Analysis program, analyzer, and analysis method

Abstract

To provide an analysis program, an analyzer, and an analysis method that can reduce the workload on an analysis person.SOLUTION: An analysis program causes a computer to execute automatic analysis processing of automatically repeating one sample analysis processing having data reading processing S20 of reading X-ray diffraction data obtained by conducting X-ray diffraction measurement of a sample, half-width specification processing S30 of specifying the half width of a diffraction peak by analyzing the X-ray diffraction data, and crystallite diameter calculation processing S50 of determining the crystallite diameter of the sample from the half width of the diffraction peak, and determining the crystallite diameters of a plurality of samples. The crystallite diameters of the plurality of samples are automatically determined, and the workload on an analysis person can thus be reduced.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an analysis program, an analysis device, and an analysis method, and more particularly to a program, device, and method for determining crystallite diameter from X-ray diffraction data. [Background technology]

[0002] X-ray diffraction is known as a method for obtaining information about the crystallinity of a substance (hereinafter referred to as "crystal information"). Crystallite size, which is one piece of crystal information about a substance, can be determined from the results of X-ray diffraction measurements (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-138302 Summary of the Invention [Problem to be solved by the invention]

[0004] When developing new materials, it is necessary to prepare a large number of samples by gradually changing the raw material composition or processing conditions, and to determine the crystallite size of each sample. In such cases, the number of crystallite size analyses to be processed increases, placing a heavy workload on analysts.

[0005] In view of the above circumstances, an object of the present invention is to provide an analysis program, an analysis device, and an analysis method that can reduce the workload of an analyst. [Means for solving the problem]

[0006] The analysis program of the first embodiment is a program for causing a computer to function as an analysis device, and is characterized in that it automatically repeats a single sample analysis process including a data reading process for reading X-ray diffraction data obtained by X-ray diffraction measurement of a sample, a half-width determination process for analyzing the X-ray diffraction data to determine the half-width of the diffraction peak, and a crystallite diameter calculation process for determining the crystallite diameter of the sample from the half-width of the diffraction peak, and causes the computer to execute an automatic analysis process for determining the crystallite diameter of each of a plurality of the samples. The analysis program of the second aspect is characterized in that, in the first aspect, the single sample analysis process includes a diffraction peak selection process, in which the diffraction angles and half-widths of multiple diffraction peaks are identified in the half-width identification process, the diffraction peak selection process selects a diffraction peak having a diffraction angle closest to a predetermined reference diffraction angle for a specific type of substance, and the crystallite size calculation process calculates the crystallite size of the sample from the half-width of the diffraction peak selected in the diffraction peak selection process. The analysis program of a third aspect is the second aspect, characterized in that, in the half-value width specifying process, a warning is output when a nearby peak exists in the diffraction pattern. The analysis program of the fourth aspect is characterized in that in the second aspect, a warning is output when the diffraction angle of the selected diffraction peak deviates from the reference diffraction angle in the diffraction peak selection process. The analysis program of the fifth aspect is characterized in that, in any of the first to fourth aspects, the automatic analysis process includes a calibration process for determining the relationship between the diffraction angle and the instrument-specific broadening width from the diffraction angle and half-width of multiple diffraction peaks obtained by analyzing X-ray diffraction data of a standard sample, and the crystallite size calculation process determines the crystallite size of the sample from a corrected value obtained by subtracting the instrument-specific broadening width determined from the diffraction angle of the diffraction peak based on the relationship between the diffraction angle and the instrument-specific broadening width from the half-width of the diffraction peak. The analysis program of a sixth aspect is characterized in that, in any one of the first to fifth aspects, the single-sample analysis process includes a file output process of outputting the determined crystallite diameter to a file. The analysis device of the seventh aspect is characterized by comprising a computer in which the analysis program of any one of the first to sixth aspects is installed. The analysis method of the eighth aspect is characterized by comprising an automatic analysis processing step of determining the crystallite diameter of each of a plurality of samples using the analysis device of the seventh aspect, an evaluation step of evaluating whether the results obtained by the automatic analysis processing step are appropriate, and a reanalysis step of determining the crystallite diameter again for samples that are evaluated as inappropriate in the evaluation step. [Effects of the Invention]

