boron content in potassium ore brine is particularly important for the development and utilization of boron resources. In experiments, the brine sample was diluted for 5 times. Then 8.0 g of cation exchange resin was added for ion exchange for 30 min. High concentration metal cations in the brine could be separated. B 249.678 nm was selected as the analytical spectral line. A method for the determination of boron in potassium ore brine by ion exchange resin separation-inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. The calibration curve of boron had a good linear relationship with the correlation coefficient of 1.000. The limit of detection of boron in the method was 0.002 6 μg/mL, and the limit of quantification was 0.010 4 μg/mL. The proposed method was applied to the determination of boron in seven potassium ore brine samples. The relative standard deviations (RSD, n=12) of determination results were between 0.63% and 1.1%, and the spiked recoveries were between 95% and 105%, which could meet the requirements in DZT 0130.6-2006 Geological and Mineral Laboratory Testing Quality Management Specifications-Part 6: Water Sample Analysis. Seven potassium ore brine samples were pretreated according to the experimental method, and the contents of boron were determined by this method and curcumin spectrophotometry(HJ/T 49-1999), respectively. The determination results of two methods were consistent. The proposed method could effectively solve the problems of high salt concentration in salt-lake brine, serious matrix interference, and difficulty in accurate determination of conventional sample pretreatment. It could provide reliable data support and technical guarantee for the development and utilization of salt-lake brine.

Coal-based activated carbon is widely used due to its well-developed pore structure, excellent adsorption performance, and high mechanical strength. The accurate determination of impurity elements in activated carbon is of great significance for its application and research. In experiments, 5 g of the sample could be completely ashed after ashing at 800 ℃ for 2 h. The elements to be tested were fully extracted with 8 mL of aqua regia, and a small amount of ash residue did not influence the subsequent measurements. Cu 324.754 nm, Fe 259.940 nm, Zn 213.856 nm, Ni 231.604 nm, Pb 229.651 nm and Cr 267.716 nm were selected as the analytical lines of copper, iron, zinc, nickel, lead and chromium, respectively. The contents of copper, iron, zinc, nickel, lead and chromium were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method for the determination of trace copper, iron, zinc, nickel, lead and chromium in coal-based activated carbon by ICP-AES with dry ashing and aqua regia extraction was established. The linear correlation coefficients of calibration curves for the measured elements were 0.999. The limit of quantification of copper, iron, zinc, and chromium were 0.000 02%, the limit of quantification of nickel was 0.000 05%, and the limit of quantification of lead was 0.000 2%, respectively. The contents of copper, iron, zinc, nickel, lead and chromium in four coal-based activated carbon samples were determined according to the experimental method. The relative standard deviations (RSD, n=7) of the results were between 1.0% and 7.9%, and the spiked recoveries of elements were between 92% and 112%.

Solid oxide fuel cell (SOFC) is a current research focus in the energy field. The cathode materials are key components for SOFC. In this study, a method for the determination of eight major and minor components in SOFC cathode materials (including La₂O₃, BaO, SrO, Fe₂O₃, Co₂O₃, Mn₃O₄, NiO and CeO₂) by X-ray fluorescence spectrometry (XRF) with fusion sample preparation was established. The experimental parameters including flux type, fusion temperature and duration, and oxidizing agents were systematically investigated. The results showed that the transparent, homogeneous, and intact glass beads could be prepared under the following experimental conditions: the mixed flux (m(Li₂B₄O₇)∶m(LiBO₂)=67∶33) was used; the dilution ratio was 1∶10; 1 mL of lithium nitrate solution was used as the oxidizer; 3 drops of lithium bromide solution were used as the releasing agent; the sample was fused at 1 200 ℃ for 12 min. The calibration curves were established using the synthetic calibration samples. Moreover, the spectral overlapping and absorption-enhancement effect were discussed. The linear correlation coefficients of calibration curves for the measured components were not less than 0.999. The limits of detection in this method were between 0.013% and 0.082%. The proposed method was applied to the determination of eight major and minor components in SOFC cathode materials, and the relative standard deviations (RSD, n=6) of determination results were between 0.49% and 5.1%. The contents of eight major and minor components in SOFC cathode materials were determined by this method and conventional chemical wet method. The determination results were investigated by t test method. The results showed that there was no significant difference.