[0007] According to the first aspect, the crystallite diameter of each of a plurality of samples is automatically determined, thereby reducing the workload of the analyst. According to the second embodiment, it is possible to select a diffraction peak suitable for determining the crystallite diameter of a target substance from among a plurality of diffraction peaks. According to the third aspect, by informing the analyst of the presence of a nearby peak, it is possible to prompt the analyst to check whether the half width of the diffraction peak is properly specified. According to the fourth aspect, by informing the analyst that the diffraction angle of the selected diffraction peak deviates from the reference diffraction angle, it is possible to prompt the analyst to check whether the selected diffraction peak is appropriate. According to the fifth embodiment, the crystallite diameter can be determined with high accuracy by subtracting the device-specific width from the half-width of the diffraction peak to determine the width due to the crystallites, and then determining the crystallite diameter from the width due to the crystallites. According to the sixth aspect, the analysis results are automatically output to a file, which further reduces the workload of the analyst. According to the seventh aspect, the crystallite diameter of each of a plurality of samples is automatically determined, thereby reducing the workload of the analyst. According to the eighth aspect, reanalysis is required only when the analysis results automatically obtained by the analysis device are inappropriate, which reduces the frequency of manual analysis by the analyst and reduces the workload. Moreover, the analyst can obtain appropriate results that have already been evaluated. [Brief explanation of the drawings]

[0008] [Figure 1] It is a functional block diagram of an analysis device according to an embodiment. [Figure 2] It is a flowchart showing an automatic analysis process performed by an analysis device according to an embodiment. [Figure 3] It is a flowchart showing an analysis method according to an embodiment.

Embodiments for Carrying Out the Invention

[0009] Next, embodiments of the present invention will be described based on the drawings. (Analysis Program, Analysis Device) An analysis device AA according to an embodiment of the present invention is a device for analyzing X-ray diffraction data to obtain the crystallite size of a sample. The X-ray diffraction data is obtained by performing X-ray diffraction measurement on a powdery sample.

[0010] The sample is not particularly limited. For example, it is a positive electrode active material of a lithium ion secondary battery. Examples of the positive electrode active material include lithium metal composite oxides such as lithium nickel manganese cobalt composite oxide (NMC) and lithium nickel cobalt aluminum composite oxide (NCA). The lithium metal composite oxide has the general formula: Li s Ni 1-x M x O α (where s, x, and α are, for example, 0.95 ≦ s ≦ 1.30, 0 < x ≦ 0.65, 1.9 ≦ α ≦ 4.2, and M is at least one metal element selected from the group consisting of Co, Mn, W, Mo, V, Ca, Mg, Sr, Ba, Ti, Cr, Zr, Al, Nb, Ta, Si, P, B, S).

[0011] At the site of developing a new lithium metal composite oxide, a large number of samples are produced while gradually changing the composition of the raw materials or the processing conditions, and the crystallite size of each sample is determined. In such a case, it is necessary to analyze a large number of X-ray diffraction data to obtain the crystallite size. The analysis device AA is preferably used in such a case.

[0012] As shown in Figure 1, the analysis device AA has various functions. The analysis device AA is made up of a computer consisting of a CPU, memory, etc. The functions of the analysis device AA are realized by installing an analysis program on the computer. The analysis program may be made up of multiple subprograms. The analysis program may also be made up of a combination of commercially available X-ray diffraction analysis software, spreadsheet software, and robotic process automation (RPA) software. Analysis can be automated by automatically operating the X-ray diffraction analysis software and spreadsheet software using the RPA software. The analysis program may be stored on a computer-readable storage medium.

[0013] The analytical device AA has a memory unit 11, a calibration unit 12, a data reading unit 13, a half-width determining unit 14, a diffraction peak selecting unit 15, a crystallite diameter calculating unit 16, and a file output unit 17. These may be configured as hardware or may be realized by installing a program on a computer. The analytical device AA may also have input devices such as a keyboard and a mouse. The analytical device AA may also have output devices such as a display and a printer.

[0014] The memory unit 11 is a partial area of ​​a storage device such as a hard disk, for example, a specific folder. One or more X-ray diffraction data are stored in the memory unit 11. The X-ray diffraction data is generated by an X-ray diffraction device and stored in the memory unit 11 by operation of the analyst. The X-ray diffraction data is a file for each sample. When X-ray diffraction measurements are performed on multiple samples, the same number of X-ray diffraction data files as the number of samples are generated and stored in the memory unit 11. The X-ray diffraction data includes diffraction intensity values ​​for each diffraction angle 2θ. When multiple X-ray diffraction data are stored in the memory unit 11, they are X-ray diffraction data for multiple samples of the same type of material. However, multiple X-ray diffraction data for different types of materials may also be stored in the memory unit 11 in a manner that allows the types of materials to be distinguished.

[0015] The calibration unit 12 determines the relationship between the diffraction angle and the instrument-specific broadening width from the diffraction angle and half-width of multiple diffraction peaks obtained by analyzing the X-ray diffraction data of the standard sample. The determined relationship between the diffraction angle and the instrument-specific broadening width is stored in the memory unit 11 as calibration data.

[0016] The data reading unit 13 reads the X-ray diffraction data stored in the memory unit 11. By reading the X-ray diffraction data, a diffraction pattern is obtained with the horizontal axis representing the diffraction angle 2θ and the vertical axis representing the diffraction intensity. The half-width identifying unit 14 analyzes the X-ray diffraction data to identify the diffraction angle (peak position) and half-width of each of the multiple diffraction peaks contained in the diffraction pattern. The diffraction peak selecting unit 15 selects a diffraction peak suitable for calculating the crystallite diameter from the multiple diffraction peaks contained in the diffraction pattern. The crystallite diameter calculating unit 16 calculates the crystallite diameter of the sample from the half-width of the selected diffraction peak.

[0017] The file output unit 17 outputs the results obtained by the analysis as a file. The analysis result file is stored in the memory unit 11. The analysis result file may be a file for each sample, or may be a single file that compiles the analysis results of multiple samples. The analysis result file contains at least information that uniquely identifies the sample, such as the sample name, and information on the crystallite size obtained by the analysis. The analysis result file may also contain crystal information other than the crystallite size.

[0018] The data reading unit 13 and the half-width specifying unit 14 may be realized by X-ray diffraction analysis software. Also, the calibration unit 12, the diffraction peak selecting unit 15, the crystallite diameter calculating unit 16, and the file output unit 17 may be realized by spreadsheet software. Also, the analysis result file may be a file that can be saved, displayed, and edited by spreadsheet software.

[0019] Next, the automatic analysis process performed by the analysis device AA will be described with reference to the flowchart shown in FIG. 2, the analytical device AA performs a calibration process S10, a data reading process S20, a half-width determination process S30, a diffraction peak selection process S40, a crystallite diameter calculation process S50, and a file output process S60. However, of these steps, the analytical device AA only needs to perform the data reading process S20, the half-width determination process S30, and the crystallite diameter calculation process S50. The analytical device AA only needs to perform the calibration process S10, the diffraction peak selection process S40, and the file output process S60 as needed.

[0020] The automatic analysis process includes a single-sample analysis process for determining the crystallite diameter of one sample. The single-sample analysis process is a series of processes including at least a data reading process S20, a half-width determination process S30, and a crystallite diameter calculation process S50. The single-sample analysis process may also include a diffraction peak selection process S40 and a file output process S60. In the example shown in FIG. 2, the series of processes from the data reading process S20 to the file output process S60 corresponds to the single-sample analysis process.

[0021] The analysis device AA repeats the single-sample analysis process as many times as the number of samples (X-ray diffraction data) to determine the crystallite diameter of each of the multiple samples. The automatic analysis process includes at least a process of repeating the single-sample analysis process. The automatic analysis process may also include a calibration process S10. In the example shown in FIG. 2, the combined process of repeating the single-sample analysis process and the calibration process S10 corresponds to the automatic analysis process.

[0022] To calibrate the X-ray diffractometer, a standard sample is subjected to X-ray diffraction measurement in advance to obtain X-ray diffraction data. Examples of standard samples that can be used include Si powder and LaB6 powder. X-ray analysis measurements of the standard sample are performed at a predetermined frequency, for example, once a day. The diffraction pattern of the standard sample contains multiple diffraction peaks. The diffraction angle and half-width of each of these multiple diffraction peaks are specified.

[0023] The calibration unit 12 determines the relationship between the diffraction angle 2Θ and the device-specific broadening width b0 from the diffraction angles and half-widths of multiple diffraction peaks obtained by analyzing the X-ray diffraction data of the standard sample (calibration process S10). For example, as shown in the following equation (1), the device-specific broadening width b0 is specified as a function f with the diffraction angle 2Θ as a variable.

number

[0024] The function f can be a quadratic function, a cubic function, a quartic function, an exponential function, or the like. The function f can be determined by fitting the diffraction angles and half-widths of multiple diffraction peaks with a desired function. The relationship between the diffraction angle 2Θ and the device-specific beam width b0 is stored in the memory unit 11 as calibration data.

[0025] Next, the data reading unit 13 reads the X-ray diffraction data of the sample stored in the storage unit 11 (data reading process S20). Here, if multiple pieces of X-ray diffraction data are stored in the storage unit 11, one of them is read.

[0026] Next, the half-width specifying unit 14 analyzes the read X-ray diffraction data to specify the diffraction angle 2θ and half-width b of the diffraction peak (half-width specifying process S30). Typically, a diffraction pattern contains multiple diffraction peaks. The half-width specifying unit 14 specifies the diffraction angle 2θ and half-width b of each of these multiple diffraction peaks. Here, the half-width means the full width of the peak profile at an intensity value that is half the peak intensity.

[0027] For example, the half-value width specifying unit 14 fits the diffraction pattern with a profile function to specify profile information such as the diffraction angle 2θ of the diffraction peak, the half-value width b, etc. The fitting method is not particularly limited, but full pattern fitting, the Rietveld method, etc. can be used.

[0028] The half-width specifying unit 14 may output a warning when adjacent peaks are present in the diffraction pattern. It can be determined that adjacent peaks are present when the ratio of the diffraction angles 2θ between two adjacent diffraction peaks among the multiple diffraction peaks included in the diffraction pattern is equal to or less than a threshold. It can also be determined that adjacent peaks are present when the difference in the diffraction angles 2θ between two adjacent diffraction peaks is equal to or less than a threshold.

[0029] Adjacent peaks may be peaks resulting from Kα2 radiation emitted from the copper anode of the X-ray diffraction instrument or peaks resulting from impurities contained in the sample. The presence of adjacent peaks can reduce the fitting accuracy of the diffraction pattern or cause the half-width b of the diffraction peak to be determined to be wider than it actually is. Informing the analyst of the presence of adjacent peaks can alert them to the appropriateness of the half-width b of the diffraction peak.

[0030] Next, the diffraction peak selection unit 15 selects a diffraction peak at a reference diffraction angle 2θ from among a plurality of diffraction peaks included in the diffraction pattern. S A diffraction peak having a diffraction angle 2θ closest to the reference diffraction angle 2θ is selected (diffraction peak selection process S40). S is predetermined for a particular type of material.

[0031] The term "specific type of substance" refers to the type of substance for which the crystallite size is to be determined. For example, substances contained in "lithium metal composite oxides," more specifically, substances contained in "lithium nickel manganese cobalt composite oxides," and substances contained in "lithium nickel cobalt aluminum composite oxides," each fall under the category of "specific type of substance." Furthermore, in addition to "lithium metal composite oxides," crystals containing multiple metal elements, such as substances contained in cesium tungsten composite oxide (CWO (registered trademark)) and substances contained in gadolinium gallium garnet single crystals (SGGG), also fall under the category of "specific type of substance."

[0032] The diffraction angle 2θ of the diffraction peak identified by the half-value width identifying unit 14 is the reference diffraction angle 2θ STherefore, the reference diffraction angle 2θ S By selecting the diffraction peak having the diffraction angle 2θ closest to the target value, a diffraction peak suitable for determining the crystallite size of the target substance is selected from among the multiple diffraction peaks.

[0033] The reference diffraction angle is 2θ S may be one or more. S is determined, the half-value width specifying unit 14 determines the plurality of reference diffraction angles 2θ S Select multiple diffraction peaks corresponding to

[0034] The diffraction peak selection unit 15 selects the diffraction angle 2θ of the selected diffraction peak as the reference diffraction angle 2θ S If the diffraction angle 2θ of the selected diffraction peak deviates from the reference diffraction angle 2θ, a warning may be output. S If the ratio is equal to or greater than a threshold, it can be determined that there is a deviation. S If the difference is equal to or greater than a threshold, it may be determined that there is a deviation.

[0035] The diffraction angle 2θ of the selected diffraction peak is the reference diffraction angle 2θ S If the diffraction angle 2θ of the selected diffraction peak is different from the reference diffraction angle 2θ, it is possible that a peak other than the target diffraction peak, such as a peak derived from an impurity contained in the sample, has been selected. S By informing the analyst that the diffraction peaks deviate from the normalized value, the analyst can be alerted to the appropriateness of the selected diffraction peaks.

[0036] Next, the crystallite diameter calculation unit 16 determines the crystallite diameter D of the sample from the half-width b of the diffraction peak selected by the diffraction peak selection unit 15. If the diffraction peak selection unit 15 selects multiple diffraction peaks, the crystallite diameter calculation unit 16 determines the crystallite diameter D from each of the half-width b of the selected multiple diffraction peaks. In this case, the number of crystallite diameters D to be determined is also multiple.

[0037] The crystallite size is calculated using the Scherrer equation shown in the following formula (2).

number

[0038] The full width at half maximum (b) of the diffraction peak may be used as the diffraction peak broadening width (β) directly. However, it is preferable to use a corrected value obtained by subtracting the instrument-specific broadening width (b0) from the full width at half maximum (b) of the diffraction peak as the diffraction peak broadening width (β). Here, the instrument-specific broadening width (b0) is determined from the diffraction angle (2θ) of the diffraction peak based on the relationship between the diffraction angle (2θ) and the instrument-specific broadening width (b0) determined by the calibration unit 12. That is, the instrument-specific broadening width (b0) at the diffraction angle (2θ) of the measured diffraction peak is determined by substituting the diffraction angle (2θ) of the diffraction peak for the diffraction angle (2θ), which is a variable of the function (f) shown in Equation (1).

[0039] The diffraction peak broadening width β can be calculated using the following formula (3) or (4): Based on formula (3) or (4), the crystallite broadening width β can be calculated by subtracting the device-specific broadening width b0 from the diffraction peak half-width b. The crystallite diameter D can be calculated with high accuracy by calculating the crystallite diameter D from the crystallite broadening width β.

number

number

[0040] Next, the file output unit 17 outputs the crystallite diameter D calculated by the above process to a file (file output process S60). That is, the file output unit 17 stores an analysis result file recording the analysis results in the storage unit 11. In addition to the crystallite diameter D, the analysis result file may contain information such as the diffraction angle 2θ and half-width b of the diffraction peak used to calculate the crystallite diameter D. If applicable, a warning is displayed indicating that a nearby peak exists, and the diffraction angle 2θ of the selected diffraction peak is the reference diffraction angle 2θ. S The document may also include a warning that the document is deviating from the

[0041] When multiple X-ray diffraction data are stored in the memory unit 11, the analyzer AA automatically repeats the single sample analysis process from the data read process S20 to the file output process S60 while changing the X-ray diffraction data to be processed. That is, multiple X-ray diffraction data are read one by one and processed until all X-ray diffraction data are analyzed. When there is no unanalyzed X-ray diffraction data, the process ends. In this way, the crystallite diameter D of each of the multiple samples is determined.

[0042] As described above, by using the analytical device AA, the crystallite diameter D of each of multiple samples can be automatically determined, eliminating the need for the analyst to perform any operations, thereby reducing the analyst's workload. Furthermore, the analysis results are automatically output to a file, further reducing the analyst's workload.

[0043] (Analysis method) Next, an analysis method according to one embodiment of the present invention will be described. 3, first, the analyst performs X-ray diffraction measurement on a sample to obtain X-ray diffraction data (X-ray diffraction measurement step S100). If there are multiple samples, the analyst performs X-ray diffraction measurement on the multiple samples to obtain X-ray diffraction data for each sample. The obtained X-ray diffraction data is then stored in memory unit 11 of analysis device AA.

[0044] Next, the X-ray diffraction data is analyzed using the analytical device AA (automatic analysis processing step S200). The automatic analysis processing performed by the analytical device AA is as shown in the flowchart of Figure 2. That is, the analytical device AA automatically analyzes all the X-ray diffraction data obtained by measuring multiple samples and determines the crystallite diameter. The analytical device AA also outputs the analysis results as a file.

[0045] Next, the analyst evaluates whether the results obtained by the automatic analysis processing step S200 are appropriate (evaluation step S300). Here, the analyst evaluates the analysis results by viewing the analysis result file stored in the memory unit 11 of the analysis device AA. For example, if there is a warning that a nearby peak exists, the analyst checks whether the fitting of the diffraction pattern is appropriate. In addition, the analyst checks whether the diffraction angle 2θ of the selected diffraction peak is within the reference diffraction angle 2θ. S If there is a warning that the diffraction peak is deviating from the normalized value, check whether the selected diffraction peak is appropriate.

[0046] If any analytical results are evaluated as inappropriate in the evaluation step S300, only the X-ray diffraction data of that sample is analyzed, and the crystallite size is determined again (reanalysis step S400). Reanalysis is performed by the analyst by changing the fitting conditions of the diffraction pattern or changing the selected diffraction pattern. For reanalyzed samples, the results obtained by reanalysis are adopted instead of the results obtained by the automatic analysis process. On the other hand, if no analytical results are evaluated as inappropriate, the process ends without reanalysis.

[0047] As described above, reanalysis is required only when the analysis results automatically obtained by the analysis device AA are inappropriate, which reduces the frequency of manual analysis by the analyst and reduces the workload. Moreover, the analyst can obtain appropriate results that have already been evaluated. [Explanation of symbols]

[0048] AA analysis device 11 Storage section 12 Proofreading Department 13 Data reading section 14 Half-value width specification part 15 Diffraction peak selection section 16 Crystallite size calculation section 17 File output section

Claims

1. A program for causing a computer to function as an analysis device, a data reading process for reading X-ray diffraction data obtained by X-ray diffraction measurement of a sample; a half-value width determination process for determining a half-value width of a diffraction peak by analyzing the X-ray diffraction data; a crystallite size calculation process for calculating the crystallite size of the sample from the half width of the diffraction peak; and causing a computer to automatically execute an automatic analysis process for determining the crystallite diameter of each of the plurality of samples by automatically and repeatedly performing a single sample analysis process having the steps of: An analysis program characterized by:

2. the one sample analysis process includes a diffraction peak selection process; In the half-value width specifying process, the diffraction angles and half-value widths of a plurality of diffraction peaks are specified; In the diffraction peak selection process, a diffraction peak having a diffraction angle closest to a predetermined reference diffraction angle for a specific type of material is selected; In the crystallite size calculation process, the crystallite size of the sample is calculated from the half width of the diffraction peak selected in the diffraction peak selection process.

2. The analysis program according to claim 1.

3. In the half-value width specifying process, if there is a nearby peak in the diffraction pattern, a warning is output.

3. The analysis program according to claim 2.

4. In the diffraction peak selection process, if the diffraction angle of the selected diffraction peak deviates from the reference diffraction angle, a warning is output.

3. The analysis program according to claim 2.

5. the automatic analysis process includes a calibration process for determining a relationship between a diffraction angle and a device-specific broadening width from the diffraction angles and half-widths of a plurality of diffraction peaks obtained by analyzing X-ray diffraction data of a standard sample; In the crystallite diameter calculation process, the crystallite diameter of the sample is calculated from a corrected value obtained by subtracting the device-specific broadening width, which is determined from the diffraction angle of the diffraction peak based on the relationship between the diffraction angle and the device-specific broadening width, from the half-value width of the diffraction peak.

2. The analysis program according to claim 1.

6. The one-sample analysis process includes a file output process of outputting the determined crystallite diameter to a file.

2. The analysis program according to claim 1.

7. A computer having the analysis program according to any one of claims 1 to 6 installed thereon. An analytical device characterized by:

8. an automatic analysis processing step of determining the crystallite diameter of each of the plurality of samples using the analysis device according to claim 7; an evaluation step of evaluating whether the results obtained by the automatic analysis processing step are appropriate; a reanalysis step of determining the crystallite size again for the sample evaluated as inappropriate in the evaluation step. An analysis method characterized by:

Images